SWITCHING CONVERTER WITH CONSTANT ON-TIME CONTROLLER THEREOF

摘要

A control circuit for controlling a switching circuit has a ramp compensation circuit, a DC calibration circuit, a comparison circuit and a logic circuit. The ramp compensation circuit generates a ramp compensation signal. The DC calibration circuit generates a DC calibration signal by sampling and holding the ramp compensation signal. The comparison circuit generates a comparison signal according to the ramp compensation signal, a feedback signal representative of an output voltage of the switching converter, a reference signal and the DC calibration signal. The logic circuit generates a control signal to control the switching circuit according to an on-time signal and the comparison signal.

主权项

1. A control circuit for controlling a switching circuit, wherein the switching circuit comprises a switch, and the switching circuit is configured to convert an input voltage into an output voltage, the control circuit comprises:
an on-time generating circuit configured to generate an on-time signal; a ramp compensation circuit configured to generate a ramp compensation signal; a DC calibration circuit configured to generate a DC calibration signal by sampling the ramp compensation signal during a transition period when the switch transits from a first state into a second state and holding the sampled ramp compensation signal until the next transition period; a comparison circuit electrically coupled to the ramp compensation circuit and the DC calibration circuit, wherein the comparison circuit is configured to generate a comparison signal based on a feedback signal representative of the output voltage, a reference signal, the ramp compensation signal and the DC calibration signal; and a logic circuit electrically coupled to the on-time generating circuit and the comparison circuit, wherein the logic circuit is configured to generate a control signal to control the switching circuit based on the on-time signal and the comparison signal.