Voltage sensing circuit for converter

摘要

A voltage sensing circuit of a converter senses input and output voltages of a converter with only one sensing circuit. The voltage sensing circuit is capable of reducing the number of the components for a controller and the volume thereof to save cost, and detecting whether the discontinuous mode (DCM) is entered or not, thereby to apply a separate control algorithm thereto when the DCM is entered.

主权项

1. A voltage sensing circuit of a converter, in which an inductor and a diode are connected serially between an input terminal of the converter and an output terminal of the converter, comprising an operational amplifier connected to both terminals of the inductor and configured to detect voltages at both terminals of the inductor of the converter,
wherein a full-wave rectification bridge is interposed between the inductor and the operational amplifier, and two input terminals of the operational amplifier are connected to the full-wave rectification bridge, wherein an output voltage and an input voltage of the converter are sensed alternatively according to a maximum value and a minimum value of a voltage at an output terminal of the operational amplifier, respectively, wherein the maximum value is proportional to the output voltage of the converter and the minimum value is proportional to the input voltage of the converter, and wherein both the output voltage and an output current of the operational amplifier are 0s, when a discontinuous mode is entered.