555 Makes handy Voltage-to-Time Converter: 02/01/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Circuit Converts Pulse Width to Voltage #2: 10/28/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit. --- The circuit is optimized for a positive-going pulse width of1 to2 msec, repeating at intervals of approximately17 msec. The output produces a voltage of0.95V for a1-msec pulse to2.25V for a2-msec pulse.

Circuit Converts Pulse Width to Voltage: 10/25/01 EDN-Design Ideas / The circuit converts pulse information to a clean dc voltage by the end of a single incoming pulse. In another technique, an RC filter can convert a PWM signal to an averaged dc voltage, but this method is slow in responding. Converting low-duty-cycle pulse information is slower yet.