A6268 Datasheet, PDF (1/19 Pages) Allegro MicroSystems – The A6268 is a DC-to-DC converter controller, providing a programmable constant current output for driving high power LEDs in series.

A6268
Automotive High Current LED Controller
Features and Benefits
▪ AEC Q100 Grade 0 Automotive Qualified
▪ Constant current LED drive
▪ 5 to 50 V supply
▪ Boost or buck-boost modes
▪ Drives up to 15 LEDs in series
▪ Programmable switching frequency 100 to 700 kHz
▪ Open LED overvoltage indication and protection
▪ Single and multiple LED short indication
▪ LED short to ground and supply protection
▪ PWM dimming control
▪ 10 μA shutdown current including LED leakage
Applications:
▪ Automotive high power LED lighting systems
▪ Fog lights, reversing lights, daytime running lights
▪ Headlights
Package: 16-pin TSSOP with exposed
thermal pad (suffix LP)
Not to scale
Description
The A6268 is a DC-to-DC converter controller, providing a
programmable constant current output for driving high power
LEDs in series. Driving the LEDs in series ensures identical
currents and uniform brightness. For automotive applications,
optimum performance is achieved when driving up to 15 LEDs
at currents up to 1 A.
The A6268 provides a cost-effective solution using an external
logic-level MOSFET and minimum additional external
components. The maximum LED current is set with a single
external sense resistor and can be modified using a current
reference input. Direct PWM control is possible via the Enable
input, which also provides a shutdown mode.
This DC-DC converter can be configured as a ground-referenced
boost converter or as a supply-referenced boost converter
providing buck-boost capability. The buck-boost topology used
ensures that there is no leakage path through the LEDs when
in shutdown and no inrush current at power-up.
Integrated diagnostics and two fault outputs give indication of
VIN and VREG undervoltage, chip overtemperature, output
open circuit, LED short circuit and LED undercurrent, and can
be configured to provide short to supply and short to ground
protection for the LED connections, LED overcurrent and
shorted LED string protection. A unique feature is the ability
to detect one or more shorted LEDs.
The device is provided in a 16-pin TSSOP package with exposed
thermal pad (suffix LP). It is lead (Pb) free, with 100% matte
tin leadframe plating.
Typical Application Diagrams
V_BAT 12 V or 24 V (50 V max)
Power net
Buck Boost Mode
V_BAT(min)
(V)
Maximum
Quantity of
LEDs
5
7
6
8
7
10
8
11
9
13
V_f of each LED = 3.5 V,
D(max) = 85%
Fault
Flags
Enable
VIN
VREG
LN
LP
FF1
FF2
A6268 ^LF
EN
SG
IREF
SP
CKOUT
OSC
SN
GND ^LA
V_BAT 12 V or 24 V (50 V max)
Power net
Boost Mode
V_BAT(min)
(V)
Maximum
Quantity of
LEDs
5
8
6
10
7
12
8
13
9
15
V_f of each LED = 3.5 V,
D(max) = 85%
Fault
Flags
Enable
VIN
VREG
LN
LP
FF1
FF2
A6268 ^LF
EN
SG
IREF
SP
CKOUT
OSC
SN
GND ^LA
Buck-Boost Mode
(Supply-referenced boost)
A6268-DS, Rev. 1
Boost Mode