Abstract: A current-to-frequency converter which uses current balancing and pulse width modulation. An analog signal from a measurement instrument, such as an accelerometer, is integrated and transmitted to a pulse width modulator. The output from the pulse width modulator controls feedback signals which in turn control current balancing. The output of the pulse width modulating circuit is also connected to a counter which provides a digital output.

Abstract: A bipolar current source which provides negative and positive currents have been equalized by magnitude. During the majority of the time, the bipolar current source is operating both positive and negative currents are output by the circuit. For a small percentage of the time, both the negative and positive currents are fed into current equalizing circuitry. The current equalizing circuitry generates a feedback signal which is transmitted to either the positive or negative current sources and the magnitude of that current is adjusted until the magnitudes of the positive and negative currents are equal. The bipolar current source then resumes normal operation.