A6213 and A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
FEATURES AND BENEFITS
DESCRIPTION
• AEC-Q100 qualified
• Supply voltage 6 to 48 V
• True average output current control
• 3 A maximum output over operating temperature range
(1.5 A for A6213-1)
• Cycle-by-cycle current limit
• Integrated MOSFET switch
• Dimming via direct logic input or power supply voltage
• Internal control loop compensation
• Undervoltage lockout (UVLO) and thermal shutdown
protection
• Low power shutdown (1 µA typical)
• Robust protection against:
▫ Adjacent pin-to-pin short
▫ Pin-to-GND short
▫ Component open/short faults
The A6213 is a single IC switching regulator that provides
constant-current output to drive high-power LEDs. It integrates
a high-side N-channel DMOS switch for DC-to-DC step- down
(buck) conversion. A true average current is output using a
cycle-by-cycle, controlled on-time method.
PACKAGE: 8-pin SOICN with exposed
thermal pad (suffix LJ):
APPLICATIONS:
Not to scale
Output current is user-selectable by an external current sense
resistor. Output voltage is automatically adjusted to drive
various numbers of LEDs in a single string. This ensures the
optimal system efficiency.
LED dimming is accomplished by a direct logic input pulsewidth modulation (PWM) signal at the enable pin.
The device is provided in a compact 8-pin narrow SOIC package
(suffix LJ) with exposed pad for enhanced thermal dissipation.
It is lead (Pb) free, with 100% matte-tin leadframe plating.
Automotive lighting
• Daytime running lights
• Front and rear fog lights
• Turn/stop lights
• Map light
• Dimmable interior lights
TYPICAL APPLICATION CIRCUIT
VIN (6 to 48 V)
GND
C1
1
8
SW
A6213
R1 2
7
TON
BOOT
3
6
EN
PAD GND
4
VCC 5
CS
VIN
C4
LED+
D1
...
EN
L1
C5
Enable/PWM Dimming
(100 Hz to 2 kHz)
LED–
RSENSE
A62131-DS, Rev. 9
MCO-0000885
January 21, 2013
June 11, 2021
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
SELECTION GUIDE
Part Number
Operating Ambient
Temperature, TA
Package
Packing
A6213KLJTR-T
–40°C to 125°C
8-pin SOICN with exposed thermal pad
3000 pieces per 13-in reel
A6213KLJTR-1-T
–40°C to 125°C
8-pin SOICN with exposed thermal pad
3000 pieces per 13-in reel
ABSOLUTE MAXIMUM RATINGS
Characteristic
Symbol
Rating
Unit
VIN
–0.3 to 50
V
VBOOT
–0.3 to VIN + 8
V
–1.5 to VIN + 0.3
V
–0.3 to 7
V
Supply Voltage
Bootstrap Drive Voltage
Notes
Switching Voltage
VSW
Linear Regulator Terminal
VCC
Enable and TON Voltage
VEN , VTON
–0.3 to VIN + 0.3
V
VCS
–0.3 to 7
V
TJ(max)
150
°C
Tstg
–55 to 150
°C
Current Sense Voltage
Maximum Junction Temperature
Storage Temperature
VCC to GND
THERMAL CHARACTERISTICS*: may require derating at maximum conditions; see application section for optimization
Characteristic
Symbol
Package Thermal Resistance
(Junction to Ambient)
RθJA
Package Thermal Resistance
(Junction to Pad)
RθJP
Test Conditions*
Value
Unit
On 4-layer PCB based on JEDEC standard
35
°C/W
On 2-layer generic test PCB with 0.8 in.2 of copper area each side
62
°C/W
2
°C/W
*Additional thermal information available on the Allegro website.
Pinout Diagram
Terminal List Table
8
VIN 1
7
TON 2
SW
BOOT
PAD
EN 3
CS 4
6
5
GND
VCC
Number
Name
1
VIN
Supply voltage input terminals
Function
2
TON
Regulator on-time setting resistor terminal
3
EN
Logic input for Enable and PWM dimming
4
CS
Drive output current sense feedback
5
VCC
Internal linear regulator output
6
GND
Ground terminal
7
BOOT
DMOS gate driver bootstrap terminal
8
SW
Switched output terminals
–
PAD
Exposed pad for enhanced thermal dissipation;
connect to GND
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
2
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
FUNCTIONAL BLOCK DIAGRAM
CVCC
CBOOT
VCC
VIN
VIN
BOOT
L1
LED String
D1
SW
VREG 5.3 V
VCC
UVLO
~VOUT
On-Time
Current
Generator
TON
Average
On-Time
Timer
Off-Time
Timer
Gate Drive
UVLO
Shutdown
RON
Dithering
(±5%)
Level Shift
EN
+
IC and Driver
Control Logic
CCOMP
0.2 V
Current Limit
Off-Time
Timer
–
–
Buck Switch
Current Sense
+
VIL = 0.4 V
VIH = 1.8 V
+
+
VCC UVLO
–
–
Thermal
Shutdown
ILIM
CS
PAD
GND
RSENSE
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
3
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
ELECTRICAL CHARACTERISTICS: Valid at VIN = 24 V, TA = –40°C to 125°C, typical values at TA = 25°C, unless otherwise noted
Characteristics
Symbol
Input Supply Voltage
VIN Undervoltage Lockout Threshold
VIN Undervoltage Lockout Hysteresis
VIN
VUVLO
IIN
IINSD
Buck Switch Current Limit Threshold
ISWLIM
Buck Switch On-Resistance
R
BOOT Undervoltage Lockout
Threshold
BOOT Undervoltage Lockout
Hysteresis
DS(on)
VBOOTUV
VCS = 0.5 V, EN = high
EN shorted to GND
tOFFmin
Switching Minimum On-Time
tONmin
tON
Min.
Typ.
Max.
Unit
6
–
48
V
–
5.3
–
V
–
150
–
mV
–
5
–
mA
–
1
10
µA
A6213
3.0
4.0
5.0
A
A6213-1
1.9
2.2
2.5
A
–
0.25
0.4
Ω
1.7
2.9
4.3
V
–
370
–
mV
–
110
150
ns
VBOOT = VIN + 4.3 V, TA = 25°C, ISW = 1 A
VBOOT to VSW increasing
VBOTUVHYS VBOOT to VSW decreasing
Switching Minimum Off-Time
Selected On-Time
VIN increasing
VUVLO_HYS VIN decreasing
VIN Pin Supply Current
VIN Pin Shutdown Current
Test Conditions
VCS = 0 V
VIN = 24 V, VOUT = 12 V, RON = 137 kΩ
–
110
150
ns
800
1000
1200
ns
187.5
200
210
mV
–
0.9
–
µA
5.1
5.4
5.7
V
5
20
–
mA
–
–
V
REGULATION COMPARATOR AND ERROR AMPLIFIER
Load Current Sense Regulation
Threshold [1]
VCSREG
VCS decreasing, SW turns on
Load Current Sense Bias Current
ICSBIAS
VCS = 0.2 V, EN = low
INTERNAL LINEAR REGULATOR
VCC Regulated Output
VCC Current Limit [2]
VCC
ICCLIM
0 mA < ICC < 5 mA, VIN > 6 V
VIN = 24 V, VCC = 0 V
ENABLE INPUT
Logic High Voltage
Logic Low Voltage
VIH
VEN increasing
1.8
VIL
VEN decreasing
–
–
0.4
V
EN Pin Pull-down Resistance
RENPD
VEN = 5 V
–
100
–
kΩ
Maximum PWM Dimming Off-Time
tPWML
Measured while EN = low, during dimming
control, and internal references are powered-on
(exceeding tPWML results in shutdown)
10
17
–
ms
THERMAL SHUTDOWN
Thermal Shutdown Threshold
TSD
–
165
–
°C
Thermal Shutdown Hysteresis
TSDHYS
–
25
–
°C
In test mode, a ramp signal is applied at CS pin to determine the CS pin regulation threshold voltage. In actual application, the average CS pin
voltage is regulated at VCSREG regardless of ripple voltage.
[2] The internal linear regulator is not designed to drive an external load.
[1]
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
4
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
CHARACTERISTIC PERFORMANCE
VIN
VIN
VOUT
VOUT
C1,C2
C1,C2
iLED
C3
C4
iLED
C3
VEN
C4
VEN
t
t
Panel 1B. VIN = 24 V
Panel 1A. VIN = 19 V
VIN
VOUT
C1,C2
iLED
C3
C4
VEN
t
Panel 1C. VIN = 30 V
Figure 1: Startup waveforms from off-state at various input voltages;
note that the rise time of the LED current depends on input/output voltages, inductor value, and switching frequency
• Operating conditions: LED voltage = 15 V, LED current = 1.3 A, R1 = 63.4 kΩ (frequency = 1 MHz in steady state),
VIN = 19 V (panel 1A), 24 V (panel 1B) and 30 V (panel 1C)
• Oscilloscope settings: CH1 (Red) = VIN (10 V/div), CH2 (Blue) = VOUT (10 V/div),
CH3 (Green) = iLED (500 mA/div), CH4 (Yellow) = Enable (5 V/div), time scale = 50 µs/div
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
5
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
VIN
VOUT
C1,C2
iLED
C3
C4
VEN
t
Panel 2A. Duty cycle = 50% and time scale = 1 ms/div
VIN
VOUT
C1,C2
iLED
C3
C4
VEN
t
Panel 2B. Duty cycle = 2% and time scale = 50 µs/div
Figure 2: PWM operation at various duty cycles; note that there is no startup delay during PWM dimming operation
• Operating conditions: at 200 Hz, VIN = 24 V, VOUT = 15 V, R1 = 63.4 kΩ, duty cycle = 50% (panel 2A) and 2% (panel 2B)
• CH1 (Red) = VIN (10 V/div), CH2 (Blue) = VOUT (10 V/div),
CH3 (Green) = iLED (500 mA/div), CH4 (Yellow) = Enable (5 V/div), time scale = 1 ms/div (panel 2A) and 50 µs/div (panel 2B)
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
6
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
95
95
VIN = 24 V, VOUT = 15 V
VIN = 12 V, VOUT = 5.5 V
85
VIN = 12 V, VOUT = 3.5 V
80
fSW = 500 kHz
90
Efficiency, η (%)
Efficiency, η (%)
90
75
fSW = 1 MHz
85
fSW = 2 MHz
80
75
70
70
0
0.5
1.0
1.5
2.0
2.5
3.0
0
0.5
LED Current, iLED (A)
1.0
1.5
2.0
2.5
3.0
LED Current, iLED (A)
Figure 3: Efficiency versus LED Current at various LED voltages
Operating conditions: fSW = 1 MHz
Figure 4: Efficiency versus LED Current at various switching
frequencies. Operating conditions: VIN = 12 V, VOUT = 5.5 V
LED Current (A)
1
0.1
iLED = 3 A
iLED = 2 A
iLED = 1.4 A
0.01
0.001
0.1
1
10
100
Duty Cycle (%)
Figure 5. Average LED Current versus PWM dimming percentage
Operating conditions: VIN = 12 V, VOUT = 3.5 V, fSW = 1 MHz, fPWM = 200 Hz, L = 10 µH
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
7
A6213 and
A6213-1
Automotive-Grade, Constant-Current
PWM Dimmable Buck Regulator LED Driver
FUNCTIONAL DESCRIPTION
The A6213 is a buck regulator designed for driving a high-current
LED string. It utilizes average current mode control to maintain
constant LED current and consistent brightness. The LED current
level is easily programmable by selection of an external sense
resistor, with a value determined as follows:
iLED = VCSREG / RSENSE
where VCSREG = 0.2 V typical.
Switching Frequency
The A6213 operates in fixed on-time mode during switching. The
on-time (and hence switching frequency) is programmed using
an external resistor connected between the VIN and TON pins, as
2.2
2.0
1.8
fsw (MHz)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
20
40
60
80
100 120 140 160 180 200 220 240 260
RTON (kΩ)
Figure 6: Switching Frequency versus RTON Resistance
• During SW on-time:
iRIPPLE = [(VIN – VOUT) / L] × tON = [(VIN – VOUT) / L] × T × D
where D = tON / T.
• During SW off-time:
iRIPPLE = [(VOUT – VD) / L] × tOFF = [(VOUT – VD) / L] × T × (1 – D)
Therefore (simplified equation for Output Voltage):
VOUT = VIN × D – VD × (1 – D)
If VD
