Patent Number: 6,798,372

Title: Switched-capacitor frequency-to-current converter

Abstract: A frequency-to-current converter operative to convert a clock frequency to an output current is described; the frequency-to-current converter ensures that the output current increases linearly with the clock frequency. The frequency-to-current converter may be incorporated in analog-to-digital converters driven by clocks with variable frequencies. The frequency-to-current converter employs an integrator circuit, used to compare an input reference voltage and a current feedback into a sampling capacitor. At steady state, the feedback current is just sufficient to discharge the sampling capacitor to a fixed voltage. The core of the frequency-to-current conversion circuit includes one opamp, two capacitors, one feedback transistor and a few switches.

Inventors: Yang; Yaohua (Hillsboro, OR), Jiang; Ruoxin (Hillsboro, OR), Yin; Rumin (Hillsboro, OR)

Assignee: Maxim Integrated Products, Inc.

International Classification: H03M 1/60 (20060101); H03M 001/60 ()

Expiration Date: 09/28/2021