Sample &
Buy
Product
Folder
Support &
Community
Tools &
Software
Technical
Documents
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
TPS6123x 8-A Valley Current Synchronous Boost Converters with Constant Current
Output Feature
1 Features
3 Description
•
•
•
•
•
•
•
•
•
The TPS6123x is a high current, high efficiency
synchronous boost converter with constant output
current feature for single cell Li-Ion and Li-polymer
battery powered products, in a wide range of power
bank, tablet, and other portable devices. The IC
integrates 14-mΩ/14-mΩ power switches and is
capable of delivering up to a 3.5-A output current for
3.3-V to 5-V conversion with up to 97% high
efficiency. The device supports a programmable
constant output current to control power delivery, so
to save power path components and lower total
system thermal dissipation effectively.
1
•
•
•
Up to 97% Efficiency Synchronous Boost
Up to 3.5-A IOUT for 3.3-V to 5-V Conversion
10-A 14-mΩ/14-mΩ Internal Power Switches
Programmable Constant Output Current
Output Current Monitor
10-µA IQ under Light Load Condition
Boost Status Indication
True disconnection during shutdown
Fixed 5.1-V Output Voltage (TPS61235P) or
Adjustable Output Voltage from 2.9-V to-5.5 V
(TPS61236P)
1-MHz Switching Frequency
Softstart, Current Limit, Over Voltage and Over
Thermal Protections
2.5 mm x 2.5 mm VQFN Package
2 Applications
•
•
•
•
•
•
The device only consumes a 10-µA quiescent current
under a light load condition, and can report load
status to the system, which make it very suitable for
Always-On applications. With the TPS6123x, a simple
and flexible system design can be achieved,
eliminating external power path components, saving
PCB space, and reducing BOM cost.
In shutdown, the output is completely disconnected
from the input, and current consumption is reduced to
less than 1 µA. Other features like soft start control,
reverse current blocking, over voltage protection, and
thermal shutdown protection are built-in for system
safety.
Power Banks, Battery Backup Units
USB Charging Port
USB Type-C
Battery Powered USB Hub
Tablet PCs
Battery Powered Products
The devices are available in a 2.5-mm x 2.5-mm
VQFN package.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
TPS61235P
VQFN (9)
2.50 mm x 2.50 mm
TPS61236P
VQFN (9)
2.50 mm x 2.50 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
SPACING
TPS61235P Typical Application
5.1 V
VOUT
VIN
FB
VOUT
C1
10 PF
TPS61235P
ON
OFF
95
C2
22 PF x 3
EN
90
Efficiency (%)
SW
Li-Ion
Battery
Typical Application Efficiency (TPS61235P)
100
L1
1 PH
85
80
75
70
CC
INACT
2.7 V Input
3.3 V Input
3.6 V Input
4.2 V Input
65
60
0
AGND PGND
0.5
1
1.5
2
2.5
3
3.5
Output Current (A)
4
4.5
5
D001
Copyright © 2016, Texas Instruments Incorporated
1
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.
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
3
4
7.1
7.2
7.3
7.4
7.5
7.6
4
4
4
4
5
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Detailed Description .............................................. 9
8.1
8.2
8.3
8.4
Overview ................................................................... 9
Functional Block Diagram ......................................... 9
Feature Description................................................. 10
Device Functional Modes........................................ 15
9
Applications and Implementation ...................... 16
9.1 Application Information............................................ 16
9.2 Typical Applications ................................................ 16
10 Power Supply Recommendations ..................... 26
11 Layout................................................................... 27
11.1 Layout Guidelines ................................................. 27
11.2 Layout Example .................................................... 27
11.3 Thermal Considerations ........................................ 28
12 Device and Documentation Support ................. 29
12.1
12.2
12.3
12.4
12.5
12.6
12.7
12.8
Device Support......................................................
Documentation Support .......................................
Related Links ........................................................
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
29
29
29
29
29
29
29
30
13 Mechanical, Packaging, and Orderable
Information ........................................................... 30
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (September 2015) to Revision A
•
2
Page
Changed part numbers to TPS61235P and TPS61236P for Pb-free nomenclature ............................................................. 1
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
5 Device Comparison Table
PART NUMBER
OUTPUT VOLTAGE
TPS61235P
5.1 V
TPS61236P
Adjustable
6 Pin Configuration and Functions
RWL Package
9-Pin VQFN
Top View
2
VIN
3
CC
4
5
6
9
VOUT
8
INACT
7
EN
SW
FB
1
AGND
PGND
Pin Functions
PIN
I/O
DESCRIPTION
NAME
NUMBER
PGND
1
PWR
Power ground.
The switch pin of the boost converter. It is connected to the drain of the internal Power MOSFETs.
SW
2
PWR
VIN
3
I
IC power supply input.
CC
4
I
Constant output current programming pin. Connect a resistor to this pin to program the constant output
current. A capacitor should be connected in parallel to stabilize the control loop. Connect this pin to the
AGND pin to disable the constant output current function.
AGND
5
I/O
FB
6
I
Voltage feedback pin of adjustable version (TPS61236P). Must be connected to VOUT pin on fixed
output voltage version (TPS61235).
EN
7
I
Enable logic input. Logic high enables the device. Logic low disables the device and puts it in
shutdown mode. This pin must be terminated and cannot be left floating. An external pull down resistor
connected to this pin is recommended.
INACT
8
O
Load status indication. Open drain output. Can be left float or connected to AGND pin if not used.
VOUT
9
PWR
Analog ground.
Boost converter output.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
3
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
Voltage (2)
MIN
MAX
UNIT
VIN, EN, VOUT, CC, INACT, FB
–0.3
6
V
SW
–0.3
7
V
Operating junction temperature, TJ
–40
150
°C
Storage temperature, Tstg
–65
150
°C
(1)
(2)
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 my affect device reliability.
All voltages are with respect to network ground terminal.
7.2 ESD Ratings
VALUE
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
V(ESD)
(1)
(2)
Electrostatic discharge
(1)
UNIT
±4000
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±1500
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
7.3 Recommended Operating Conditions
MIN
VIN (1)
Supply voltage at VIN pin
Target output voltage (TPS61235P)
VOUT
NOM
2.3
MAX
VOUT – 0.6
5.1
UNIT
V
V
Target output voltage (TPS61236P)
2.9
L
Effective inductance
0.7
1
CI
Effective input capacitance (2)
4.7
10
CO
Effective output capacitance (2)
20
CRCC
Capacitor parallel with the RCC resistor connected at CC pin
10
nF
RINACT
INACT pin pull up resistance
1
MΩ
REN
EN pin pull down resistance
1
MΩ
TJ
Operating junction temperature
(1)
(2)
1
5.5
V
1.3
µH
µF
µF
–40
125
°C
The maximum input voltage should be 0.6-V lower than the output voltage in Constant Voltage operation for the TPS6123x to function
correctly.
Effective capacitance value. Ceramic capacitor’s derating effect under bias should be considered when selecting capacitors.
7.4 Thermal Information
TPS61235P
TPS61236P
THERMAL METRIC (1)
RWL (VQFN)
UNIT
9 PINS
RθJA
Junction-to-ambient thermal resistance
28.7
°C/W
RθJC(top)
Junction-to-case(top) thermal resistance
24.1
°C/W
RθJB
Junction-to-board thermal resistance
10.9
°C/W
ψJT
Junction-to-top characterization parameter
0.1
°C/W
ψJB
Junction-to-board characterization parameter
10.8
°C/W
RθJC(bottom)
Junction-to-case(bottom) thermal resistance
1.6
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
7.5 Electrical Characteristics
TJ = –40°C to 125°C and VIN = 3.6 V. Typical values are at TJ = 25°C, unless otherwise noted.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
POWER SUPPLY
VIN
VUVLO
IQ
ISD
Input voltage
2.3
Input under voltage lockout
Quiescent current into VIN
VOUT – 0.6
VIN rising
2.2
Hysteresis
125
Quiescent current into VOUT
IC enabled, No Load, No switching,
VOUT = 5.1 V
Shutdown current into VIN
IC disabled, TJ = –40°C to 85°C
Output voltage range
TPS61236P
2.9
PWM mode,
TPS61235P
5.0
2.3
V
V
mV
5
11
µA
5
30
µA
0.01
3
µA
5.5
V
5.2
V
OUTPUT
VOUT
VFB
Output voltage
PFM mode,
TPS61235
PWM mode,
TPS61236P
Feedback voltage
5.2
1.219
PFM mode,
TPS61236P
VOVP
Output over voltage protection
threshold
ILKG_FB
Leakage current into FB pin
ILKG_SW
Leakage current into SW pin
IC disabled, TJ = –40°C to 85°C,
VSW = 5.1 V
ILKG_VOUT
Leakage current into VOUT pin
5.1
1.244
V
1.269
1.256
5.60
5.80
V
V
5.93
V
4000
nA
120
nA
0.05
2
µA
IC disabled, TJ = –40°C to 85°C,
VOUT = 5.1 V
0.05
2
µA
Line regulation
IOUT = 2A, VIN = 2.7 V to 4.5 V,
VOUT = 5.1 V
0.06
%/V
Load regulation
IOUT = 0.5 A to 3 A, VIN = 3.6 V,
VOUT = 5.1 V
0.06
%/A
TPS61235P, VFB = 5.1 V
TPS61236P, VFB = 1.244 V
POWER STAGE
RDS(on)
fsw
High side MOSFET on resistance
VOUT = 5.1 V
14
30
mΩ
Low side MOSFET on resistance
VOUT = 5.1 V
14
30
mΩ
Switching frequency
VOUT = 5.1 V, PWM mode
1000
1250
kHz
Constant output current limit accuracy
ILIM
Switch valley current limit
–15%
15%
RCC = 61.9 kΩ,
TJ = 25°C
–10%
10%
RCC = 61.9 kΩ,
TJ = –20°C to 125°C
–15%
15%
TJ = –20°C to 100°C
6.5
8
9.5
A
0.05
0.25
0.8
A
VOUT = 0 V,
TJ = 0°C to 125°C
ILIM_pre
Precharge mode current limit
IINACT_th
Inactive threshold
tINACT_delay
Deglitch delay
TSD
Thermal shutdown threshold
750
RCC = 124 kΩ,
TJ = 25°C
VOUT = 2 V
1.3
VOUT = 3 V
1.7
A
VOUT = 5.1 V
50
mA
VOUT = 5.1 V
15
ms
140
°C
15
°C
TJ rising
Hysteresis
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
A
5
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
Electrical Characteristics (continued)
TJ = –40°C to 125°C and VIN = 3.6 V. Typical values are at TJ = 25°C, unless otherwise noted.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
LOGIC INTERFACE
VEN_H
EN Logic high input voltage
VEN_L
EN Logic low input voltage
ILKG_EN
EN pin input leakage current
EN pin connected to GND or VIN
VINACT
INACT pin output low level voltage
ISINK_INACT = 80 µA
6
Submit Documentation Feedback
1.0
V
0.01
0.4
V
0.3
µA
0.4
V
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
7.6 Typical Characteristics
100
100
95
95
90
90
Efficiency (%)
Efficiency (%)
VIN = 3.6 V, VOUT = 5.0 V, TJ = –40°C to 125 °C, unless otherwise noted.
85
80
75
70
85
80
75
70
2.7 V Input
3.3 V Input
3.6 V Input
65
2.7 V Input
3.3 V Input
3.6 V Input
4.2 V Input
65
60
60
0
0.5
1
1.5
2
2.5
3
3.5
Output Current (A)
4
4.5
5
0
0.5
1
D001
VOUT = 4.5 V (TPS61236P), CC pin connected to GND
1.5
2
2.5
3
3.5
Output Current (A)
4
4.5
5
D001
VOUT = 5.1 V (TPS61235P), CC pin connected to GND
Figure 1. Efficiency vs Output Current with Different Inputs
Figure 2. Efficiency vs Output Current with Different Inputs
20
100
95
18
Supply Current (PA)
Efficiency (%)
90
85
80
75
70
2.7 V Input
3.3 V Input
3.6 V Input
4.2 V Input
65
0.5
1
1.5
2
2.5
3
3.5
Output Current (A)
4
4.5
14
12
10
2.5
60
0
16
5
VOUT = 5.5 V (TPS61236P), CC pin connected to GND
4.5
5
D001
Figure 4. No Load Supply Current vs Input Voltage
3
25
DC Pre-Charge Current (A)
20
Supply Current (PA)
3.5
4
Input Voltage (V)
VOUT = 5.1 V (TPS61235P), No Load, TA = 25°C
Figure 3. Efficiency vs Output Current with Different Inputs
15
10
5
0
-40
3
D001
2.5
2
1.5
1
VIN = 2.7 V
VIN = 3.6 V
VIN = 4.5 V
0.5
0
-20
0
20
40
Ambient Temperature (qC)
60
0
80
1
D001
VOUT = 5.1 V (TPS61235P), VIN = 3.6 V, No Load
Figure 5. No Load Supply Current vs Ambient Temperature
2
3
Output Voltage (V)
4
5
D001
TA = 25°C
Figure 6. DC Pre-Charge Current vs Output Voltage
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
7
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
Typical Characteristics (continued)
VIN = 3.6 V, VOUT = 5.0 V, TJ = –40°C to 125 °C, unless otherwise noted.
2
5
Minimum Resistance at Startup (:)
DC Pre-Charge Current (A)
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
TA = 85qC
TA = 25qC
TA = -40qC
0.2
0
4
3
2
1
0
0
0.5
1
1.5
2
2.5
Output Voltage (V)
3
3.5
4
2
2.5
3
D001
3.6-V Input
3.5
4
Input Voltage (V)
4.5
5
D001
VOUT = 5.1 V (TPS61235P), CC pin connected to GND, TA = 25°C
Figure 7. DC Pre-Charge Current vs Output Voltage
Figure 8. Minimum Load Resistance at Startup
8.3
9
8.2
Limit Current (A)
Current Limit (A)
8.5
8.1
8
7.9
8
7.5
7.8
7.7
2.7
3
3.3
3.6
3.9
Input Voltage (V)
4.2
7
-40
4.5
-20
D001
TA = 25°C
3
2.15
2.5
2
1.5
1
RCC = 41.2 k:
RCC = 61.9 k:
RCC = 124 k:
3
3.3
D001
2.1
2.05
2
1.95
1.9
1.85
3.6
3.9
Input Voltage (V)
4.2
4.5
Figure 11. Constant Output Current vs Input Voltage
Submit Documentation Feedback
1.8
-20
0
D001
VOUT = 5.1 V (TPS61235P), TA = 25°C
8
80
Figure 10. Current Limit vs Ambient Temperature
2.2
Constant Output Current (A)
Constant Output Current (A)
Figure 9. Current Limit vs Input Voltage
0
2.7
60
VIN = 3.6 V
3.5
0.5
0
20
40
Ambient Temperature (qC)
20
40
60
Ambient Temperature (qC)
80
100
D001
VOUT = 5.1 V (TPS61235P), RCC = 61.9 kΩ (CC current set to 2 A)
Figure 12. Constant Output Current vs Ambient
Temperature
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
8 Detailed Description
8.1 Overview
The TPS6123x is a high current, high efficiency synchronous boost converter with constant current output
feature. It is optimized for single cell Li-Ion and Li-polymer battery powered products, in a wide range of power
bank, tablet, and other portable devices. The converter integrates 14-mΩ /14-mΩ power switches and is capable
of delivering more than 3.5-A output current for 3.3-V to 5-V conversion. The low Rds(on) of the internal power
switches enables up to 97% power conversion efficiency.
The TPS6123x has two regulation loops, one is the output voltage regulation loop as the normal boost converters
have, and the other is the output current regulation loop. An external resistor can be used to program the
maximum output current, and once the output current reaches the programmed value, the current loop kicks in to
regulate the output current. The TPS6123x can also indicate the load status. These features can simplify system
design, eliminate external power path components like a load switch, and achieve much lower system thermal
dissipation and improve the total power conversion effectively.
The TPS6123x also consumes only 10-µA quiescent current under a light load condition. This low quiescent
current together with the load status indication function makes the device very suitable for Always-On
applications. For example, for a power bank application, the TPS6123x can remain always on and report load
status to the system controller.
8.2 Functional Block Diagram
VIN
SW
3
2
VIN
VOUT
9
VOUT
4
CC
6
FB
8
INACT
UVLO
Thermal
Shutdown
EN
VIN
Gate Driver
7
Logic
Current Sense
and IOUT
Monitor
Bootstrap
REF
TPS61236P
Soft Start
Control
1)
Pulse Modulator
TPS61235P
OVP & Short
Circuit Protection
VOUT
IINACT_th
IOUT
1
5
PGND
AGND
Copyright © 2016, Texas Instruments Incorporated
(1)
Internal FB resistor divider is implemented in TPS61235P only.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
9
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
8.3 Feature Description
8.3.1 Boost Controller Operation
The TPS6123x synchronous boost converter typically operates at a quasi-constant 1-MHz frequency Pulse Width
Modulation (PWM) at moderate to heavy load, which allows the use of small inductors and capacitors to achieve
a small solution size. At light load, it operates in power-save mode with Pulse Frequency Modulation (PFM) for
improved efficiency.
During PWM operation, the converter uses a quasi-constant on-time valley current mode control scheme to
achieve excellent line/load regulation. Based on the VIN /VOUT ratio, a simple circuit predicts the required on-time.
At the beginning of the switching cycle, the low-side NMOS switch is turned on and the inductor current ramps up
to a peak current that is determined by the on-time and the inductance. Once the on-time has expired, the lowside switch is turned off and the rectifying NMOS switch is turned on. The inductor current decays until reaching
the valley current threshold which is determined by internal control loops. Once this occurs, the on-time is set
again to turn the low-side switch back on and the cycle is repeated. Internal loop compensation is implemented
to simplify the design process while minimizing the number of external components. A bootstrap circuit is built in
to drive the rectifying NMOS switch. Figure 13 illustrates the PWM mode operation.
IPEAK
Inductor
Current
¨,L
IVALLEY
(loop controlled)
ton
fsw
Figure 13. PWM Mode Operation Illustration
Under a light load condition, the converter works in Pulse Frequency Modulation (PFM) mode. In this mode, the
boost converter switches and ramps up the output voltage until VOUT reaches the PFM threshold. Then it stops
switching and consumes less quiescent current. It resumes switching when the output voltage drops below the
threshold. The converter exits PFM mode when the output current can no longer be supported in this mode.
Refer to Figure 14 for PFM mode operation details.
Output Voltage
PFM mode at light load
VOUT_PFM
one PFM cycle
VOUT_NOM
PWM mode at heavy load
t
Figure 14. PFM Mode Operation Illustration
8.3.2 Soft Start
The TPS6123x integrates an internal soft start circuit which controls ramp up of the output voltage and prevents
the converter from inrush current during start-up.
When the device is enabled, the rectifying switch is turned on to charge the output capacitor to the input voltage.
This is called the pre-charge phase. During the phase, the output current is limited to the pre-charge current limit
ILIM_pre, which is proportional to the output voltage. The pre-charge current increases when the output voltage
gets higher.
10
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
Feature Description (continued)
Once the output capacitor is charged close to the input voltage, the converter starts switching. This is called the
start-up switching phase. During the phase, the converter steps up the voltage to its nominal output voltage by
following an internal ramp up reference voltage, which ramps up in around 3 ms (typ.) to its final value. The
current limit function is activated in this phase.
Because of the current limitation during the pre-charge phase, the TPS6123x may not be able to start up under a
heavy load condition. It is recommended to apply no load or a light load during the startup process, and apply the
full load only after the TPS6123x starts up successfully. Refer to Figure 8 for the recommended minimum load
resistance.
8.3.3 Enable and Disable
An external logic signal at the EN pin can enable and disable the device.
The TPS6123x device starts operation when EN is set high and starts up with the soft-start process. For proper
operation, the EN pin must be terminated and must not be left floating. Pulling EN low forces the device into
shutdown, with a shutdown current of typically 0.01 µA. In shutdown mode, a true disconnection between input
and output is implemented. It can prevent current from input to output, or reverse current from output to input.
8.3.4 Constant Output Voltage and Constant Output Current Operations
Normally a boost converter only regulates its output voltage, but for the TPS6123x, it is different. There are two
regulation loops for the device. One loop regulates the output voltage, and it is called CV (Constant Voltage)
operation; the other regulates the output current, and it is called CC (Constant Current) operation.
8.3.4.1 Constant Voltage Operation
Before the output current reaches the constant current value programmed by an external resistor at the CC pin,
the voltage regulation loop dominates. The output voltage is monitored via external or internal feedback network
resistors at the FB pin. An error amplifier compares the feedback voltage to an internal reference voltage VREF
and adjusts the inductor current valley accordingly. In this way, the TPS6123x operates as a normal boost
converter to regulate the output voltage.
During CV operation, the maximum VIN should be 0.6-V below VOUT to keep the output voltage well regulated.
The TPS6123x may enter into pass-through operation prematurely when VIN is close to but still below VOUT, and
exists when VIN is below the threshold with a hysteresis. When in pass-through operation, the boost converter
stops switching and keeps the rectifying switch on, so the input voltage can pass through the external inductor
and internal rectifying switch to the output. The output current capability becomes lower and is limited by the precharge current limit ILIM_pre of the rectifying switch. More than 0.4-V under-voltage of VOUT may occur due to the
premature pass-through operation and the hysteresis of existing. If the under-voltage is not acceptable, the
maximum VIN should be limited to 0.6-V below VOUT , which gives enough margin to avoid the pass-through
operation.
8.3.4.2 Output Current Monitor
During the CV operation, the output current can be monitored at the CC pin. In the TPS6123x, the inductor
current is sensed through the rectifying switch during the off-time of each switching cycle. The device then builds
a current signal which is 1/K times the sensed current and feeds it to the CC pin during off-time. As a result, the
CC pin voltage, VCC, is proportional to the average output current as Equation 1 shows.
IOUT
VCC
˜ R CC
(1)
K
Where:
VCC is the voltage at the CC pin,
IOUT is the output current,
K is the coefficient between the output current and the internal built current signal, K = 100,000,
RCC is the resistor connected at the CC pin.
A capacitor must be connected in parallel with RCC to average the CC pin voltage and also stabilize the control
loop. Normally a 10-nF capacitor is recommended. A larger capacitor at the CC pin will smooth the CC voltage
better, and also slow down the loop response.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
11
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
Feature Description (continued)
The CC pin can be connected to ground to disable the output current monitor function, and it will not affect the
CV operation.
8.3.4.3 Constant Current Operation
As Equation 1 shows, the CC pin voltage is proportional to the output current. The TPS6123x monitors the CC
pin voltage and compares it to an internal reference voltage VREF, which is 1.244 V typically. When VCC exceeds
VREF, the CC regulation loop kicks in and pulls the inductor current valley to a lower value so to keep the CC pin
voltage at VREF. Equally, the output current is regulated at the set value as Equation 2.
VREF
IOUT _ CC
˜K
R CC
(2)
Where:
IOUT_CC is the set constant output current,
VREF is the internal reference voltage, 1.244 V typically,
RCC is the resistor connected at the CC pin,
K is the coefficient between the output current and the internal built current signal, K = 100,000.
If the load current is higher than the CC setting, the output voltage drops. A balance can be achieved if the load
decreases and matches the CC current before VOUT is pulled below input voltage. In the balance status, the
TPS6123x can keep CC operation, output the constant current, and maintain the output voltage at the balanced
level. If the output voltage is pulled below the input voltage by a strong load before the balance is achieved, the
device exits CC operation and enters into start-up process, where the output current is limited by ILIM_pre instead
of the CC value. If the load is still higher than ILIM_pre, the device will be stuck in the pre-charge phase; otherwise,
the device can complete the pre-charge phase, but its output voltage will be pulled down again in the switching
phase due to the limited output current, so an oscillation may happen.
In order to avoid the potential oscillation, the CC operation is only recommended for pure resistive loads or load
devices with dynamic power management function. For a resistive load, its resistance should be higher than VIN /
IOUT_CC; for a load device with dynamic power management function, which can regulate its input voltage to a set
value, a higher set voltage than VIN of the TPS6123x is suggested. By doing this, a balance can be achieved
before the output voltage is pulled below the input voltage, so to avoid the TPS6123x entering into the startup
process.
For effective CC operation, a capacitor must be connected in parallel with RCC at CC pin, and the CC value
should be set lower than the maximum output capability of the converter; otherwise, the TPS6123x will trigger the
over current protection first and fail to regulate the output current. Refer to the Over Current Protection section
for details.
The CC operation can be disabled by shorting the CC pin to ground. By doing so, the CC loop is disabled, so the
TPS6123x works as a normal boost converter to regulate the output voltage, and its maximum output current
capability is decided by the internal current limit.
8.3.5 Over Current Protection
To protect the device from over load condition, an internal cycle-by-cycle current limit is implemented. Once the
inductor valley current reaches the internal current limit, the protection is triggered and it clamps the valley
current at the limit ILIM until next cycle comes.
Figure 15 illustrates the valley current limit scheme. The average of the rectifier ripple current equals the output
current, IOUT(DC). When the load current increases, the loop increases the valley current accordingly. If the valley
current is increased above ILIM, the off-time will be extended until the valley drops to ILIM. Then the next cycle
begins.
12
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
Feature Description (continued)
Current Limit
Threshold
Rectifier
Current
¨,L
IPEAK
IVALLEY = ILIM
IOUT_MAX
¨,L
IOUT(DC)
Increased
Load Current
IIN(DC)
fSW
Inductor
Current
¨,L
IIN(DC)
Figure 15. Current Limit Operation
The maximum output current, IOUT_MAX, before the device enters into over current protection is decided by its
operation condition and the switch current limit threshold. It can be calculated by using the following equations.
'IL
IOUT _ MAX (1 D) ˜ (ILIM
)
2
(3)
VIN ˜ D
'IL
L ˜ fsw
(4)
D
1
VIN ˜ K
VOUT
(5)
Where:
D is the duty cycle of the boost converter,
ILIM is the switch valley current limit threshold,
ΔIL is the inductor current ripple,
L is the inductor value,
fSW is the switching frequency,
η is the conversion efficiency under the operation condition.
To estimate the maximum output current capability in the worst case, the minimum input voltage value, highest
fSW value, and minimum ILIM value should be used for the calculation. And η should be the efficiency under this
minimum VIN operation condition.
When the current limit is reached, the output voltage decreases during further load increases. If the output
voltage drops below the input voltage, the device enters into the start-up process.
8.3.6 Load Status Indication
The TPS6123x can indicate load status by the INACT pin. The INACT pin is an open drain output and should be
connected to a pull-up resistor. The INACT pin outputs high impedance when the boost converter works under
inactive status (no load or light load status), and it outputs low logic when the boost converter works under active
status (moderate load or heavy load status).
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
13
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
Feature Description (continued)
Load status is defined by operation mode and output current. When the converter works in PFM mode with IOUT
lower than the threshold IINACT_th for 16 PFM cycles, the boost enters inactive status. One PFM cycle is defined
from the time the boost starts switching to ramp up the output voltage to the time it resumes switching after the
output voltage drops below the PFM threshold, as shown in Figure 14. Once the output current is detected higher
than IINACT_th or the converter exits PFM mode, the boost enters active status. There is 10-ms typical deglitch
time when the INACT pin changes its output.
This indication function can report load status to a system controller, like an MCU. For example, it can be used to
realize the load insert detection in a power bank application, where the TPS6123x can be kept always on while
consuming only 10-µA quiescent current. When a load is applied, the TPS6123x detects the load and pulls the
INACT pin low to wake up the MCU. It eliminates the need for external load detection circuitry and simplifies the
system design.
8.3.7 Under voltage Lockout
Under voltage lockout prevents operation of the device at input voltages below typical 2.1-V. When the input
voltage is below the under voltage threshold, the device is shut down and the internal switch FETs are turned off.
If the input voltage rises by under voltage lockout hysteresis, the IC restarts.
8.3.8 Over Voltage Protection and Reverse Current Block
When the device detects the output voltage above the threshold VOVP, the over voltage protection will be
triggered. The device stops switching and turn off the low side switch and rectifying switch. The voltage at output
is blocked to input, and there is no reverse current. When the output voltage falls below the OVP threshold, the
device resumes normal operation.
8.3.9 Short Circuit Protection
If the output voltage is detected lower than the input voltage during operation, the TPS6123x will enter into the
pre-charge phase of the startup process. The output current is limited to ILIM_pre by the rectifying switch, which is
0.25-A typical when VOUT is short to ground. When the short circuit event is removed, the TPS6123x will start up
automatically.
Short circuit protection is only valid when the input voltage is below 4.5 V. If the input voltage is higher than 4.5
V, a long term short to ground event may damage the device.
8.3.10 Thermal Shutdown
The TPS6123x has a built-in temperature sensor which monitors the internal junction temperature, TJ. If the
junction temperature exceeds the threshold (140°C typical), the device goes into thermal shutdown, and the highside and low-side MOSFETs are turned off. When the junction temperature falls below the thermal shutdown
minus its hysteresis (15°C typical), the device resumes operation.
14
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
8.4 Device Functional Modes
8.4.1 PWM Mode
The TPS6123x boost converter operates at a quasi-constant 1-MHz frequency PWM mode at moderate to heavy
load currents. Refer to the Boost Controller Operation section for details.
8.4.2 PFM Mode
The TPS6123x works in PFM mode under light load conditions to improve light load efficiency. Refer to the Boost
Controller Operation section for details.
8.4.3 CV Mode and CC Mode
A resistor at the CC pin can program the maximum output current of the TPS6123x. Before the output current
reaches the programmed value, the TPS6123x works in CV (Constant Voltage) mode as a normal boost
converter. When the output current reaches the programmed value, the TPS6123x works in CC (Constant
Current) mode. Refer to the Constant Output Voltage and Constant Output Current Operations section for
details.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
15
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
9 Applications 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. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The TPS6123x family is designed to operate from an input voltage supply range from 2.3-V to (VOUT – 0.6)-V,
and the maximum output voltage can be up to 5.5-V. The device operates in PWM mode under medium to heavy
load conditions and in power save mode under light load condition. In PWM mode, the TPS6123x converter
operates with 1-MHz switching frequency which provides a controlled frequency variation over the input voltage
range. As load current decreases, the converter enters PFM mode, reducing switching frequency and minimizing
IC quiescent current to achieve high efficiency over the entire load current range. The TPS6123x also supports a
constant current output feature to limit the maximum output current at a programmed value.
9.2 Typical Applications
9.2.1 TPS61236P 3-V to 4.35-V Input, 5-V Output Voltage, 3-A Maximum Output Current
This example illustrates how to use the TPS61236P to generate a 5-V output voltage from a Li-ion battery input
and how to use the CC function to limit maximum output current to 3-A for the entire input voltage range.
L1
1 PH
Up to 3.0 A at 5 V
SW
Li-Ion
Battery
VOUT
VOUT
R1
1MŸ
VIN
C4
1 PF
C1
10 PF
FB
C2
22 PF x 3
R2
332kŸ
TPS61236P
ON
EN
OFF
R5
1MŸ
VDD
R4
1MŸ
CC
C3
10 nF
R3
41.2kŸ
INACT
AGND PGND
Copyright © 2016, Texas Instruments Incorporated
Figure 16. TPS61236P 5-V Output with 3-A Constant Output Current
9.2.1.1 Design Requirements
The design parameters for the TPS61236P 5-V 3-A constant output current design are listed in Table 1.
Table 1. TPS61236P 5-V 3-A Constant Output Current Design Parameters
16
DESIGN PARAMETERS
EXAMPLE VALUES
Input voltage range
3 V to 4.35 V
Output voltage
5V
Output current limit
3A
Operating frequency
1 MHz
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
9.2.1.2 Detailed Design Procedure
The following sections describe the selection process of the external components. The following table summaries
the final component selections.
Table 2. List of Components for TPS61236P 5-V Output with 3-A Constant Output Current Application
REFERENCE
(1)
DESCRIPTION
MANUFACTURER (1)
L1
1.0 μH, Power Inductor, XAL7030
Coilcraft
C1
10 μF 6.3 V, 0603, X5R ceramic, GRM188R60J106ME84
Murata
C2
3 × 22 μF 10 V, 0805, X5R ceramic, GRM21BR61A226ME44
Murata
C3
10 nF, 50 V, 0603, X5R ceramic, GRM188R61H103KA01D
Murata
C4
1 µF, 6.3 V, 0402, X5R ceramic, GRM152R60J105ME15
Murata
R1
1 MΩ, Resistor, Chip, 1/10W, 1%
Rohm
R2
332 kΩ, Resistor, Chip, 1/10W, 0.5%
Rohm
R3
41.2 kΩ, Resistor, Chip, 1/10W, 0.5%
Rohm
R4
1 MΩ, Resistor, Chip, 1/10W, 1%
Rohm
R5
1 MΩ, Resistor, Chip, 1/10W, 1%
Rohm
See Third-party Products Disclaimer
9.2.1.2.1 Programming the Output Voltage
The TPS61236P's output voltage needs to be programmed via an external voltage divider at the FB pin, as
shown in Figure 16.
By selecting R1 and R2, the output voltage is programmed to the desired value. When the output voltage is
regulated, the typical voltage at the FB pin is VFB. The following equation can be used to calculate R1 and R2.
R1
R1
VOUT VFB u (1
) 1.244 V u (1
)
R2
R2
(6)
For the best accuracy, the current following through R2 should be 100 times larger than FB pin leakage current.
Changing R2 towards a lower value increases the robustness against noise injection. Changing R2 towards
higher values reduces the FB divider current for achieving the highest efficiency at low load currents.
For the fixed output voltage version, TPS61235P, the FB pin must be tied to the output directly.
In this example, 1-MΩ and 332-kΩ resistors are selected for R1 and R2. High accuracy like 0.5% resistors are
recommended for better output voltage accuracy.
9.2.1.2.2 Program the Constant Output Current
The TPS6123x's constant output current can be programmed via an external resistor RCC at the CC pin.
Because the TPS6123x has an internal current limit function to protect the IC from over load situations, a user
should make sure the constant output current is set within the device's maximum load capability. If the constant
current is set too high, the output current will be limited by internal protection circuitry and cannot reach the set
value.
The maximum output capability is determined by the input to output voltage ratio and the internal current limit
ILIM. Refer to Equation 3, Equation 4, and Equation 5 for the maximum output current calculation. The minimum
input voltage, minimum current limit value, and maximum switching frequency value shall be used for the worst
case calculation.
In this example, the minimum input voltage is 3-V and output voltage is 5-V. The efficiency η can be estimated as
85% for the worst case condition. By checking the specification table, the minimum ILIM value is 6.5-A, and
maximum switching frequency fSW is 1250-kHz, so the calculation result of the maximum output current under the
worse case condition is 3.6-A.
After calculation, the 3-A constant current target is within the maximum output current range, so the user can set
it. Equation 2 can be used to select RCC (R3 in Figure 16). In this example, the calculation result of R3 is 41.47kΩ. A 1% accuracy 41.2-kΩ resistor is selected. By using it, the constant output current can be regulated at 3-A
typically.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
17
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
C3 must be connected in parallel with R3 to average the CC pin voltage and also stabilize the control loop. A
larger capacitor can smooth the CC voltage better, and also slow down the loop response. Normally a 10-nF
capacitor is recommended.
If the Constant Current function is not needed, the user can simply connect the CC pin to ground to disable it.
Under this configuration, the TPS6123x works as a normal boost converter, and its maximum output current is
decided by the internal current limit circuitry.
9.2.1.2.3 Inductor and Capacitor Selection
A boost converter requires two main passive components for storing energy during the conversion, an inductor
and an output capacitor. Please refer to the following sections to select the inductor and capacitor. Also refer to
the Recommended Operating Conditions for operation recommendations.
9.2.1.2.3.1 Inductor Selection
Because a 1-µH inductor normally has a higher current rating and smaller form factor than inductors of higher
values, the TPS6123x is optimized for 1-µH inductor operation. Inductors of other values may cause control loop
instability and so are not recommended.
It is advisable to select an inductor with a saturation current ISAT higher than the possible peak current flowing
through the inductor. The inductor's current rating IRMS should be higher than the average input current. The
inductor peak current varies as a function of the load, the input and output voltages, and can be estimated by
using Equation 7.
VIN ˜ D
'IL IOUT
IL _ peak IIN _ avg
2
1 D 2 ˜ L ˜ fsw
(7)
Where:
D is the duty cycle, and can be calculated by using Equation 5.
When estimating inductor peak current and average input current, the minimum input voltage, maximum output
current, and minimum switching frequency in the application should be used for the worst case calculation. In this
example, the minimum VIN is 3.0-V, maximum IOUT is 3-A, and minimum fsw is 750-kHz, so the inductor peak
current result is 6.9-A, and the average input current is 5.9-A with an 85% efficiency estimation.
Selecting an inductor with insufficient saturation current can lead to excessive peak current in the converter. This
could eventually harm the device and reduce reliability. To leave enough margin, it is recommended to choose
saturation current 20% to 30% higher than IL_PEAK.
The following inductors are recommended to be used in designs if the current rating allows.
Table 3. List of Inductors
INDUCTANCE [µH]
(1)
PART NUMBER
MANUFACTURER (1)
4.55
XAL7030-102ME
Coilcraft
7.1
SPM6530T-1R0M120
TDK
11
9
FDSD0630-H-1R0M
TOKO
6
23
SPM5020T-1R0M
TDK
ISAT [A]
IRMS [A]
DC RESISTANCE [mΩ]
1
28
21.8
1
14.1
13
1
19
1
11
See Third-party Products Disclaimer
9.2.1.2.3.2 Output Capacitor Selection
For the output capacitor, it is recommended to use small X5R or X7R ceramic capacitors placed as close as
possible to the VOUT and PGND pins of the IC. If, for any reason, the application requires the use of large
capacitors which cannot be placed close to the IC, using a smaller ceramic capacitor of 1-µF or 0.1-µF in parallel
to the large one is highly recommended. This small capacitor should be placed as close as possible to the VOUT
and PGND pins of the IC.
The TPS6123x requires at least 20-µF effective capacitance at output for stability consideration. Care must be
taken when evaluating a capacitor’s derating under bias. The bias can significantly reduce the effective
capacitance. Ceramic capacitors can have losses of as much as 50% of their capacitance at rated voltage.
Therefore, leave margin on the voltage rating to ensure adequate effective capacitance. In this example, three
22-µF capacitors of 10-V rating are used.
18
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
The ESR impact on the output ripple must be considered as well if tantalum or electrolytic capacitors are used.
Assuming there is enough capacitance such that the ripple due to the capacitance can be ignored, the ESR
needed to limit the VRipple is:
VRipple(ESR ) = IL(PEAK ) ´ ESR
(8)
9.2.1.2.3.3 Input Capacitor Selection
Multilayer X5R or X7R ceramic capacitors are an excellent choice for input decoupling of the step-up converter
as they have extremely low ESR and are available in small footprints. Input capacitors should be located as
close as possible to the device. The required minimum effective capacitance at input for the TPS6123x is 4.7-µF.
Considering the capacitor’s derating under bias, a 10-µF input capacitor is recommended, and a 22-μF input
capacitor should be sufficient for most applications. There is no limitation to use larger capacitors. It is
recommended to put the input capacitor close to the VIN and PGND pins of the IC. If, for any reason, the input
capacitor cannot be placed close to the IC, putting a small ceramic capacitor of 1-µF or 0.1-µF close to the IC's
VIN pin and ground pin is recommended.
Take care when a ceramic capacitor is used at the input and the power is being supplied through long wires,
such as from a wall adapter. A load step at the output may cause ringing at the VIN pin due to the inductance of
the long wires. This ringing can couple to the output and be mistaken as loop instability or could even damage
the part. Additional bulk capacitance (electrolytic or tantalum) should in this circumstance be placed between CIN
and the power source to reduce ringing.
9.2.1.2.4 Loop Stability, Feed Forward Capacitor
One approach of stability evaluation is to look from a steady-state perspective at the following signals:
• Switching node, SW
• Inductor current, IL
• Output ripple, VRipple(OUT)
When the switching waveform shows large duty cycle jitter or the output voltage or inductor current shows
oscillations, the regulation loop may be unstable. This is often a result of board layout and/or L-C combination.
Load transient response is another approach to check loop stability. During the load transient recovery time, VOUT
can be monitored for settling time, overshoot, or ringing that helps judge the converter’s stability. Without any
ringing, the loop has usually more than 45° of phase margin.
To improve output voltage undershoot and overshoot performance during heavy load transient such as a 2-A
load step transient, a feed forward capacitor Cff in parallel with R1 is recommended, as shown in Figure 17. The
feed forward capacitor increases the loop bandwidth by adding a zero, so to achieve smaller output voltage
undershoot, as shown in Figure 25. A 10-pF capacitor is suitable for most applications of the TPS6123x. See
Application Note SLVA289 for more application notes of feed forward capacitor.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
19
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
L1
1 PH
Up to 3.0 A at 5 V
SW
Li-Ion
Battery
VOUT
VOUT
R1
1MŸ
VIN
C1
10 PF
C4
1 PF
C5
10 pF
FB
C2
22 PF x 3
R2
332kŸ
TPS61236P
ON
EN
OFF
R5
1MŸ
VDD
R4
1MŸ
CC
C3
10 nF
R3
41.2kŸ
INACT
AGND PGND
Copyright © 2016, Texas Instruments Incorporated
Figure 17. TPS61236P with Cff
9.2.1.2.5 INACT Pin Pull-up Resistor
The INACT pin can be used to report boost converter loading status to the MCU. It is an open drain output and
should be connected with a pull up resistor. Normally a 1-MΩ resistor is recommended for the pull up resistor.
20
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
9.2.1.3 TPS61236P 5-V Output Application Curves
SW 3 V/div
SW 3 V/div
Inductor Current 1 A/div
VOUT(AC) 50 mV/div
VOUT(AC) 50 mV/div
Inductor Current 500 mA/div
VIN = 3.6 V, VOUT = 5 V, IOUT = 3.1 A
VIN = 3.6 V, VOUT = 5 V, IOUT = 100 mA
Figure 18. Switching Waveforms in PWM Mode
Figure 19. Switching Waveforms in PFM Mode
SW 3 V/div
EN 1 V/div
VOUT 2 V/div
VOUT(AC) 50 mV/div
INACT 3 V/div
Inductor
Current
1 A/div
Inductor Current 500 mA/div
VIN = 3.6 V, VOUT = 5 V, IOUT = 0 mA
VIN = 3.6 V, VOUT = 5 V, RL = 2.5 Ω
Figure 20. Switching Waveforms in PFM Mode
EN 1 V/div
Figure 21. Startup
VOUT (5 V DC Offset) 500 mV/div
VOUT 2 V/div
IOUT 1 A/div
INACT 3 V/div
Inductor
Current
1 A/div
Inductor
Current
1 A/div
VIN = 3.6 V, VOUT = 5 V, RL = 2.5 Ω
VIN = 3.6 V, VOUT = 5 V, IOUT = 500 mA to 2 A
Figure 22. Shutdown Waveforms
Figure 23. Load Transient Response
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
21
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
VOUT (5 V DC Offset) 200 mV/div
VIN (2.8 V DC Offset) 500 mV/div
Inductor
Current
1 A/div
Inductor Current 1 A/div
IOUT 1 A/div
VOUT (5 V DC Offset) 100 mV/div
VIN = 2.8 V to 3.3 V, VOUT = 5 V, IOUT = 2 A
VIN = 3.6 V, VOUT = 5 V, IOUT = 500 mA to 2 A, Cff = 10 pF
Figure 25. Load Transient Response with Cff
Figure 24. Line Transient Response
VOUT (5 V DC Offset) 500 mV/div
VOUT (5 V DC Offset) 50 mV/div
VCC 500 mV/div
Inductor Current 1 A/div
IOUT 1 A/div
VIN (2.8 V DC Offset) 500 mV/div
Inductor Current 2 A/div
VIN = 2.8 V to 3.3 V, VOUT = 5 V, IOUT = 2 A, Cff = 10 pF
VIN = 3.6 V, VOUT = 5.1 V, RCC = 41.2 kΩ, RL = 2.5 Ω to 1.5 Ω
Figure 27. Constant Current Response
Figure 26. Line Transient Response with Cff
1.4
INACT 3 V/div
1.2
CC Pin Voltage (V)
VOUT
(5 V DC Offset)
100 mV/div
IOUT 2 A/div
Inductor Current 2 A/div
1
0.8
0.6
0.4
VIN = 4.2 V
VIN = 3.6 V
VIN = 3 V
0.2
VIN = 3.6 V, VOUT = 5 V, CC = 3.0 A, IOUT from 0 mA to 3 A
0
0
0.5
1
1.5
2
Output Current (A)
2.5
3
3.5
D001
RCC = 41.2 kΩ (CC current set to 3 A), TA = 25°C
Figure 28. Load Sweep
22
Submit Documentation Feedback
Figure 29. CC Pin Voltage vs Output Current with Different
Inputs
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
1.4
1.4
1.2
1.2
1
1
CC Pin Voltage (V)
CC Pin Voltage (V)
www.ti.com
0.8
0.6
0.4
TA = 85qC
TA = 25qC
TA = -40qC
0.2
0.8
0.6
0.4
VIN = 4.2 V
VIN = 3.6 V
VIN = 3 V
0.2
0
0
0
0.5
1
1.5
2
Output Current (A)
2.5
3
3.5
0
0.5
1
1.5
Output Current (A)
D001
RCC = 41.2 kΩ (CC current set to 3 A), VIN = 3.6 V
2
2.5
D001
RCC = 61.9 kΩ (CC current set to 2 A), TA = 25°C
Figure 30. CC Pin Voltage vs Output Current with Different
Ambient Temperatures
Figure 31. CC Pin Voltage vs Output Current with Different
Inputs
1.4
CC Pin Voltage (V)
1.2
1
0.8
0.6
0.4
TA = 85qC
TA = 25qC
TA = -40qC
0.2
0
0
0.5
1
1.5
Output Current (A)
2
2.5
D001
RCC = 61.9 kΩ (CC current set to 2 A), VIN = 3.6 V
Figure 32. CC Pin Voltage vs Output Current with Different Ambient Temperatures
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
23
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
9.2.2 TPS61236P 2.3-V to 5-V Input, 5-V 2-A Output Converter
In this application, the TPS6123x is required to be used as a standard boost converter to output 5-V voltage and
maximum 2-A current. The Constant Current function should be disabled, and the INACT function is not needed
either.
L1
1 PH
5V
SW
VOUT
VIN
C4
1 PF
C1
10 PF
VOUT
R1
1MŸ
Li-Ion Battery
FB
C2
22 PF x 3
R2
332kŸ
TPS61236P
ON
EN
OFF
R5
1MŸ
CC
INACT
AGND PGND
Copyright © 2016, Texas Instruments Incorporated
Figure 33. TPS61236P 5-V 2-A Output Typical Application
9.2.2.1 Design Requirements
The design parameters for the TPS61236P 5-V output current design are listed in Table 4.
Table 4. TPS61236P 5-V Output Design Parameters
DESIGN PARAMETERS
EXAMPLE VALUES
Input voltage range
2.3 V to 4.4 V
Output voltage
5V
Output current rating
2A
Operating frequency
1 MHz
9.2.2.2 Detailed Design Procedure
Refer to the Detailed Design Procedure section for the detailed design steps.
Because the CC function and the INACT function are not needed, the user can simply connect the two pins to
ground to disable the functions as shown in Figure 33.
24
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
4.8
5
4.7
4.5
Output Voltage (V)
Maximum Load Capacity After Startup (A)
9.2.2.3 TPS61236P 5-V Output Application Curves
4
3.5
3
TA = -40qC
TA = 25qC
TA = 85qC
2.5
2.5
4.6
4.5
4.4
4.3
2.7 V Input
3.3 V Input
3.6 V Input
4.2 V Input
4.2
4.1
3
3.5
Input Voltage (V)
4
4.5
0
0.5
1
VOUT = 5.1 V (TPS61235P), CC pin connected to GND
5.2
5.7
Output Voltage (V)
Output Voltage (V)
5.9
5
4.9
2.7 V Input
3.3 V Input
3.6 V Input
4.2 V Input
4.5
5
D001
5.5
5.3
5.1
2.7 V Input
3.3 V Input
3.6 V Input
4.2 V Input
5 V Input
4.9
4.7
4
Figure 35. Load Regulation
5.3
5.1
2
2.5
3
3.5
Output Current (A)
VOUT = 4.5 V (TPS61236P), CC pin connected to GND
Figure 34. Maximum Load Capability after Startup
4.8
1.5
D001
4.7
0
0.5
1
1.5
2
2.5
3
3.5
Output Current (A)
4
4.5
5
0
0.5
1
D001
VOUT = 5.1 V (TPS61235P), CC pin connected to GND
1.5
2
2.5
3
3.5
Output Current (A)
4
4.5
5
D001
VOUT = 5.5 V (TPS61236P), CC pin connected to GND
Figure 36. Load Regulation
Figure 37. Load Regulation
VOUT (5 V DC Offset) 50 mV/div
IOUT 2 A/div
Inductor Current 2 A/div
VIN = 3.6 V, VOUT = 5 V, IOUT from 0 mA to 4 A
Figure 38. Load Sweep
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
25
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
10 Power Supply Recommendations
The device is designed to operate from an input voltage supply range between 2.3-V and (VOUT – 0.6)-V. This
input supply must be well regulated. If the input supply is located more than a few inches from the converter,
additional bulk capacitance may be required in addition to the ceramic bypass capacitors. An electrolytic or
tantalum capacitor with a value of 47-μF is a typical choice in this circumstance.
26
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
11 Layout
11.1 Layout Guidelines
For all switching power supplies, layout is an important step in the design, especially at high peak currents and
high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as well
as EMI problems. Therefore, use wide and short traces for the main current paths and the power ground tracks.
The input capacitor, output capacitor, and the inductor should be placed as close as possible to the IC. Use a
common ground node for power ground and a different one for control/analog ground to minimize the effects of
ground noise. Connect these ground nodes near the ground pins of the IC. The most critical current path for all
boost converters is from the switching FET, through the synchronous FET, the output capacitors, and back to the
ground of the switching FET. Therefore, the output capacitors and their traces should be placed on the same
board layer as the IC and as close as possible between the VOUT and PGND pins of the IC.
See Figure 39 for the recommended layout.
11.2 Layout Example
The bottom layer is a large GND plane connected by vias.
PGND
L
C1
VIN
C4
C3
SW
R3
PGND
SW
VIN
CC
CC
AGND
FB
EN
VOUT
INACT
R2
AGND
PGND
C2
FB
VOUT
C5
Top Layer
R1
R4
Bottom Layer
EN INACT VDD
Figure 39. Layout Recommendation
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
27
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
11.3 Thermal Considerations
The maximum IC junction temperature should be restricted to 125°C under normal operating conditions.
Calculate the maximum allowable dissipation, PD(max), and keep the actual power dissipation less than or equal to
PD(max). The maximum power dissipation limit is determined using:
125 TA
PD(max)
R TJA
(9)
Where:
TA is the maximum ambient temperature for the application.
RθJA is the junction-to-ambient thermal resistance given in the Thermal Information table.
The TPS6123x handles high power conversion so requires special attention to the power dissipation. The
junction-to-ambient thermal resistance of a package in an application greatly depends on the PCB type and
layout, and many system-dependent factors such as thermal coupling, airflow, added heat sinks and convection
surfaces, and the presence of other heat-generating components also affect the power-dissipation limits.
Two common basic approaches to enhancing thermal performance are listed below.
• Increase the power dissipation capability of the PCB. It is necessary to have sufficient copper area as heat
sinks. For DC voltage nodes like VIN, VOUT, and PGND, make the copper area as large as possible. Multiple
vias are helpful in further reducing thermal stress. It is also a good practice to have thick copper layers in
order to minimize the PCB conduction loss and thermal impedance.
• Introduce airflow in the system.
For more details on how to use the thermal parameters in the Thermal Information table, check the Thermal
Characteristics Application Note (SZZA017) and the IC Package Thermal Metrics Application Note (SPRA953).
28
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
TPS61235P, TPS61236P
www.ti.com
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
12 Device and Documentation Support
12.1 Device Support
12.1.1 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.
12.2 Documentation Support
12.2.1 Related Documentation
For related documentation see the following:
• Optimizing Transient Response of Internally Compensated dc-dc Converters With Feedforward Capacitor
Application Report (SLVA289)
• Thermal Characteristics of Linear and Logic Packages Using JEDEC PCB Designs Application Report
(SZZA017)
• Semiconductor and IC Package Thermal Metrics Application Report (SPRA953)
12.3 Related Links
The table below lists quick access links. Categories include technical documents, support and community
resources, tools and software, and quick access to sample or buy.
Table 5. Related Links
PARTS
PRODUCT FOLDER
SAMPLE & BUY
TECHNICAL
DOCUMENTS
TOOLS &
SOFTWARE
SUPPORT &
COMMUNITY
TPS61235P
Click here
Click here
Click here
Click here
Click here
TPS61236P
Click here
Click here
Click here
Click here
Click here
12.4 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me 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.
12.5 Community Resources
The following links connect to TI community resources. Linked contents are 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.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
12.6 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.7 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
Submit Documentation Feedback
29
TPS61235P, TPS61236P
SLVSCK4A – SEPTEMBER 2015 – REVISED MAY 2016
www.ti.com
12.8 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 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.
30
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TPS61235P TPS61236P
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
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)
TPS61235PRWLR
ACTIVE
VQFN-HR
RWL
9
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
ZGEI
TPS61235PRWLT
ACTIVE
VQFN-HR
RWL
9
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
ZGEI
TPS61236PRWLR
ACTIVE
VQFN-HR
RWL
9
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
ZGFI
TPS61236PRWLT
ACTIVE
VQFN-HR
RWL
9
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
ZGFI
(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
