A6269 Automotive LED Driver Array Circuit Diagram

    This A6269 Automotive LED Driver Array Circuit was designed by Allegro MicroSystems for use in automotive applications using 12 or 24 volt supplies.
    The toggle action of the SW input is reset to off every time power is applied. From this stage, apply EN = high signal to turn on the LED and EN = low signal to turn off the LED.
    At power-up (EN connected to VIN), there is a short turn-on delay tON before the current starts to rise. The rise time of the current will be limited by the internal current slew rate control.
    This circuit uses a manual switch to turn a light on or off. When the lights are off, the central lighting control unit can send a PWM signal to gradually dim the lights before turning off completely. The interaction of the two control inputs is explained as follows:
    An internal trigger (and thus LED light) starts from the off state, ensured by a power-on reset.
    The lamp can be turned on by EN = high or by a momentary toggle (high-low-high) of the SW input.
    If the lamp was originally turned on by EN=High, it can be turned off by EN=Low. This allows PWM dimming of the light.
    If the lamp is initially lit by the SW input, it remains lit regardless of the state of EN. only when the other light goes out
    Momentary switching is received on SW input or power down.
    Allegro MicroSystems uses the state diagram below to graphically explain and represent the behavior described above.
    THTH sets the thermal monitor threshold TJM where the output current begins to decrease as temperature increases. Connecting THTH directly to GND will disable thermal monitoring (see datasheet).
    Rref = K/ILAx ; where K is 30 and ILAx (nominal output current per Lax)