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