Voltage-to-Pulse Duration Converter

This is a circuit of Voltage-to-Pulse Duration Converter. This circuit is used to convert voltage into pulse duration by combining a timer IC and an OP Amp. This circuit can obtain accuracy up to better than 1%. The output signal is independent of the input voltage and still retain the original frequency. Here is the circuit:

Voltage-to-Pulse Duration Converter

[Source: Philips Semiconductors Application Note]