This circuit is designed to replace a single-filament incandescent bulb in an automobile tail light, brake light, turn signal, reverse light, or interior light (dome light, map light). It operates at approximately 600kHz, and regulates the current in the LED at 350mA from inputs of 9V to 40V. This makes it suitable for standard passenger cars and trucks with 8V-16V batteries as well as freight trucks, tow trucks, fork lifts, and other vehicles that use a double lead-acid battery system (16V-32V). Diode D1 provides reverse battery protection, and the LM5007 can withstand inputs voltages of up to 75V. This circuit does not need additional protection from 'load dump' events of up to 75V.
Although not shown, the brightness of the LED can be dimmed with a PWM input by placing a signal-level NFET from the RON pin to ground and driving the gate with the PWM signal. This circuit is also compatible with 100Hz PWM of the input voltage for 'theater dimming' of interior lights.
Please note that A1 in the schematic is shown as U2 in the PCB layout.
Schematic
Example Schematic Showing Connection for all Components.
Example Schematic Showing Connection for all Components.
