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1. (WO2018102370) NOISE REDUCTION IN VOLTAGE REFERENCE SIGNAL

Pub. No.:    WO/2018/102370    International Application No.:    PCT/US2017/063639
Publication Date: Fri Jun 08 01:59:59 CEST 2018 International Filing Date: Thu Nov 30 00:59:59 CET 2017
IPC: H03M 1/08
H03M 1/12
Applicants: CIRRUS LOGIC INTERNATIONAL SEMICONDUCTOR LTD.
ZANBAGHI, Ramin
DAS, Tejasvi
MELANSON, John, L.
THOMSEN, Axel
Inventors: ZANBAGHI, Ramin
DAS, Tejasvi
MELANSON, John, L.
THOMSEN, Axel
Title: NOISE REDUCTION IN VOLTAGE REFERENCE SIGNAL
Abstract:
A variable resistor may be coupled between a reference voltage source and components of an integrated circuit to reduce issues relating to thermal noise from a reference voltage signal generated by the reference voltage source. The variable resistor may be set to a low level during a first time period and a high level during a second time period, in which the time periods correspond to a sampling period of a switched-capacitor circuit. The low resistance time period may allow quick settling of an input reference voltage signal, whereas the high resistance time period may reduce a bandwidth of noise on a sampling capacitor coupled to the reference voltage signal. The variable resistor and switched-capacitor network may be used in an analog-to-digital converter (ADC), such as in audio circuits.