公开(公告)号：US10298247B1

公开(公告)日：2019-05-21

申请号：US15919985

申请日：2018-03-13

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Louis Frew ,  Kapil Sharma ,  David Paul Singleton ,  Andrew James Howlett

IPC: H03K7/08 ,  H03M1/06

Abstract: This application relates to analog-to-digital converter (ADC) circuitry (200). A time-encoding modulator (TEM 201) has a comparator (104) and a loop filter (105) configured to generate a pulse-width-modulated (PWM) signal (SPWM) in response to an input signal (SIN) and a feedback signal (SFB). A controlled oscillator, such as a VCO (202) receives the PWM signal and generates an output oscillation signal (SOSC) with a frequency that varies based on a drive signal at a drive node (109), e.g. a drive node of a ring oscillator (107). The controlled oscillator (202) comprises at least one control switch (112) controlled by a switch control signal (S1) generated from the received PWM signal so as to control the drive strength of the drive signal applied to the drive node (109). The feedback signal (SFB) for the TEM (201) is derived from the controlled oscillator (202) so as to include any timing error between the PWM signal and the switch control signal (S1) applied to said control switch.