Automatic amplitude control circuit

摘要

The present invention provides an automatic amplitude control circuit, including an oscillator, a collecting module, a first analog current generating module, a second analog current generating module, and a numerical control current generating module. According to this automatic amplitude control circuit, a low-noise numerical control bias current can be provided for the oscillator.

主权项

1. An automatic amplitude control circuit, comprising:
an oscillator configured to generate an oscillation frequency signal having an oscillation amplitude; a collecting module configured to generate a voltage difference between the oscillation amplitude and a reference voltage; a first analog current generating module configured to:
convert the voltage difference into a first bias current, andduring a first time period, provide the first bias current for the oscillator, so as to control the oscillation amplitude of the oscillation frequency signal that is generated by the oscillator; a second analog current generating module configured to convert the voltage difference into a second bias current, wherein the first bias current is equal to the second bias current; and a numerical control current generating module configured to:
adjust, during the first time period and according to the second bias current, a numerical control current output by the numerical control current generating module, to enable the numerical control current to be consistent with the second bias current, andduring a second time period, provide the numerical control current for the oscillator to serve as a bias current, so as to control the oscillation amplitude of the oscillation frequency signal that is generated by the oscillator, wherein the second time period follows the first time period.