公开(公告)号：US10528070B2

公开(公告)日：2020-01-07

申请号：US15969175

申请日：2018-05-02

Applicant: Analog Devices Global Unlimited Company

Inventor： Michael C. W. Coln ,  Michael Mueck ,  Quan Wan ,  Sandeep Monangi

IPC: G05F3/26 ,  H03F1/30 ,  H03F1/02 ,  H03F3/45 ,  H03M1/12 ,  H03M1/46

Abstract: A low-noise, low-power reference voltage circuit can include an operational transconductance amplifier (OTA) with inputs coupled to a temperature-compensated voltage, such as can be provided by source-coupled first and second field-effect transistors (FETs) having different threshold voltages. A capacitive voltage divider can feed back a portion of a reference voltage output by the OTA to the inputs of the OTA to help establish or maintain the temperature-compensated voltage across the inputs of the OTA. A switching network can be used, such as initialize the capacitive voltage divider or other capacitive feedback circuit, such as during power-down cycles, or when resuming powered-on cycles. A switch can interrupt current to the OTA during the power-down cycles to save power. The cycled voltage reference circuit can provide a reference voltage to an ADC reservoir capacitor. Powering down can occur during analog input signal sampling, during successive approximation routine (SAR) conversion, or both.

公开(公告)号：US20190339730A1

公开(公告)日：2019-11-07

申请号：US15969175

申请日：2018-05-02

Applicant: Analog Devices Global Unlimited Company

Inventor： Michael C.W. Coln ,  Michael Mueck ,  Quan Wan ,  Sandeep Monangi

IPC: G05F3/26 ,  H03F1/02 ,  H03F1/30 ,  H03F3/45 ,  H03M1/46 ,  H03M1/12

Abstract: A low-noise, low-power reference voltage circuit can include an operational transconductance amplifier (OTA) with inputs coupled to a temperature-compensated voltage, such as can be provided by source-coupled first and second field-effect transistors (FETs) having different threshold voltages. A capacitive voltage divider can teed back a portion of a reference voltage output by the OTA to the inputs of the OTA to help establish or maintain the temperature-compensated voltage across the inputs of the OTA. A switching network can be used, such as initialize the capacitive voltage divider or other capacitive feedback circuit, such as during power-down cycles, or when resuming powered-on cycles. A switch can interrupt current to the OTA during the power-down cycles to save power. The cycled voltage reference circuit can provide a reference voltage to an ADC reservoir capacitor. Powering down can occur during analog input signal sampling, during successive approximation routine (SAR) conversion, or both.