A Simple Current-To-Time Converter

A simple circuit based on one CMOS two-input or gate serving as a voltage discriminator, a waveshaping circuit, and a logic circuit is described. It produces pulses with a pulse pause proportional to the reciprocal of its input current. If covers three decades, 1 ??A to 1 mA, with the conversion error less than 1 percent or five decades, 1 ??A to 10 mA, with the error less than 3 percent.