The A6265, A6266 and A6267 from Allegro MicroSystems Europe are a new family of automotive-grade, high-current LED driver ICs with extensive diagnostics and protection features.
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The new devices, which are fully qualified to the AEC-Q100 Grade 0 Automotive Specification, are DC-DC converter controllers, with the
A6265/A6267 configurable as either boost or buck-boost converters and the
A6266 as a boost converter only.
All the new driver ICs provide a programmable constant current output for driving high power LEDs in series, ensuring identical currents and uniform brightness. Each is capable of driving up to 15 LEDs at currents of 1 A or higher based on the external logic-level MOSFET.
With the A6267, the 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 at shutdown and no inrush current at power-up.
The A6265, A6266 and A6267 provide a robust, high-performance, cost-effective solution using an external 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. The dimming schemes for the A6265 and A6267 differ slightly, offering flexibility to the designer with a choice of drop-in devices.
Integrated diagnostics and two fault outputs give indication of under-voltage, chip over-temperature, output open circuit, LED short circuit and LED under-current, and can be configured to provide short-circuit to supply and short-circuit to ground protection for the LED connections.
The ability to detect one or more short-circuited LEDs is a unique feature of all the devices.
