PWM to 0-2.5 Vdc with clamping input - inverting

Converts a PWM signal to a 0 to 2.5 Vdc voltage. A clamping input overrides the converter output bringing the main output to 4.5V. Circuit built to drive a FL5160MX phase-cut dimmer controller. In the real circuit both inputs will be driven by microcontroller GPIOs through optocouplers.