Switching circuit with reverse current prevention for use in Buck converter

Abstract

A switching circuit with reverse current prevention for use in a Buck converter includes a power switch coupled to a coupling node, which is an interconnection point of a power switch, an inductor and a freewheeling diode of the Buck converter. The inductor is coupled between the coupling node and an output of the Buck converter, and the freewheeling diode is coupled between coupling node and an output return of the Buck converter. A controller is coupled to receive a feedback signal to control switching of the power switch to regulate a transfer of energy from the input to the output of the Buck converter. A reverse current prevention circuit is coupled to detect a reverse current condition of the power switch to generate an inhibit signal to inhibit the power switch from receiving a drive signal to prevent a reverse current through the power switch.

Description

technical field [0001] The present disclosure relates generally to power converters, and more particularly to non-insulated buck converters. Background technique [0002] Traditional wall sockets typically deliver high voltage alternating current (AC) power that needs to be converted to direct current (DC) power before being used to power many electronic devices. Switching power converters are commonly used to convert high voltage AC power to regulated DC power due to their high efficiency, small size, light weight and safety features. For example, switching power converters are commonly used in drive circuits in the lighting industry to provide DC power to various types of lamps, such as compact fluorescent lamps (CFL), halogen lamps, or light-emitting diode (LED) lamps . [0003] Output regulation of switching power converters is typically provided by sensing a feedback signal from the output of the converter and controlling the power converter in a closed loop. Under d...

AI Technical Summary

Problems solved by technology

[0007] A known issue in buck converters is the risk of failure due to reverse current flow through the buck power switch when a negative voltage appears on the switch

This condition may adversely affect the operation of the power converter and eventually lead to failure

Specifically, when the controller and power switches are located on a common die or in a single integrated circuit IC package, reverse current may flow through the substrate, which can lead to instability, controller latch-up, and in some cases power converter failure

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