A6271 Datasheet | Allegro MicroSystems

Features AND BENEFITS - Automotive AEC-Q100 qualified - Constant-current LED drive - 4.2 to 50 V supply - 53.3 V maximum LED string voltage - Boost, buck-boost, and buck switching converters - Programmable switching frequency 70 to 700 k Hz - PWM-controlled PMOS driver allows accurate LED current control at low duty cycles - Dimming via external PWM, internal PWM and/or analog dimming - Frequency dither scheme for effective spread spectrum to reduce EMI - prehensive fault protection and fault flag PACKAGE: 16-Pin e TSSOP (LP) with Exposed Thermal Pad DESCRIPTION The A6271 is a DC-DC converter controller, providing a programmable constant-current output for driving high-power LEDs in series. The controller is based on a programmable fixed-frequency, peak current-mode control architecture. The DC-DC converter can be configured in a myriad of different switching configurations including boost, buck-boost, and buck (ground-referenced switch). The A6271 provides a cost-effective solution using an external logic-level MOSFET and minimum additional external ponents. The maximum LED current is set with a single external sense resistor and can be accurately modulated using a current reference input (analog control). External PWM dimming is possible via the PWMIN input, which also provides a shutdown mode. As an alternative, an internal PWM dimming circuit can be used by programming the PWMIN and DR pins. Either PWM scheme controls the PWMOUT output which drives an external p-channel MOSFET connected in series with the LED string. This MOSFET is also used to isolate the load during certain fault conditions, including output shorts to ground. Continued on next page... Not to scale APPLICATIONS - Automotive high-power LED lighting systems - Fog lights, reversing lights, daytime running lights, position lights, headlights VBAT C1 4.7 µF C2 4.7 µF L1 56 µH D2 C7 47 n F R5 150...