CONSTANT-VOLTAGE AND CONSTANT-CURRENT BUCK CONVERTER AND CONTROL CIRCUIT

摘要

A control circuit is provided for a buck converter that includes at least an inductor coupled to an output of the buck converter. The control circuit includes a power switch configured for coupling to a line voltage and configured for charging the inductor, an input line voltage sampling circuit, and a constant-voltage (CV) and constant-current (CC) control module coupled to the power switch. During a charging period of the inductor, the CV and CC control module is configured to control the power switch to provide a constant output current by maintaining a constant peak inductor current, even when the input line voltage changes. During a discharging period of the inductor, the CV and CC control module is configured to monitor the sensed output voltage to control the power switch to provide a constant output voltage.

主权项

1. A control circuit for a buck converter, the buck converter including at least an inductor coupled to an output of the buck converter, the control circuit comprises:
a power switch configured for coupling to a line voltage and configured for charging the inductor; an input line voltage sampling circuit; and a constant-voltage (CV) and constant-current (CC) control module coupled to the power switch, wherein the CV and CC control module is configured to:
during a charging period of the inductor, control the power switch to provide a constant output current by maintaining a constant peak inductor current when the input line voltage changes; andduring a discharging period of the inductor, to monitor the sensed output voltage to control the power switch to provide a constant output voltage.