BQ51013B-Q1
SLUSEE3 – JULY 2021
BQ51013B-Q1: Automotive Highly Integrated Wireless Receiver Qi (WPC v1.2)
Compliant Power Supply
1 Features
2 Applications
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Qualified for automotive applications
AEC-Q100 qualified with the following results:
– Device temperature grade 1: –40°C to +125°C
ambient operating temperature
– Device HBM ESD classification level 2
– Device CDM ESD classification level C4B
Integrated wireless power supply receiver solution
– 93% overall peak AC-DC efficiency
– Full synchronous rectifier
– WPC v1.2 compliant communication control
– Output voltage conditioning
– Only IC required between Rx coil and output
Wireless power consortium (WPC) v1.2 compliant
(FOD enabled) highly accurate current sense
Dynamic rectifier control for improved load
transient response
Dynamic efficiency scaling for optimized
performance over wide range of output power
Adaptive communication limit for robust
communication
Supports 20-V maximum input
Low-power dissipative rectifier overvoltage clamp
(VOVP = 15 V)
Thermal shutdown
Multifunction NTC and control pin for temperature
monitoring, charge complete, and fault host control
WPC v1.2 compliant receivers
Cell phones and smart phones
Headsets
Digital cameras
Portable media players
Handheld devices
3 Description
The BQ51013B-Q1 device is a single-chip, advanced,
flexible, secondary-side device for wireless power
transfer in portable applications capable of providing
up to 5 W. The BQ51013B-Q1 devices provide
the receiver (RX) AC-to-DC power conversion and
regulation while integrating the digital control required
to comply with the Wireless Power Consortium
(WPC) Qi v1.2 communication protocol. Together with
the BQ50012A primary-side controller (or other Qi
transmitter), the BQ51013B-Q1 enables a complete
contactless power transfer system for a wireless
power supply solution. Global feedback is established
from the secondary to the primary to control the power
transfer process using the Qi v1.2 protocol.
The BQ51013B-Q1 integrates a low-resistance
synchronous rectifier, low-dropout regulator (LDO),
digital control, and accurate voltage and current loops
to ensure high efficiency and low power dissipation.
Device Information(1)
PART NUMBER
BQ51013B-Q1
(1)
AD
COMM1
C4
BOOT1
ROS
CBOOT1
RECT
C1
AC1
Power
C3
AC to DC
D1
BQ51013B-Q1
Drivers
Rectification
Voltage/
Current
Conditioning
System
Load
R4
BQ51013B-Q1
C2
4.50 mm × 3.50 mm
OUT
CCOMM1
COIL
VQFN (20)
BODY SIZE (NOM)
For all available packages, see the orderable addendum at
the end of the data sheet.
System
Load
AD-EN
PACKAGE
Communication
HOST
TS/CTRL
AC2
NTC
BOOT2
Controller
CBOOT2
COMM2
CHG
CLAMP2
EN1
Bi-State
CLAMP1
EN2
Bi-State
CCOMM2
CCLAMP2
CCLAMP1
ILIM
R1
FOD
PGND
RFOD
V/I
Sense
Controller
Battery
Charger
LI-Ion
Battery
Tri-State
BQ500212A
Transmitter
Receiver
Wireless Power System Overview
Simplified Schematic
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
Table of Contents
1 Features............................................................................1
2 Applications..................................................................... 1
3 Description.......................................................................1
4 Revision History.............................................................. 2
5 Description (continued).................................................. 3
6 Device Comparison Table...............................................4
7 Pin Configuration and Functions...................................5
8 Specifications.................................................................. 6
8.1 Absolute Maximum Ratings........................................ 6
8.2 ESD Ratings............................................................... 6
8.3 Recommended Operating Conditions.........................6
8.4 Thermal Information....................................................7
8.5 Electrical Characteristics.............................................7
8.6 Typical Characteristics.............................................. 10
9 Detailed Description......................................................14
9.1 Overview................................................................... 14
9.2 Functional Block Diagram......................................... 15
9.3 Feature Description...................................................15
9.4 Device Functional Modes..........................................29
10 Application and Implementation................................ 30
10.1 Application Information........................................... 30
10.2 Typical Applications................................................ 30
11 Power Supply Recommendations..............................38
12 Layout...........................................................................38
12.1 Layout Guidelines................................................... 38
12.2 Layout Example...................................................... 39
13 Device and Documentation Support..........................40
13.1 Device Support....................................................... 40
13.2 Receiving Notification of Documentation Updates..40
13.3 Support Resources................................................. 40
13.4 Trademarks............................................................. 40
13.5 Electrostatic Discharge Caution..............................40
13.6 Glossary..................................................................40
14 Mechanical, Packaging, and Orderable
Information.................................................................... 40
4 Revision History
2
DATE
REVISION
NOTES
July 2021
*
Initial Release
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
5 Description (continued)
The BQ51013B-Q1 also includes a digital controller that calculates the amount of power received by the mobile
device within the limits set by the WPC v1.2 standard. The controller then communicates this information to the
transmitter (TX) to allow the TX to determine if a foreign object is present within the magnetic interface and
introduces a higher level of safety within magnetic field. This Foreign Object Detection (FOD) method is part of
the requirements under the WPC v1.2 specification.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
3
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
6 Device Comparison Table
DEVICE
4
FUNCTION
VOUT (VBAT-REG)
MAXIMUM POUT
I2C
BQ51003
Wireless Receiver
5V
2.5 W
No
BQ51013B
Wireless Receiver
5V
5W
No
BQ51013B-Q1
Automotive Wireless Receiver
5V
5W
No
BQ51020
Wireless Receiver
4.5 to 8 V
5W
No
BQ51021
Wireless Receiver
4.5 to 8 V
5W
Yes
BQ51050B
Wireless Receiver and Direct Charger
4.2 V
5W
No
BQ51051B
Wireless Receiver and Direct Charger
4.35 V
5W
No
BQ51052B
Wireless Receiver and Direct Charger
4.4 V
5W
No
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
PGND
PGND
1
20
7 Pin Configuration and Functions
AC1
2
19
AC2
BOOT1
3
18
RECT
OUT
4
17
BOOT2
CLAMP1
5
16
CLAMP2
Thermal
Pad
15
COMM2
CHG
7
14
FOD
AD-EN
8
13
TS/CTRL
AD
9
12
ILIM
EN2
EN1
11
6
10
COMM1
Not to scale
The exposed thermal pad should be connected to ground.
Figure 7-1. RHL Package 20-Pin VQFN Top View
Table 7-1. Pin Functions
PIN
NAME
NO.
I/O
DESCRIPTION
AC1
2
I
AC2
19
I
AD
9
I
If AD functionality is used, connect this pin to the wired adapter input. When VAD-Pres is applied to this pin
wireless charging is disabled and AD_EN is driven low. Connect a 1-µF capacitor from AD to PGND. If
unused, the capacitor is not required and AD should be connected directly to PGND.
AD-EN
8
O
Push-pull driver for external PFET when wired charging is active. Float if not used.
BOOT1
3
O
BOOT2
17
O
Bootstrap capacitors for driving the high-side FETs of the synchronous rectifier. Connect a 10-nF ceramic
capacitor from BOOT1 to AC1 and from BOOT2 to AC2.
CHG
7
O
Open-drain output – active when OUT is enabled. Float or tie to PGND if unused.
CLAMP2
16
O
CLAMP1
5
O
Open-drain FETs which are used for a non-power dissipative overvoltage AC clamp protection. When the
RECT voltage goes above 15 V, both switches will be turned on and the capacitors will act as a low
impedance to protect the device from damage. If used, capacitors are used to connect CLAMP1 to AC1 and
CLAMP2 to AC2. Recommended connections are 0.47-µF capacitors.
COMM1
6
O
COMM2
15
O
EN1
10
I
EN2
11
I
FOD
14
I
AC input from receiver coil.
Open-drain outputs used to communicate with primary by varying reflected impedance. Connect a capacitor
from COMM1 to AC1 and a capacitor from COMM2 to AC2 for capacitive load modulation. For resistive
modulation connect COMM1 and COMM2 to RECT through a single resistor. See Section 9.3.10 for more
information.
Inputs that allow user to enable and disable wireless and wired charging :
Wireless charging is enabled unless AD voltage > VAD_Pres.
Dynamic communication current limit disabled.
AD-EN pulled low, wireless charging disabled.
Wired and wireless charging disabled.
Input for the rectified power measurement. See Section 9.3.16 for details.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
5
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
Table 7-1. Pin Functions (continued)
PIN
NAME
NO.
I/O
DESCRIPTION
ILIM
12
I/O
Programming pin for the over current limit. The total resistance from ILIM to GND (RILIM) sets the current limit.
The schematic shown in Figure 10-1 illustrates the RILIM as R1 + RFOD. Details can be found in Section 8.5
and Figure 10-1.
OUT
4
O
Output pin, delivers power to the load.
PGND
1, 20
RECT
18
O
Filter capacitor for the internal synchronous rectifier. Connect a ceramic capacitor to PGND. Depending on the
power levels, the value may be 4.7 μF to 22 μF.
13
I
Dual function pin: Temperature Sense (TS) and Control (CTRL) pin functionality.
For the TS functionality connect TS/CTRL to ground through a Negative Temperature Coefficient (NTC)
resistor. If an NTC function is not desired, connect to PGND with a 10-kΩ resistor. See Section 9.3.13 for
more details.
For the CTRL functionality pull below VCTRL-Low or pull above VCTRL-High to send an End Power Transfer
Packet. See Table 9-4 for more details.
PAD
—
TS/CTRL
—
Power ground
The exposed thermal pad should be connected to ground (PGND)
8 Specifications
8.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1) (2)
Input voltage
MIN
MAX
AC1, AC2
–0.8
20
RECT, COMM1, COMM2, OUT, CHG, CLAMP1,
CLAMP2
–0.3
20
AD, AD-EN
–0.3
30
BOOT1, BOOT2
–0.3
26
–0.3
7
(3)
EN1, EN2 , FOD, TS/CTRL, ILIM
UNIT
V
Input current
AC1, AC2
Output current
OUT
1.5
A
CHG
15
mA
Output sink current
2
1
A
Junction temperature, TJ
–40
150
°C
Storage temperature, Tstg
–65
150
°C
(1)
(2)
(3)
COMM1, COMM2
A(RMS)
All voltages are with respect to the VSS terminal, unless otherwise noted.
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating
Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
If EN1 or EN2 are subject to fast transient (>10V/10ns), current limiting resistors (1k to 10k ohms) should be added.
8.2 ESD Ratings
VALUE
V(ESD)
(1)
Electrostatic discharge
Human body model (HBM), per AEC Q100-002(1)
±2000
Charged device model (CDM), per AEC Q100-011
±500
UNIT
V
AEC Q100-002 indicates that HBM stressing must be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.
8.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
VRECT
6
Voltage
RECT
Submit Document Feedback
MIN
MAX
4
7
UNIT
V
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.3 Recommended Operating Conditions (continued)
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
UNIT
IRECT
Current through
internal rectifier
RECT
1.5
A
IOUT
Output current
OUT
1.5
A
VAD
Adapter voltage
AD
15
V
IAD-EN
Sink current
AD-EN
1
mA
ICOMM
COMMx sink current
COMM1, COMM2
500
mA
TJ
Junction temperature
125
°C
0
8.4 Thermal Information
BQ51013B-Q1
THERMAL METRIC(1)
RHL (VQFN)
UNIT
20 PINS
RθJA
Junction-to-ambient thermal resistance
37.2
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
30.0
°C/W
RθJB
Junction-to-board thermal resistance
14.0
°C/W
ψJT
Junction-to-top characterization parameter
0.4
°C/W
ψJB
Junction-to-board characterization parameter
13.9
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
3.3
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
8.5 Electrical Characteristics
over operating free-air temperature range, –40°C to 125°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
2.5
2.7
2.8
UNIT
VUVLO
Undervoltage lockout
VRECT: 0 V → 3 V
VHYS-UVLO
Hysteresis on UVLO
VRECT: 3 V → 2 V
VRECT-OVP
Input overvoltage threshold
VRECT: 5 V → 16 V
VHYS-OVP
Hysteresis on OVP
VRECT: 16 V → 5 V
0.15
V
VRECT-Th1
Dynamic VRECT Threshold 1
ILOAD < 0.1 x IIMAX (ILOAD rising)
7.08
V
VRECT-Th2
Dynamic VRECT Threshold 2
0.1 x IIMAX < ILOAD < 0.2 x IIMAX
(ILOAD rising)
6.28
V
VRECT-Th3
Dynamic VRECT Threshold 3
0.2 x IIMAX < ILOAD < 0.4 x IIMAX
(ILOAD rising)
5.53
V
VRECT-Th4
Dynamic VRECT Threshold 4
ILOAD > 0.4 x IIMAX (ILOAD rising)
5.11
V
VRECT-DPM
Rectifier undervoltage protection, restricts
IOUT at VRECT-DPM
VRECT-REV
Rectifier reverse voltage protection at the
output
0.25
14.5
15
V
V
15.5
V
3
3.1
3.2
V
7
8
9
V
ILOAD = 0 mA, 0°C ≤ TJ ≤ 85°C
8
10
mA
ILOAD = 300 mA,
0°C ≤ TJ ≤ 85°C
2
3
mA
20
35
µA
VRECT-REV = VOUT - VRECT,
VOUT = 10 V
QUIESCENT CURRENT
IRECT
Active chip quiescent current consumption
from RECT
IOUT
Quiescent current at the output when
wireless power is disabled (Standby)
VOUT = 5 V, 0°C ≤ TJ ≤ 85°C
ILIM SHORT CIRCUIT
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
7
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.5 Electrical Characteristics (continued)
over operating free-air temperature range, –40°C to 125°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
RILIM-SHORT
Highest value of ILIM resistance to ground
(RILIM) considered a fault (short). Monitored
for IOUT > 100 mA
tDGL-Short
Deglitch time transition from ILIM short to
IOUT disable
ILIM-SHORT,OK enables the ILIM short
IILIM_SHORT,OK comparator when IOUT is greater than this
value
IILIM_SHORT,OK
HYST
IOUT
MIN
TYP
RILIM: 200 Ω → 50 Ω. IOUT
latches off, cycle power to reset
MAX
UNIT
120
Ω
1
ILOAD: 0 mA → 200 mA
Hysteresis for ILIM-SHORT,OK comparator
ILOAD: 0 mA → 200 mA
Maximum output current limit, CL
Maximum ILOAD that will be
delivered for 1 ms when ILIM is
shorted
116
145
ms
165
30
mA
mA
2450
mA
OUTPUT
ILOAD = 1000 mA
4.92
5.00
5.04
ILOAD = 10 mA
4.94
5.01
5.06
Current programming factor for hardware
protection
RILIM = KILIM / IILIM, where IILIM is
the hardware current limit.
IOUT = 1 A
285
314
321
KIMAX
Current programming factor for the nominal
operating current
IIMAX = KIMAX / RILIM where
IMAX is the maximum normal
operating current.
IOUT = 1 A
IOUT
Current limit programming range
ICOMM
Current limit during WPC communication
tHOLD
Hold off time for the communication current
limit during start-up
VOUT-REG
Regulated output voltage
KILIM
262
IOUT < 300 mA
Iout + 50
320
380
AΩ
AΩ
1500
IOUT > 300 mA
V
mA
mA
440
1
mA
s
TS / CTRL FUNCTIONALITY
VTS-Bias
Internal TS Bias Voltage (VTS is the voltage
at the TS/CTRL pin, VTS-Bias is thet internal
bias voltage)
ITS-Bias < 100 µA (periodically
driven see tTS/CTRL)
VCOLD
Rising threshold
VTS-Bias: 50% → 60%
VCOLD-Hyst
Falling hysteresis
VTS-Bias: 60% → 50%
VHOT
Falling threshold
VTS-Bias: 20% → 15%
VHOT-Hyst
Rising hysteresis
VTS-Bias: 15% → 20%
VCTRL-High
Voltage on CTRL pin for a high
VCTRL-Low
Voltage on CTRL pin for a low
tTS/CTRL-Meas
Time period of TS/CTRL measurements
(when VTS-Bias is being driven internally)
tTS-Deglitch
Deglitch time for all TS comparators
RTS
Pullup resistor for the NTC network. Pulled
up to VTB-Bias
2
2.2
56.5
58.7
60.8 %VTS-Bias
2
%VTS-Bias
19.6
20.7 %VTS-Bias
3
%VTS-Bias
18.5
2.4
0.2
5
0
0.05
Synchronous to the
communication period
18
V
V
mV
24
ms
10
ms
20
22
kΩ
THERMAL PROTECTION
TJ-SD
Thermal shutdown temperature
TJ-Hys
Thermal shutdown hysteresis
155
°C
20
°C
OUTPUT LOGIC LEVELS ON CHG
VOL
Open-drain CHG pin
ISINK = 5 mA
IOFF
CHG leakage current when disabled
V CHG = 20 V
500
mV
1
µA
COMM PIN
8
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.5 Electrical Characteristics (continued)
over operating free-air temperature range, –40°C to 125°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
RDS(ON)
COMM1 and COMM2
VRECT = 2.6 V
IOFF
COMMx pin leakage current
VCOMM1 = 20 V, VCOMM2 = 20 V
MIN
TYP
MAX
1.5
UNIT
Ω
1
µA
CLAMP PIN
RDS(ON)
CLAMP1 and CLAMP2
0.8
Ω
ADAPTER ENABLE
VAD-Pres
VAD Rising threshold voltage
VAD 0 V → 5 V
VAD-PresH
VAD hysteresis
VAD 5 V → 0 V
IAD
Input leakage current
VRECT = 0 V, VAD = 5 V
RAD
Pullup resistance from AD-EN to OUT when
adapter mode is disabled and VOUT > VAD, VAD = 0 V, VOUT = 5 V
EN-OUT
VAD-Diff
Voltage difference between VAD and V AD-EN
VAD = 5 V, 0°C ≤ TJ ≤ 85°C
when adapter mode is enabled
3.5
3.6
3.8
400
V
mV
60
μA
200
350
Ω
3
4.5
5
V
80
100
135
SYNCHRONOUS RECTIFIER
IOUT-SR
IOUT at which the synchronous rectifier
enters half-synchronous mode, SYNC_EN
ILOAD 200 mA → 0 mA
IOUT-SRH
Hysteresis for IOUT,SR (full-synchronous
mode enabled)
ILOAD 0 mA → 200 mA
30
mA
VHS-DIODE
High-side diode drop when the rectifier is in
half-synchronous mode
IAC-VRECT = 250 mA and
TJ = 25°C
0.7
V
mA
EN1 AND EN2
VIL
Input low threshold for EN1 and EN2
VIH
Input high threshold for EN1 and EN2
RPD
EN1 and EN2 pulldown resistance
0.4
1.3
V
V
200
kΩ
ADC (WPC RELATED MEASUREMENTS AND COEFFICIENTS)
IOUT SENSE
Accuracy of the current sense over the load
IOUT = 750 mA - 1000 mA
range
–1.5%
0%
0.9%
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
9
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.6 Typical Characteristics
100
80
70
90
60
50
Efficiency (%)
Efficiency (%)
80
70
40
30
60
20
50
10
0
40
0
1
2
0
5
4
3
1
2
3
4
5
Power (W)
Power (W)
Input: RX AC power
Output: RX RECT power
Efficiency: Output Power / Input Power
Input: TX DC power
Output: RX RECT power
Efficiency: Output Power / Input Power
Figure 8-2. System Efficiency From DC Input to DC Output
Figure 8-1. Rectifier Efficiency
7.5
80
70
VRECT_RISING
7.0
VRECT_FALLING
60
VRECT (V)
Efficiency (%)
50
40
30
6.5
6.0
20
5.5
RILIM = 250 Ω
10
RILIM = 500 Ω
0
5.0
0
1
2
3
4
0
5
200
400
600
800
1000
1200
Iout (mA)
Power (W)
Input: TX DC power
Output: RX RECT power
Plot: Output Power / Input Power
Figure 8-3. Light Load System Efficiency Improvement Due to
Dynamic Efficiency Scaling Feature (1)
RILIM = 250 Ω
Figure 8-4. Impact of Load Current ( ILOAD) on Rectifier Voltage
(VRECT)
7.5
4.99
4.985
RILIM = 250 Ω
7.0
RILIM = 750 Ω
4.98
4.975
Vout(V)
VRECT (V)
6.5
4.97
4.965
6.0
4.96
4.955
5.5
4.95
5.0
0
200
400
600
800
1000
1200
4.945
0.0
IOUT (mA)
0.4
0.6
0.8
1.0
1.2
Output Current (A)
RILIM = 250 Ω and 750 Ω
Maximum Current = 1 A
Figure 8-5. Impact of Maximum Current setting (RILIM) on
Rectifier Voltage (VRECT)
10
0.2
Figure 8-6. Impact of Load Current on Output Voltage
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.6 Typical Characteristics (continued)
100.0
5.004
90.0
5.002
70.0
Vout (V)
Output Ripple (mV)
80.0
60.0
5.000
50.0
4.998
40.0
30.0
0.0
0.2
0.4
0.6
Load Current (A)
COUT = 1 µf
0.8
1.0
Without Communication
0
20
40
60
80
Temperature (°C)
100
120
Figure 8-8. VOUT vs Temperature
Figure 8-7. Impact of Load Current on Output Ripple
Figure 8-10. 1-A Load Step Full System Response
Figure 8-9. 1-A Instantaneous Load Dump (2)
VRECT
VOUT
Figure 8-11. 1-A Load Dump Full System Response
Figure 8-12. Rectifier Overvoltage Clamp (fop = 110 kHz)
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
11
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.6 Typical Characteristics (continued)
VTS/CTRL
VRECT
VRECT
VOUT
Figure 8-13. TS Fault
Figure 8-14. Adapter Insertion (VAD = 10 V)
VAD
VRECT
VRECT
VOUT
Figure 8-15. Adapter Insertion (VAD = 10 V) Illustrating BreakBefore-Make Operation
Figure 8-16. On-the-Go Enabled (VOTG = 3.5 V) (3)
IOUT
IOUT
VRECT
VRECT
VOUT
VOUT
Figure 8-17. BQ51013B-Q1 Typical Start-Up With a 1-A System
Load
12
Figure 8-18. Adaptive Communication Limit Event Where the
400-mA Current Limit is Enabled (IOUT-DC < 300 mA)
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
8.6 Typical Characteristics (continued)
IOUT
VRECT
VOUT
Figure 8-20. RX Communication Packet Structure
Figure 8-19. Adaptive Communication Limit Event Where the
Current Limit is IOUT + 50 mA (IOUT-DC > 300 mA)
1. Efficiency measured from DC input to the transmitter to DC output of the receiver. The BQ500210EVM-689
TX was used for these measurements. Measurement subject to change if an alternate TX is used.
2. Total droop experienced at the output is dependent on receiver coil design. The output impedance must be
low enough at that particular operating frequency in order to not collapse the rectifier below 5 V.
3. On-the-go mode is enabled by driving EN1 high. In this test, the external PMOS is connected between the
output of the BQ51013B-Q1 device and the AD pin; therefore, any voltage source on the output is supplied
to the AD pin.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
13
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
9 Detailed Description
9.1 Overview
A wireless system consists of a charging pad (transmitter, TX or primary) and the secondary-side equipment
(receiver, RX or secondary). There is a coil in the charging pad and in the secondary equipment which are
magnetically coupled to each other when the secondary is placed on the primary. Power is then transferred
from the transmitter to the receiver through coupled inductors (effectively an air-core transformer). Controlling
the amount of power transferred is achieved by sending feedback (error signal) communication to the primary (to
increase or decrease power).
The receiver communicates with the transmitter by changing the load seen by the transmitter. This load variation
results in a change in the transmitter coil current, which is measured and interpreted by a processor in
the charging pad. The communication is digital; packets are transferred from the receiver to the transmitter.
Differential bi-phase encoding is used for the packets. The bit rate is 2-kbps.
Various types of communication packets have been defined. These include identification and authentication
packets, error packets, control packets, end power packets, and power usage packets.
The transmitter coil stays powered off most of the time. It occasionally wakes up to see if a receiver is present.
When a receiver authenticates itself to the transmitter, the transmitter will remain powered on. The receiver
maintains full control over the power transfer using communication packets.
Power
AC to DC
Drivers
BQ51013B-Q1
Voltage/
Current
Conditioning
Rectification
System
Load
Communication
Controller
V/I
Sense
Battery
Charger
Controller
LI-Ion
Battery
BQ500212A
Transmitter
Receiver
Figure 9-1. WPC Wireless Power System Indicating the Functional Integration of the BQ51013B-Q1
14
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
9.2 Functional Block Diagram
RECT
,
OUT
VOUT,FB
+
_
+
_
VREF,ILIM
VILIM
VOUT,REG
VREF,IABS
VIABS,FB
+
_
VIN,FB
VIN,DPM
+
_
ILIM
AD
+
_
VREFAD,OVP
BOOT2
+
_
BOOT1
VREFAD,UVLO
AD-EN
AC1
AC2
Sync
Rectifier
Control
VREF,TS-BIAS
COMM1
COMM2
DATA_
OUT
CLAMP1
ADC
VBG,REF
VIN,FB
VOUT,FB
VILIM
VIABS,FB
VIABS,REF
VIC,TEMP
Digital Control
CLAMP2
VFOD
+
_
TS_COLD
TS_HOT
FOD
+
_
+
_
TS/CTRL
TS_DETECT
+
_
VREF_100MV
VFOD
CHG
EN1
200k:
VRECT
VOVP,REF
+
_
OVP
EN2
200k:
PGND
9.3 Feature Description
9.3.1 Details of a Qi Wireless Power System and BQ51013B-Q1 Power Transfer Flow Diagrams
The BQ51013B-Q1 integrates a fully compliant WPC v1.2 communication algorithm in order to streamline
receiver designs (no extra software development required). Other unique algorithms such as Dynamic Rectifier
Control are also integrated to provide best-in-class system performance. This section provides a high level
overview of these features by illustrating the wireless power transfer flow diagram from start-up to active
operation.
During start-up operation, the wireless power receiver must comply with proper handshaking to be granted a
power contract from the TX. The TX will initiate the handshake by providing an extended digital ping. If an RX is
present on the TX surface, the RX will then provide the signal strength, configuration and identification packets
to the TX (see volume 1 of the WPC specification for details on each packet). These are the first three packets
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
15
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
sent to the TX. The only exception is if there is a true shutdown condition on the EN1/EN2, AD, or TS/CTRL
pins where the RX will shut down the TX immediately. See Table 9-4 for details. Once the TX has successfully
received the signal strength, configuration and identification packets, the RX will be granted a power contract
and is then allowed to control the operating point of the power transfer. With the use of the BQ51013B-Q1
Dynamic Rectifier Control algorithm, the RX will inform the TX to adjust the rectifier voltage above 7 V prior to
enabling the output supply. This method enhances the transient performance during system start-up. See Figure
9-2 for the start-up flow diagram details.
TX Powered
without RX
Active
TX Extended Digital Ping
EN1/EN2/AD/TS/CTRL
EPT Condition?
YES
Send EPT packet with
reason value
NO
Identification &
Configuration & SS, Received
by TX?
NO
YES
Power Contract Established.
All proceeding control is
dictated by the RX.
VRECT < VRECT-TH1 ?
YES
Send control error packet to
increase VRECT
NO
Startup operating point
established. Enable the RX
output.
RX
Active Power
Transfer Stage
Figure 9-2. Wireless Power Start-Up Flow Diagram
Once the start-up procedure has been established, the RX enters the active power transfer stage. This is
considered the “main loop” of operation. The Dynamic Rectifier Control algorithm determines the rectifier voltage
target based on a percentage of the maximum output current level setting (set by KIMAX and the ILIM resistance
to GND). The RX sends control error packets in order to converge on these targets. As the output current
changes, the rectifier voltage target will dynamically change. The feedback loop of the WPC system is relatively
slow where it can take up to 90 ms to converge on a new rectifier voltage target. It should be understood that the
instantaneous transient response of the system is open loop and dependent on the RX coil output impedance at
that operating point. More details on this is covered in the section Receiver Coil Load-Line Analysis. The “main
loop” also determines if any conditions in Table 9-4 are true in order to discontinue power transfer. See Figure
9-3 which illustrates the active power transfer loop.
16
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
RX
Active Power
Transfer Stage
RX Shutdown
conditions per
the EPT Table?
YES
Send EPT packet with
reason value
YES
VRECT target = VRECT-Th1.
Send control error packets
to converge.
YES
VRECT target = VRECT-Th2.
Send control error packets
to converge.
YES
VRECT target = VRECT-Th3.
Send control error packets
to converge.
TX Powered
without RX
Active
NO
IOUT < 10% of IIMAX?
NO
IOUT < 20% of IIMAX?
NO
IOUT < 40% of IIMAX?
NO
VRECT target = VRECT-Th4.
Send control error packets
to converge.
Measure Rectified Power
and Send Value to TX
Figure 9-3. Active Power Transfer Flow Diagram
Another requirement of the WPC v1.2 specification is to send the measured received power. This task is enabled
on the device by measuring the voltage on the FOD pin which is proportional to the output current and can be
scaled based on the choice of the resistor to ground on the FOD pin.
9.3.2 Dynamic Rectifier Control
The Dynamic Rectifier Control algorithm offers the end system designer optimal transient response for a given
maximum output current setting. This is achieved by providing enough voltage headroom across the internal
regulator at light loads in order to maintain regulation during a load transient. The WPC system has a relatively
slow global feedback loop where it can take more than 90 ms to converge on a new rectifier voltage target.
Therefore, the transient response is dependent on the loosely coupled transformers output impedance profile.
The Dynamic Rectifier Control allows for a 2 V change in rectified voltage before the transient response will be
observed at the output of the internal regulator (output of the BQ51013B-Q1). A 1-A application allows up to a
1.5-Ω output impedance. The Dynamic Rectifier Control behavior is illustrated in Impact of Load Current ( ILOAD)
on Rectifier Voltage (VRECT) where RILIM is set to 220 Ω.
9.3.3 Dynamic Efficiency Scaling
The Dynamic Efficiency Scaling feature allows for the loss characteristics of the BQ51013B-Q1 to be scaled
based on the maximum expected output power in the end application. This effectively optimizes the efficiency for
each application. This feature is achieved by scaling the loss of the internal LDO based on a percentage of the
maximum output current. Note that the maximum output current is set by the KIMAX term and the RILIM resistance
(where RILIM = KIMAX / IMAX). The flow diagram shown in Figure 9-3 illustrates how the rectifier is dynamically
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
17
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
controlled (Dynamic Rectifier Control) based on a fixed percentage of the IMAX setting. Table 9-1 summarizes
how the rectifier behavior is dynamically adjusted based on two different RILIM settings.
Table 9-1. Dynamic Efficiency Scaling
OUTPUT CURRENT
PERCENTAGE
RILIM = 500 Ω
IMAX = 0.5 A
RILIM = 220 Ω
IMAX = 1.14 A
VRECT
0 to 10%
0 A to 0.05 A
0 A to 0.114 A
7.08 V
10 to 20%
0.05 A to 0.1 A
0.114 A to 0.227 A
6.28 V
20 to 40%
0.1 A to 0.2 A
0.227 A to 0.454 A
5.53 V
>40%
> 0.2 A
> 0.454 A
5.11 V
Impact of Maximum Current setting (RILIM) on Rectifier Voltage (VRECT) illustrates the shift in the Dynamic
Rectifier Control behavior based on the two different RILIM settings. With the rectifier voltage (VRECT) being the
input to the internal LDO, this adjustment in the Dynamic Rectifier Control thresholds will dynamically adjust the
power dissipation across the LDO where:
(
)
PDIS = VRECT - VOUT × IOUT
(1)
Light Load System Efficiency Improvement Due to Dynamic Efficiency Scaling Feature (1) illustrates how the
system efficiency is improved due to the Dynamic Efficiency Scaling feature. Note that this feature balances
efficiency with optimal system transient response.
9.3.4 RILIM Calculations
The BQ51013B-Q1 includes a means of providing hardware overcurrent protection by means of an analog
current regulation loop. The hardware current limit provides an extra level of safety by clamping the maximum
allowable output current (current compliance). The RILIM resistor size also sets the thresholds for the dynamic
rectifier levels and thus providing efficiency tuning per each application’s maximum system current. The
calculation for the total RILIM resistance is as follows:
K IM A X
R IL IM =
IM A X
K IL IM
I IL IM = 1 . 2 ´ I M A X =
R IL IM
R IL IM = R 1 + R F O D
(2)
where
•
•
IMAX is the expected maximum output current during normal operation.
IILIM is the hardware over current limit.
When referring to the application diagram shown in Figure 10-1, RILIM is the sum of RFOD and R1 (the total
resistance from the ILIM pin to GND).
9.3.5 Input Overvoltage
If the input voltage suddenly increases in potential (for example, due to a change in position of the equipment
on the charging pad), the voltage-control loop inside the BQ51013B-Q1 becomes active, and prevents the output
from going beyond VOUT-REG. The receiver then starts sending back error packets to the transmitter every 30 ms
until the input voltage comes back to the VRECT-REG target, and then maintains the error communication every
250 ms.
If the input voltage increases in potential beyond VRECT-OVP, the device switches off the LDO and communicates
to the primary to bring the voltage back to VRECT-REG. In addition, a proprietary voltage protection circuit is
activated by means of CCLAMP1 and CCLAMP2 that protects the device from voltages beyond the maximum rating
of the device.
18
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
9.3.6 Adapter Enable Functionality and EN1/EN2 Control
Figure 10-6 is an example application that shows the BQ51013B-Q1 used as a wireless power receiver that
can power mutliplex between wired or wireless power for the down-system electronics. In the default operating
mode, pins EN1 and EN2 are low, which activates the adapter enable functionality. In this mode, if an adapter is
not present the AD pin will be low, and AD-EN pin will be pulled to the higher of the OUT and AD pins so that the
PMOS between OUT and AD will be turned off. If an adapter is plugged in and the voltage at the AD pin goes
above V AD-EN , then wireless charging is disabled and the AD-EN pin will be pulled approximately VAD below
the AD pin to connect AD to the secondary charger. The difference between AD and AD-EN is regulated to a
maximum of VAD-Diff to ensure the VGS of the external PMOS is protected.
The EN1 and EN2 pins include internal pulldown resistors (RPD), so that if these pins are not connected
BQ51013B-Q1 defaults to AD-EN control mode. However, these pins can be pulled high to enable other
operating modes. If the pins are pulled high or controlled by drivers and are subject to fast transient (>10V/10ns)
higher than ~ 8V it is recommended that current limit resistors (1k to 10k ohms) be added in series with the pins.
See Table 9-2:
Table 9-2. Adapter Enable Functionality
EN1
EN2
RESULT
0
0
Adapter control enabled. If adapter is present then secondary charger is powered by adapter, otherwise wireless
charging is enabled when wireless power is available. Communication current limit is enabled.
0
1
Disables communication current limit.
1
0
AD-EN is pulled low, whether or not adapter voltage is present. This feature can be used for USB OTG applications.
1
1
Adapter and wireless charging are disabled, power will not be delivered by the OUT pin in this mode.
Table 9-3. EN1/EN2 Control
EN1
(1)
(2)
EN2
WIRELESS POWER
WIRED POWER
OTG MODE
ADAPTIVE COMMUNICATION LIMIT
EPT
0
0
Enabled
Priority(1)
Disabled
Enabled
Not Sent to TX
0
1
Priority(1)
Enabled
Disabled
Disabled
Not Sent to TX
N/A
EPT 0x00, Unknown
N/A
EPT 0x01,
Charge Complete
1
0
Disabled
Enabled
Enabled(2)
1
1
Disabled
Disabled
Disabled
If both wired and wireless power are present, wired or wireless is given priority based on EN2.
Allows for a boost-back supply to be driven from the output terminal of the RX to the adapter port through the external back-to-back
PMOS FET.
As described in Table 9-3, when EN1 is low, both wired and wireless power are useable. If both are present,
priority is set between wired and wireless by EN2. When EN1 is high, wireless power is disabled and wired
power functionality is set by EN2. When EN1 is high but EN2 is low, wired power is enabled if present.
Additionally, USB OTG mode is active. In USB OTG mode, a charger connected to the OUT pin can power the
AD pin. Note that EN1 must be pulled high from an active source (microcontroller). Finally, pulling both EN1 and
EN2 high disables both wired and wireless charging.
Note
It is required to connect a back-to-back PMOS between AD and OUT so that voltage is blocked in
both directions. Also, when AD mode is enabled no load can be pulled from the RECT pin as this
could cause an internal device overvoltage in BQ51013B-Q1.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
19
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
9.3.7 End Power Transfer Packet (WPC Header 0x02)
The WPC allows for a special command for the receiver to terminate power transfer from the transmitter termed
End Power Transfer (EPT) packet. Table 9-4 specifies the v1.2 reasons column and their corresponding data
field value. The condition column corresponds to the methodology used by BQ51013B-Q1 to send equivalent
message.
Table 9-4. End Power Transfer Packet
MESSAGE
VALUE
CONDITION
Unknown
0x00
AD > VAD-Pres, or = , or TS/CTRL > VCTRLHigh, or TS > VCOLD
Charge Complete
0x01
=
Internal Fault
0x02
TJ > 150°C or RILIM < 100 Ω
Overtemperature
0x03
TS < VHOT, or TS/CTRL < VCTRL-Low
Overvoltage
0x04
VRECT target does not converge
Overcurrent
0x05
Not sent
Battery Failure
0x06
Not sent
Reconfigure
0x07
Not sent
No Response
0x08
Not sent
9.3.8 Status Outputs
The BQ51013B-Q1 has one status output, CHG. This output is an open-drain NMOS device that is rated to 20
V. The open-drain FET connected to the CHG pin will be turned on whenever the output of the power supply is
enabled. The output of the power supply will not be enabled if the VRECT-REG does not converge at the no-load
target voltage.
9.3.9 WPC Communication Scheme
The WPC communication uses a modulation technique termed “back-scatter modulation” where the receiver coil
is dynamically loaded in order to provide amplitude modulation of the transmitter's coil voltage and current. This
scheme is possible due to the fundamental behavior between two loosely coupled inductors (here between the
TX and RX coils). This type of modulation can be accomplished by switching in and out a resistor at the output of
the rectifier, or by switching in and out a capacitor across the AC1/AC2 net. Figure 9-4 shows how to implement
resistive modulation.
CRES1
AC1
VRECT
R MOD
COIL
C RES2
AC2
GND
Figure 9-4. Resistive Modulation
Figure 9-5 shows how to implement capacitive modulation.
20
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
CRES1
AC1
VRECT
C MOD
COIL
C RES2
AC2
GND
Figure 9-5. Capacitive Modulation
The amplitude change in the TX coil voltage or current can be detected by the transmitter's decoder. The
resulting signal observed by the TX is shown in Figure 9-6.
Power
AC to DC
BQ51013B-Q1
Drivers
Voltage/
Current
Conditioning
Rectification
System
Load
Communication
Controller
Battery
Charger
Controller
V/I
Sense
LI-Ion
Battery
BQ500212A
0
1
0
1
0
Figure 9-6. TX Coil Voltage/Current
The WPC protocol uses a differential bi-phase encoding scheme to modulate the data bits onto the TX coil
voltage/current. Each data bit is aligned at a full period of 0.5 ms (tCLK) or 2 kHz. An encoded ONE results in
two transitions during the bit period and an encoded ZERO results in a single transition. See Figure 9-7 for an
example of the differential bi-phase encoding.
Figure 9-7. Differential Bi-Phase Encoding Scheme (WPC Volume 1: Low Power, Part 1 Interface
Definition)
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
21
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
The bits are sent LSB first and use an 11-bit asynchronous serial format for each portion of the packet. This
includes one start bit, n-data bytes, a parity bit, and a single stop bit. The start bit is always ZERO and the parity
bit is odd. The stop bit is always ONE. Figure 9-8 shows the details of the asynchronous serial format.
Figure 9-8. Asynchronous Serial Formatting (WPC Volume 1: Low Power, Part 1 Interface Definition)
Each packet format is organized as shown in Figure 9-9.
Preamble
Header
Message
Checksum
Figure 9-9. Packet Format (WPC Volume 1: Low Power, Part 1 Interface Definition)
RX Communication Packet Structure shows an example waveform of the receiver sending a rectified power
packet (header 0x04).
9.3.10 Communication Modulator
The BQ51013B-Q1 device provides two identical, integrated communication FETs which are connected to the
pins COMM1 and COMM2. These FETs are used for modulating the secondary load current which allows the
BQ51013B-Q1 to communicate error control and configuration information to the transmitter. Figure 9-10 shows
how the COMMx pins can be used for resistive load modulation. Each COMMx pin can handle at most a 24-Ω
communication resistor. Therefore, if a COMMx resistor between 12 Ω and 24 Ω is required, COMM1 and
COMM2 pins must be connected in parallel. The BQ51013B-Q1 device does not support a COMMx resistor less
than 12 Ω.
RECTIFIER
24 :
COMM1
24 :
COMM2
COMM_DRIVE
Figure 9-10. Resistive Load Modulation
In addition to resistive load modulation, the BQ51013B-Q1 is also capable of capacitive load modulation as
shown in Figure 9-11. In this case, a capacitor is connected from COMM1 to AC1 and from COMM2 to AC2.
When the COMMx switches are closed there is effectively a 22 nF capacitor connected between AC1 and AC2.
Connecting a capacitor in between AC1 and AC2 modulates the impedance seen by the coil, which will be
reflected in the primary as a change in current.
22
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
AC1
AC2
47 nF
47 nF
COMM1
COMM2
COMM_DRIVE
Figure 9-11. Capacitive Load Modulation
9.3.11 Adaptive Communication Limit
The Qi communication channel is established through backscatter modulation as described in the previous
sections. This type of modulation takes advantage of the loosely coupled inductor relationship between the RX
and TX coils. Essentially, the switching in-and-out of the communication capacitor or resistor adds a transient
load to the RX coil in order to modulate the TX coil voltage and current waveform (amplitude modulation). The
consequence of this technique is that a load transient (load current noise) from the mobile device has the same
signature. To provide noise immunity to the communication channel, the output load transients must be isolated
from the RX coil. The proprietary feature Adaptive Communication Limit achieves this by dynamically adjusting
the current limit of the regulator. When the regulator is put in current limit, any load transients will be offloaded to
the battery in the system.
Note that this requires the battery charger device to have input voltage regulation (weak adapter mode). The
output of the RX appears as a weak supply if a transient occurs above the current limit of the regulator.
The Adaptive Communication Limit feature has two current limit modes and is detailed in Table 9-5.
Table 9-5. Adaptive Communication Limit
IOUT
COMMUNICATION CURRENT LIMIT
< 300 mA
Fixed 400 mA
> 300 mA
IOUT + 50 mA
The first mode is illustrated in Adaptive Communication Limit Event Where the 400-mA Current Limit is Enabled
(IOUT-DC < 300 mA). In this plot, an output load pulse of 300 mA is periodically introduced on a DC current level
of 200 mA. Therefore, the 400 mA current limit is enabled. The pulses on VRECT indicate that a communication
packet event is occurring. When the output load pulse occurs, the regulator limits the pulse to a constant 400 mA
and, therefore, preserves communication. Note that VOUT drops to 4.5 V instead of GND. A charger device with
an input voltage regulation set to 4.5 V allows this to occur by offloading the load transient support to the mobile
device’s battery.
The second mode is illustrated in Adaptive Communication Limit Event Where the Current Limit is IOUT + 50
mA (IOUT-DC > 300 mA). In this plot, an output pulse of 200 mA is periodically introduced on a DC current level
of 400 mA. Therefore, the tracking current mode (IOUT + 50 mA) is enabled. In this mode, the BQ51013B-Q1
measures the active output current and sets the regulator's current limit 50 mA above this measurement. When
the load pulse occurs during a communication packet event, the output current is regulated to 450 mA. As the
communication packet event has finished the output load is allowed to increase. Note that during the time the
regulator is in current limit VOUT is reduced to 4.5 V and 5 V when not in current limit.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
23
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
9.3.12 Synchronous Rectification
The BQ51013B-Q1 provides an integrated, self-driven synchronous rectifier that enables high-efficiency AC to
DC power conversion. The rectifier consists of an all NMOS H-Bridge driver where the backgates of the diodes
are configured to be the rectifier when the synchronous rectifier is disabled. During the initial start-up of the
WPC system the synchronous rectifier is not enabled. At this operating point, the DC rectifier voltage is provided
by the diode rectifier. Once VRECT is greater than VUVLO, half synchronous mode will be enabled until the load
current surpasses IBAT-SR. Above IBAT-SR the full synchronous rectifier stays enabled until the load current drops
back below the hysteresis level (IBAT-SRH) where half-synchronous mode is enabled re-enabled.
9.3.13 Temperature Sense Resistor Network (TS)
The BQ51013B-Q1 includes a ratiometric external temperature sense function. The temperature sense function
has two ratiometric thresholds which represent a hot and cold condition. An external temperature sensor is
recommended in order to provide safe operating conditions for the receiver product. This pin is best used for
monitoring the surface that can be exposed to the end user (place the NTC resistor closest to where the user
would physically contact the end product).
Figure 9-12 allows for any NTC resistor to be used with the given VHOT and VCOLD thresholds.
VTSB
20 lQ
VTSB
R2
20 lQ
TS/CTRL
R2
TS/CTRL
R1
R1
R3
C3
NTC
C3
NTC
Figure 9-12. NTC Circuit Options For Safe Operation of the Wireless Receiver Power Supply
The resistors R1 and R3 can be solved by resolving the system of equations at the desired temperature
thresholds. The two equations are:
(
(
)
)
æ R R
+ R1 ö÷
ç
3
NTC TCOLD
ç
÷
+ R1 ÷
ç R 3 + R NTC
TCOLD
ø ´100
%VCOLD = è
æ R R
ö
R
+
ç
3
NTC TCOLD
1 ÷
ç
÷ + R2
+ R1 ÷
ç R 3 + R NTC
TCOLD
è
ø
)
)
æ R R
+ R1 ) ö÷
ç
3 ( NTC THOT
ç
÷
+ R1 )÷
ç R 3 + (R NTC
THOT
ø ´100
%VHOT = è
æ R R
ö
R
+
)
(
ç
3
NTC THOT
1 ÷
ç
÷ + R2
R
R
R
+
+
ç 3 ( NTC
÷
)
1
THOT
è
ø
(
(
(3)
Where:
24
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
R NTC
SLUSEE3 – JULY 2021
TCOLD
R NTC
THOT
bæçç 1
-1 ö÷÷
= R oe è TCOLD To ø
bæçç 1
-1 ö÷÷
= R oe è THOT To ø
(4)
where
•
•
•
TCOLD and THOT are the desired temperature thresholds in degrees Kelvin.
RO is the nominal resistance.
β is the temperature coefficient of the NTC resistor.
R2 is fixed at 20 kΩ. An example solution is provided:
• R1 = 4.23 kΩ
• R3 = 66.8 kΩ
where the chosen parameters are:
•
•
•
•
•
•
%VHOT = 19.6%
%VCOLD = 58.7%
TCOLD = –10°C
THOT = 100°C
β = 3380
RO = 10 kΩ
The plot of the percent VTSB vs. temperature is shown in Figure 9-13:
Figure 9-13. Example Solution for an NTC Resistor with RO = 10 kΩ and β = 3380
Figure 9-14 illustrates the periodic biasing scheme used for measuring the TS state. An internal TS_READ
signal enables the TS bias voltage (VTS-Bias) for 24 ms. During this period, the TS comparators are read (with
tTS deglitch) and appropriate action is taken based on the temperature measurement. After this 24-ms period
has elapsed, the TS_READ signal goes low, which causes the TS/CTRL pin to become high impedance. During
the next 35 ms (priority packet period) or 235 ms (standard packet period), the TS voltage is monitored and
compared to VCTRL-HI. If the TS voltage is greater than VCTRL-HI then a secondary device is driving the TS/CTRL
pin and a CTRL = ‘1’ is detected.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
25
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
24 ms
240 ms
TS_READ
Tracks comm packet
rate, typically 240 ms
when standard error
packets are sent.
TS pin is Hi-Z - LW¶V
monitored to see
whether some other
device is driving the TS
pin.
10 ms deglitch on all TS
comps
Figure 9-14. Timing Diagram For TS Detection Circuit
9.3.14 3-State Driver Recommendations for the TS/CTRL Pin
The TS/CTRL pin offers three functions with one 3-state driver interface:
•
•
•
NTC temperature monitoring
Over-Temperature Fault
End Power Transfer 0x00 (EPT Unknown)
A 3-state driver can be implemented with the circuit in Figure 9-15 and the use of two GPIO connections. M3 and
M4 and both resistors are external components.
BAT
TERM
BQ51013B-Q1
GPIO
System
Controller
TS/CTRL
FAULT
GPIO
Figure 9-15. 3-State Driver For TS/CTRL
Note that the signals TERM and FAULT are given by two GPIOs. The truth table for this circuit is found in Table
9-6:
Table 9-6. Truth Table
TERM
FAULT
F (Result)
1
0
High Impedance (Normal Mode)
0
0
End Power Transfer 0x00
1
1
End Power Transfer 0x03
The default setting is TERM / FAULT = 1 / 0. In this condition, the TS-CTRL net is high impedance (high-z) and
the NTC function is allowed to operate, normal operation. When TERM / FAULT = 1 /1 the TS-CTRL pin is pulled
to GND and the RX is shutdown with End Power Transfer Over Temperature sent to TX. When TERM / FAULT =
26
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
0 / 0, the TS-CTRL pin is pulled to the battery and the RX is shutdown with End Power Transfer Unknown sent to
the TX.
9.3.15 Thermal Protection
The BQ51013B-Q1 includes a thermal shutdown protection. If the die temperature reaches TJ-SD, the LDO is
shut off to prevent any further power dissipation. In this case BQ51013B-Q1 will send an EPT message of
internal fault (0x02). Once the temperature falls TJ-Hys below TJ-SD, operation can continue.
9.3.16 WPC v1.2 Compliance – Foreign Object Detection
The BQ51013B-Q1 is a WPC v1.2 compatible device. In order to enable a Power Transmitter to monitor the
power loss across the interface as one of the possible methods to limit the temperature rise of Foreign Objects,
the BQ51013B-Q1 reports its Received Power to the Power Transmitter. The Received Power equals the power
that is available from the output of the Power Receiver plus any power that is lost in producing that output
power (the power loss in the Secondary Coil and series resonant capacitor, the power loss in the Shielding of
the Power Receiver, the power loss in the rectifier). In the WPC1.2 specification, foreign object detection (FOD)
is enforced. This means the BQ51013B-Q1 will send received power information with known accuracy to the
transmitter.
WPC v1.2 defines Received Power as “the average amount of power that the Power Receiver receives through
its Interface Surface, in the time window indicated in the Configuration Packet”.
To receive certification as a WPC v1.2 receiver, the Device Under Test (DUT) is tested on a Reference
Transmitter whose transmitted power is calibrated, the receiver must send a received power such that:
0 > (TX PWR)REF – (RX PWR out)DUT > –375 mW
(5)
This 375-mW bias ensures that system will remain interoperable.
WPC v1.2 Transmitter is tested to see if it can detect reference Foreign Objects with a Reference receiver.
WPC v1.2 Specification will allow much more accurate sensing of Foreign Objects.
9.3.17 Receiver Coil Load-Line Analysis
When choosing a receiver coil, TI recommends analyzing the transformer characteristics between the primary
coil and receiver coil through load-line analysis. This will capture two important conditions in the WPC system:
•
•
Operating point characteristics in the closed loop of the WPC system.
Instantaneous transient response prior to the convergence of the new operating point.
An example test configuration for conducting this analysis is shown in Figure 9-16:
CP
VIN
CS
LP
LS
A
CD
CB
V
RL
Figure 9-16. Load-Line Analysis Test Bench
Where:
• VIN is a square-wave power source that should have a peak-to-peak operation of 19 V.
• CP is the primary series resonant capacitor (for example, 100 nF for Type A1 coil).
• LP is the primary coil of interest (such as, Type A1).
• LS is the secondary coil of interest.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
27
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
•
•
•
•
•
•
CS is the series resonant capacitor chosen for the receiver coil under test.
CD is the parallel resonant capacitor chosen for the receiver coil under test.
CB is the bulk capacitor of the diode bridge (voltage rating should be at least 25 V and capacitance value of at
least 10 µF)
V is a Kelvin connected voltage meter
A is a series ammeter
RL is the load of interest
TI recommends that the diode bridge be constructed of Schottky diodes.
The test procedure is as follows
• Supply a 19-V AC signal to LP starting at a frequency of 210 kHz
• Measure the resulting rectified voltage from no load to the expected full load
• Repeat the above steps for lower frequencies (stopping at 110 kHz)
An example load-line analysis is shown in Figure 9-17:
20
18
115 kHz
125 kHz
16
130 kHz
VRECT (V)
14
135 kHz
140 kHz
12
150 kHz
160 kHz
10
175 kHz
8
6
4
2
Ping voltage
1 A load operating point
1 A load step droop
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
LOAD (A)
Figure 9-17. Example Load-Line Results
What Figure 9-17 conveys about the operating point is that a specific load and rectifier target condition
consequently results in a specific operating frequency (for the type A1 TX). For example, at 1 A the dynamic
rectifier target is 5.15 V. Therefore, the operating frequency will be from 150 kHz to 160 kHz in the above
example. This is an acceptable operating point. If the operating point ever falls outside the WPC frequency range
(110 kHz – 205 kHz), the system will never converge and will become unstable.
In regards to transient analysis, there are two major points of interest:
• Rectifier voltage at the ping frequency (175 kHz).
• Rectifier voltage droop from no load to full load at the constant operating point.
In this example, the ping voltage will be approximately 5 V. This is above the UVLO of the BQ51013B-Q1
and, therefore, start-up in the WPC system can be ensured. If the voltage is near or below the UVLO at this
frequency, then start-up in the WPC system may not occur.
If the maximum load step is 1 A, the droop in this example will be approximately 1 V (using the 140 kHz
load-line). To analyze the droop, locate the load-line that starts at 7 V at no-load. Follow this load-line to the
maximum load expected and take the difference between the 7-V no-load voltage and the full-load voltage at
that constant frequency. Ensure that the full-load voltage at this constant frequency is above 5 V. If it descends
below 5 V, the output of the power supply will also droop to this level. This type of transient response analysis is
necessary due to the slow feedback response of the WPC system. This simulates the step response prior to the
WPC system adjusting the operating point.
28
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
Note
Coupling between the primary and secondary coils will worsen with misalignment of the secondary
coil. Therefore, it is recommended to re-analyze the load-lines at multiple misalignments to determine
where, in planar space, the receiver will discontinue operation.
See Table 10-1 for recommended RX coils.
9.4 Device Functional Modes
The operational modes of the BQ51013B-Q1 are described in the Section 9.3. The BQ51013B-Q1 has
several functional modes. Start-up refers to the initial power transfer and communication between the receiver
(BQ51013B-Q1 circuit) and the transmitter. Power transfer refers to any time that the TX and RX are
communicating and power is being delivered from the TX to the RX. Power transfer termination occurs when the
RX is removed from the TX, power is removed from the TX, or the RX requests power transfer termination.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
29
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
10 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification,
and TI does not warrant its accuracy or completeness. TI’s customers are responsible for
determining suitability of components for their purposes, as well as validating and testing their design
implementation to confirm system functionality.
10.1 Application Information
The BQ51013B-Q1 is a fully integrated wireless power receiver in a single device. The device complies with the
WPC v1.2 specifications for a wireless power receiver. When paired with a WPC v1.2 compliant transmitter, it
can provide up to 5 W of power. There are several tools available for the design of the system. These tools may
be obtained by checking the product page at www.ti.com/product/BQ51013B.
10.2 Typical Applications
10.2.1 BQ51013B-Q1 Wireless Power Receiver Used as a Power Supply
The following application discussion covers the requirements for setting up the BQ51013B-Q1 in a Qi-compliant
system for use as a power supply.
System
Load
AD-EN
AD
OUT
CCOMM1
C4
COMM1
CBOOT1
BOOT1
C1
AC1
C3
COIL
BQ51013B-Q1
C2
D1
ROS
RECT
R4
HOST
TS/CTRL
AC2
NTC
BOOT2
CBOOT2
COMM2
CHG
CLAMP2
EN1
Bi-State
CLAMP1
EN2
Bi-State
CCOMM2
CCLAMP2
CCLAMP1
ILIM
R1
FOD
Tri-State
PGND
RFOD
Figure 10-1. BQ51013B-Q1 Used as a Wireless Power Receiver and Power Supply for System Loads
10.2.1.1 Design Requirements
This application is for a system that has varying loads from less than 100 mA up to 1 A. It must work with
any Qi-certified transmitter. There is no requirement for any external thermal measurements. An LED indication
is required to indicate an active power supply. Each of the components from the application drawing will be
examined.
30
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
10.2.1.2 Detailed Design Procedure
10.2.1.2.1 Using The BQ51013B-Q1 as a Wireless Power Supply: (See Figure 10-1)
Figure 10-6 is the schematic of a system which uses the BQ51013B-Q1 as a power supply while power
multiplexing the wired (adapter) port.
When the system shown in Figure 10-1 is placed on the charging pad, the receiver coil is inductively coupled to
the magnetic flux generated by the coil in the charging pad which consequently induces a voltage in the receiver
coil. The internal synchronous rectifier feeds this voltage to the RECT pin which has the filter capacitor C3.
The BQ51013B-Q1 identifies and authenticates itself to the primary using the COMM pins by switching on and
off the COMM FETs and hence switching in and out CCOMM. If the authentication is successful, the transmitter
will remain powered on. The BQ51013B-Q1 measures the voltage at the RECT pin, calculates the difference
between the actual voltage and the desired voltage VRECT-REG, (threshold 1 at no load) and sends back error
packets to the primary. (Dynamic VRECT Thresholds are shown in the Section 8.5 table.) This process goes on
until the input voltage settles at VRECT-REG. During a load transient, the dynamic rectifier algorithm will set the
targets specified by VRECT-REG thresholds 1, 2, 3, and 4. This algorithm is termed Dynamic Rectifier Control and
is used to enhance the transient response of the power supply.
During power up, the LDO is held off until the VRECT-REG threshold 1 converges. The voltage control loop
ensures that the output voltage is maintained at VOUT-REG to power the system. The BQ51013B-Q1 meanwhile
continues to monitor the input voltage, and maintains sending error packets to the primary every 250 ms. If
a large overshoot occurs, the feedback to the primary speeds up to every 32 ms in order to converge on an
operating point in less time.
10.2.1.2.2 Series and Parallel Resonant Capacitor Selection
Shown in Figure 10-1, the capacitors C1 (series) and C2 (parallel) make up the dual resonant circuit with
the receiver coil. These two capacitors must be sized correctly per the WPC v1.2 specification. Figure 10-2
illustrates the equivalent circuit of the dual resonant circuit:
C1 (Cs)
>•[
C2 (Cd)
Figure 10-2. Dual Resonant Circuit With the Receiver Coil
The Power Receiver Design Requirements in Volume 1 of the WPC v1.2 specification highlights in detail the
sizing requirements. To summarize, the receiver designer will be required to take inductance measurements with
a standard test fixture as shown in Figure 10-3:
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
31
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
Magnetic
Attractor
(example)
Interface
Surface
Secondary Coil
Shielding (optional)
Mobile
Device
Spacer
dz
Primary Shielding
Figure 10-3. WPC V1.2 Receiver Coil Test Fixture For the Inductance Measurement Ls’ (Copied From
System Description Wireless Power Transfer, Volume 1: Low Power, Part 1 Interface Definition, Version
1.1)
The primary shield is to be 50 mm × 50 mm × 1 mm of Ferrite material PC44 from TDK Corp. The gap dZ is to
be 3.4 mm. The receiver coil, as it will be placed in the final system (for example, the back cover and battery
must be included if the system calls for this), is to be placed on top of this surface and the inductance is to be
measured at 1-V RMS and a frequency of 100 kHz. This measurement is termed Ls’. The same measurement
is to be repeated without the test fixture shown in Figure 10-3. This measurement is termed Ls or the free-space
inductance. Each capacitor can then be calculated using Equation 6:
2
é
ù
C1 = ê fS ´ 2p ´ L'S ú
ë
û
(
)
-1
é
2
1ù
C2 = ê fD ´ 2p ´ LS ú
C1 úû
êë
(
)
-1
(6)
where
•
•
fS is 100 kHz +5/-10%.
fD is 1 MHz ±10%.
C1 must be chosen first prior to calculating C2.
The quality factor must be greater than 77 and can be determined by Equation 7:
Q=
2p× f × LS
D
R
(7)
where
•
R is the DC resistance of the receiver coil.
All other constants are defined above.
For this application, the selected coil inductance, Ls, is 11 µH and the Ls' is 16 µH with a DC resistance of 191
mΩ. Using Equation 6, the C1 resolves to 158.3 nF (with a range of 144 nF to 175 nF). For an optimum solution
of 3 capacitors in parallel, the chosen capacitors are 68 nF, 47 nF, and 39 nF for a total of 154 nF, well within the
32
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
desired range. Using the same equation (and the chosen value for C1), C2 resolves to 2.3 nF. This is easily met
with capacitors of 2.2 nF and 100 pF. The C1 and C2 capacitors must have a minimum voltage rating of 25 V.
Solving for the quality factor (Q in Equation 7), gives a value of over 500.
Table 10-1 lists the recommended RX coils.
10.2.1.2.3 Recommended RX Coils
Table 10-1. Recommended RX Coils
MANUFACTURER
PART NUMBER
DIMENSIONS
Ls
Ls’
OUTPUT CURRENT
RANGE
APPLICATION
Mingstar
312-00015
28 mm × 14 mm
36.3 µH
43.7 µH(1)
50 mA - 1000 mA
General 5-V Power Supply
NuCurrent
NC-01R37L02O-25250R53
25 mm (round)
10.9 µH
14.1 µH(1)
50 mA - 1000 mA
General 5-V Power Supply
TDK
WR483265-15F5-G
48 mm × 32 mm
13.2 µH
18.8 µH(1)
50 mA - 1000 mA
General 5-V Power Supply
Vishay
IWAS-4832FF-50
48mm × 32 mm
10.9 µH
15.8 µH(2)
50 mA - 1000 mA
General 5-V Power Supply
(1)
(2)
Ls’ measurements conducted with a standard battery behind the RX coil assembly. This measurement is subject to change based on
different battery sizes, placements, and casing material.
Battery not present behind the RX coil assembly. Subject to drop in inductance depending on the placement of the battery.
TI recommends that all inductance measurements are repeated in the designers specific system as there are
many influence on the final measurements.
10.2.1.2.4 COMM, CLAMP, and BOOT Capacitors
For most applications, the COMM, CLAMP, and BOOT capacitance values will be chosen to match the
BQ51013BEVM-764.
The BOOT capacitors are used to allow the internal rectifier FETs to turn on and off properly. These capacitors
are from AC1 to BOOT1 and from AC2 to BOOT2 and must have a minimum 25-V rating. A 10-nF capacitor with
a 25-V rating is chosen.
The CLAMP capacitors are used to aid in the clamping process to protect against overvoltage. These capacitors
are from AC1 to CLAMP1 and from AC2 to CLAMP2 and must have a minimum 25-V rating. A 0.47-µF capacitor
with a 25-V rating is chosen.
The COMM capacitors are used to facilitate the communication from the RX to the TX. This selection can vary
a bit more than the BOOT and CLAMP capacitors. In general, a 22-nF capacitor is recommended. Based on the
results of testing of the communication robustness in the final solution, a change to a 47-nF capacitor may be in
order. The larger the capacitor the larger the deviation will be on the coil which sends a stronger signal to the TX.
This also decreases the efficiency somewhat. In this case, a 22-nF capacitor with a 25-V rating is chosen.
10.2.1.2.5 Control Pins and CHG
This section discusses the pins that control the functions of the BQ51013B-Q1 (AD, AD_EN, EN1, EN2, and
TS/CTRL).
This solution uses wireless power exclusively. The AD pin is tied low to disable wired power interaction. The
output pin AD_EN is left floating.
EN1 and EN2 are tied to the system controller GPIO pins. This allows the system to control the wireless power
transfer. Normal operation leaves EN1 and EN2 low or floating (GPIO low or high impedance). EN1 and EN2
have internal pulldown resistors. With both EN1 and EN2 low, wireless power is enabled and power can be
transferred whenever the RX is on a suitable TX. The RX system controller can terminate power transfer and
send an EPT 0x01 (Charge Complete) by setting EN1=EN2=1. The TX will terminate power when the EPT 0x01
is received. The TX will continue to test for power transfer, but will not engage until the RX requests power.
For example, if the TX is the BQ500212A, the TX will send digital pings approximately once per 5 seconds.
During each ping, the BQ51013B-Q1 will resend the EPT 0x01. Between the pings, the BQ500212A goes into
low power "Sleep" mode reducing power consumption. When the RX system controller determines it is time to
resume power transfer (for example, the battery voltage is below its recharge threshold) the controller simply
returns EN1 and EN2 to low (or float) states. The next ping of the BQ500212A will power the BQ51013B-Q1
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
33
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
which will now communicate that it is time to transfer power. The TX and RX communication resumes and power
transfer is reinitiated.
The TS/CTRL pin will be used as a temperature sensor (with the NTC) and maintain the ability to terminate
power transfer through the system controller. In this case, the GPIO will be in high impedance for normal NTC
(Temperature Sense) control.
The CHG pin is used to indicate power transfer. A 2.1-V forward bias LED is used for D1 with a current limiting
1.5-kΩ series resistor. The LED and resistor are tied from OUT to PGND and D1 will light during power transfer.
10.2.1.2.6 Current Limit and FOD
The current limit and foreign object detection functions are related. The current limit is set by R1 + RFOD. RFOD
and Ros are determined by FOD calibration. Default values of 20 kΩ for Ros and 196 Ω for RFOD are used. The
final values need to be determined based on the FOD calibration. The tool for FOD calibration can be found on
the BQ51013B-Q1 web folder under "Tools & software". Good practice is to set the layout with 2 resistors for Ros
and 2 for RFOD to allow for precise values once the calibration is complete.
After setting RFOD, R1 can be calculated based on the desired current limit. The maximum current for this
solution under normal operating conditions (IMAX) is 1 A. Using Equation 2 to calculate the maximum current
yields a value of 262 Ω for RILIM. With RFOD set to 196 Ω the remaining resistance for R1 is 66 Ω. This also sets
the hardware current limit to 1.2 A to allow for temporary current surges without system performance concerns.
10.2.1.2.7 RECT and OUT Capacitance
RECT capacitance is used to smooth the AC to DC conversion and to prevent minor current transients from
passing to OUT. For this 1-A IMAX, select two 10-µF capacitors and one 0.1-µF capacitor. These should be rated
to 16 V.
OUT capacitance is used to reduce any ripple from minor load transients. For this solution, a single 10-µF
capacitor and a single 0.1-µF capacitor are used.
10.2.1.3 Application Curves
Figure 10-4 shows wireless power start-up when the RX is placed on the TX. In this case, the BQ500212A is
used as the transmitter. When the rectifier voltage stabilizes, the output is enabled and current is passed. In
this case, the load is resistive generating 900 mA. The pulses on the RECT pin indicate communication packets
being transferred from the RX to the TX.
Figure 10-5 shows a current transition. The plot shows a 1-A load removed then added again. Note the stability
of VOUT.
IOUT
VOUT
VOUT
IOUT
VRECT
VRECT
Figure 10-4. Start-Up With 900-mA Load
34
Figure 10-5. Load Transitions (1 A to 0 A to 1 A)
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
10.2.2 Dual Power Path: Wireless Power and DC Input
System
Load
Q1
USB or
AC Adapter
Input
AD-EN
AD
OUT
CCOMM1
C4
COMM1
C5
CBOOT1
BOOT1
C1
AC1
C3
R4
BQ51013B-Q1
C2
COIL
D1
ROS
RECT
TS/CTRL
AC2
NTC
BOOT2
CBOOT2
HOST
COMM2
CHG
CCOMM2
CCLAMP2
CCLAMP1
Tri-State
CLAMP2
EN1
Bi-State
CLAMP1
EN2
Bi-State
ILIM
R1
FOD
PGND
RFOD
Figure 10-6. BQ51013B-Q1 Used as a Wireless Power Receiver and Power Supply for System Loads With
Adapter Power-Path Multiplexing
10.2.2.1 Design Requirements
This solution adds the ability to disable wireless charging with the AD and AD_EN pins. A DC supply (USB or
AC Adapter with DC output) can also be used to power the subsystem. This can occur during wireless power
transfer or without wireless power transfer. The system must allow power transfer without any back-flow or
damage to the circuitry.
10.2.2.2 Detailed Design Procedure
The components chosen for the Section 10.2.1 system are identical. Adding a blocking FET while using the
BQ51013B-Q1 for control is the only addition to the circuitry.The AD pin will be tied to the DC input as a
threshold detector. The AD_EN pin will be used to enable or disable the blocking FET. The blocking FET must be
chosen to handle the appropriate current level and the DC voltage level supplied from the input. In this example,
the expectation is that the DC input will be 5 V with a maximum current of 1 A (same configuration as the
wireless power supply). The CSD75207W15 is a good fit because it is a P-Channel, –20-V, 3.9-A FET pair in a
1.5-mm2 WCSP.
The following scope plots show behavior under different conditions.
Figure 10-7 shows the transition from wireless power to wired power when power is added to the AD pin. VRECT
drops and there is a short time (IOUT drops to zero) when neither source is providing power. When Q1 is enabled
(through AD_EN) the output current turns back on. Note the RECT voltage after about 500 ms. This is the TX
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
35
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
sending a ping to check to see if power is required. RECT returns to low after the BQ51013B-Q1 informs the TX
it does not need power (without enabling the OUT pin). This timing is based on the TX (BQ500212A used here).
Figure 10-8 shows the transition to wireless power when the AD voltage is removed. Note that after wired power
is removed, the next ping from the (BQ500212A) will energize the BQ51013B. Once the rectifier voltage is stable
the output will turn on.
Figure 10-9 shows a system placed onto the transmitter with AD already powered. The TX sends a ping which
the RX responds to and informs the TX that no power is needed. The ping will continue with the timing based on
the TX used.
Figure 10-10 shows the AD added when the RX is not on a TX. This indicates normal start-up without
requirement of the TX.
10.2.2.3 Application Curves
VOUT
VAD
IOUT
VOUT
IOUT
VRECT
VRECT
VAD
Figure 10-7. Transition Between Wireless Power
and Wired Power (EN1 = EN2 = LOW)
VAD
VAD
VOUT
VOUT
IOUT
IOUT
VRECT
VRECT
Figure 10-9. Wireless Power Start-Up With VAD = 5
V (EN1 = EN2 = LOW)
36
Figure 10-8. Transition Between Wired Power and
Wireless Power (EN1 = EN2 = LOW)
Figure 10-10. AD Power Start-Up With No
Transmitter (EN1 = EN2 = LOW)
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
10.2.3 Wireless and Direct Charging of a Li-Ion Battery at 800 mA
Q1
USB or
AC Adapter
Input
1.5 KŸ
BQ51013B-Q1
Output
1
AD-EN
BOOT1
CBOOT1
C3
AC2
COMM2
CCLAMP2
CCLAMP1
Ÿ
HOST
CLAMP2
EN1
CLAMP1
EN2
Bi-State
R1
PRETERM
5
/PG
/CHG
8
ISET2
7
NC
6
2 KŸ
CHG
Tri-State
Bi-State
ILIM
4
BQ24040
R4
NTC
BOOT2
VSS
9
PACK-
TS/CTRL
CBOOT2
3
TS
TEMP
BQ51013B-Q1
CCOMM2
ISET
SYSTEM
Load
PACK+
D1
ROS
RECT
AC1
C2
COIL
2
C4
COMM1
C1
1ÛF
1.5 KŸ
OUT
CCOMM1
C5
OUT 10
IN
1ÛF
AD
FOD
PGND
ISET/100/500mA
RFOD
Figure 10-11. BQ51013B-Q1 Used as a Wireless Power Supply With Adapter Multiplexing for a Linear
Charger
10.2.3.1 Design Requirements
The goal of this design is to charge a 3.7-V Li-Ion battery at 800 mA either wirelessly or with a direct USB
wired input. This design will use the BQ51013B-Q1 wireless power supply and the BQ24040 single-cell Li-Ion
battery charger. A low resistance path has to be created between the output of BQ51013B-Q1 and the input of
BQ24040.
10.2.3.2 Detailed Design Procedure
The basic BQ51013B-Q1 design is identical to the Section 10.2.2. The BQ51013B-Q1 OUT pin is tied to the
output of Q1 and directly to the IN pin of the BQ24040. No other changes to the BQ51013B-Q1 circuitry are
required.
The BQ24040 has a few parameters that need to be programmed for this charger to work properly. Ceramic
decoupling capacitors are needed on the IN and OUT pins using the values shown in Figure 10-11. After
evaluation during actual system operational conditions, the final values may be adjusted up or down. In high
amplitude pulsed load applications, the IN and OUT capacitors will generally require larger values. The next step
is setting up the fast charge current and pre-charge and termination current.
Program the Fast Charge Current, ISET: RISET = [KISET/IOUT] = [540 AΩ / 0.8 A] = 675 Ω.
Program the Termination Current, ITERM: RPRE-TERM = [KTERM/%OUT-FC] = 200 Ω/% x 10% = 2 kΩ.
TS Function: To enable the temperature sense function, a 10-kΩ NTC thermistor (103AT) from TS to VSS should
be placed in the battery pack. To disable the temperature sense function, use a fixed 10-kΩ resistor between TS
and VSS.
Figure 10-12 shows start-up of the wireless system with the BQ24040 charger when TX power is applied after
the full RX system has been placed on the charging pad. Channel 1 (yellow) shows the initial power to the TX
system. The RECT pin of the BQ51013B-Q1 is shown on Channel 3 (purple). The output of the BQ24040 is
shown on Channel 2 (blue). Battery current can be seen on Channel 4 (green).
Figure 10-13 shows a similar condition but in this case, the battery is not connected initially, so the battery
detection routine can be observed. After the battery is connected to the charger, the charge current jumps to 800
mA and the output voltage becomes stable. Both the current out of the BQ51013B-Q1 (Channel 1, yellow) and
the current out of the BQ24040 (Channel 4, green) can be seen.
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
37
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
10.2.3.3 Application Curves
The following plots show the performance of the BQ51013B-Q1 + charger solution.
Figure 10-12. System Start-Up (200 ms / division)
Figure 10-13. System Start-Up With Battery
Inserted After Wireless Power is Enabled (1 s /
division)
11 Power Supply Recommendations
The BQ51013B-Q1 requires a Qi-compatible transmitter as its power source.
12 Layout
12.1 Layout Guidelines
•
•
•
•
•
•
Keep the trace resistance as low as possible on AC1, AC2, and BAT.
Detection and resonant capacitors must be as close to the device as possible.
COMM, CLAMP, and BOOT capacitors must be placed as close to the device as possible.
Via interconnect on PGND net is critical for appropriate signal integrity and proper thermal performance.
High frequency bypass capacitors must be placed close to RECT and OUT pins.
ILIM and FOD resistors are important signal paths and the loops in those paths to PGND must be minimized.
Signal and sensing traces are the most sensitive to noise; the sensing signal amplitudes are usually
measured in mV, which is comparable to the noise amplitude. Make sure that these traces are not being
interfered by the noisy and power traces. AC1, AC2, BOOT1, BOOT2, COMM1, and COMM2 are the main
source of noise in the board. These traces should be shielded from other components in the board. It
is usually preferred to have a ground copper area placed underneath these traces to provide additional
shielding. Also, make sure they do not interfere with the signal and sensing traces. The PCB should have a
ground plane (return) connected directly to the return of all components through vias (two vias per capacitor
for power-stage capacitors, one via per capacitor for small-signal components).
For a 1-A fast charge current application, the current rating for each net is as follows:
–
–
–
–
–
–
AC1 = AC2 = 1.2 A
OUT = 1 A
RECT = 100 mA (RMS)
COMMx = 300 mA
CLAMPx = 500 mA
All others can be rated for 10 mA or less
For the RHL package, the thermal pad should be connected to ground to help dissipate heat.
38
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
12.2 Layout Example
For the RHL package, the thermal pad should be connected to ground to help dissipate heat.
Figure 12-1. BQ51013B-Q1 Layout Schematic
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
39
BQ51013B-Q1
www.ti.com
SLUSEE3 – JULY 2021
13 Device and Documentation Support
13.1 Device Support
13.1.1 Third-Party Products Disclaimer
TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT
CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES
OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER
ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.
13.1.2 Development Support
The tool for Foreign Object Detection (FOD) Calibration can be found on the BQ51013B-Q1 web folder under
Tools and software.
13.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
13.3 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
13.4 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
13.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
13.6 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
14 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
40
Submit Document Feedback
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: BQ51013B-Q1
PACKAGE OPTION ADDENDUM
www.ti.com
29-Jul-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
BQ51013BQWRHLRQ1
ACTIVE
VQFN
RHL
20
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
51013BQW
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
工商网监
湘ICP备2023018690号
