SAMPLE-AND-HOLD CIRCUIT FOR GENERATING A VARIABLE SAMPLE SIGNAL OF A POWER CONVERTER AND METHOD THEREOF

摘要

A sample-and-hold circuit includes a first voltage generation unit, a second voltage generation unit, a stabilization capacitor. The first voltage generation unit generates a first voltage according to a first predetermined delay time and a voltage corresponding to an auxiliary winding of a power converter. The second voltage generation unit generates a second voltage according to K multiple of a discharge time of a secondary side of the power converter during a previous period of the power converter and the voltage, wherein K<1. When a sum of the K multiple of the discharge time and a second predetermined delay time leads a first valley of the voltage corresponding to a current period of the power converter, the second voltage generation unit outputs the second voltage. When the sum lags the first valley, the first voltage generation unit outputs the first voltage.

主权项

1. A sample-and-hold circuit for generating a variable sample signal of a power converter, comprising:
a first voltage generator for generating a first voltage according to a first reference current; a second voltage generator for generating a second voltage, wherein the second voltage corresponds to a turning-on time of a power switch of the power converter; and a comparator for generating a sample signal to a control circuit within the power converter according to the first voltage and the second voltage.