Voltage sensing in isolated converters

摘要

A system for sensing voltage in an isolated converter includes an input circuit isolated from an output circuit using a first transformer, the first transformer having a primary coil and a secondary coil, wherein the output circuit includes an output inductor and an output capacitor, and wherein the input circuit includes a power source that provides power to the output circuit through the first transformer; a feedback winding coupled to the output inductor to form a second transformer; and a monitor circuit that calculates a voltage across the output capacitor using a voltage across the feedback winding, a voltage across the primary coil of the first transformer, a turns ratio of the first transformer, and a turns ratio of the second transformer in order to provide feedback to control the input circuit.

主权项

1. An isolated converter comprising:
a first transformer; an input circuit connected to a primary coil of the first transformer and having at least one switch for regulating power supplied to the primary coil; an output circuit connected to a secondary coil of the first transformer that receives power supplied by the input circuit via the first transformer and supplies received power to a load via an output inductor; a feedback winding coupled to the output inductor to form a second transformer; a monitor circuit that calculates a voltage supplied to the load using a voltage across the feedback winding, a voltage across the primary coil of the first transformer, a turns ratio of the first transformer, and a turns ratio of the second transformer, wherein the monitor circuit comprises:
a voltage divider that calculates a voltage across the secondary coil of the first transformer based upon the voltage across the primary coil of the first transformer and the turns ratio of the first transformer; anda summing circuit that calculates the voltage supplied to the load by the output circuit by subtracting the voltage across the feedback winding from the calculated voltage across the secondary coil of the first transformer; anda controller that controls the at least one switch based on the voltage calculated by the monitor circuit to regulate the power supplied to the primary coil.