The circuit in Figure 1 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.
pulse information is slower yet.
The circuit in Figure 1 uses two low-input-biascurrent LT1880 op amps, IC2 and IC3, and an LTC202 quad analog switch, IC1A, IC1B, IC1C, and IC1D, to configure the integrator and sampleand- hold stages that convert a single pulse to a dc voltage. Th