Power supply having a synchronous rectifier circuit for improved switching timing
First Claim
1. A synchronous rectifier comprising a rectifier diode (D);
- a transistor (T) having a control electrode, and a main current path between a first main electrode and a second main electrode of the transistor (T), which main current path is coupled in parallel with the rectifier diode (D); and
a control circuit (CT) coupled to the control electrode of the transistor (T), characterized in that the control circuit (CT) comprises an amplifier (AMP) having a first input coupled to the first main electrode of the transistor (T), a second input coupled to the second main electrode of the transistor (T), and an output coupled to the control electrode of the transistor (T), and a reference voltage source (RF1) is coupled in series with at least one of the inputs, i.e. the first and the second input, of the amplifier (AMP).
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Accused Products
Abstract
A power supply includes a transformer (TR) having a first winding (N1) for receiving an input signal (Ui) and a second winding (N2) for supplying an output signal (Uo). Switching means (SM) are coupled in series with the first winding (N1) for switching on and switching off a current through the first winding (N1). A parallel arrangement of a freewheel diode (D) and a field effect transistor (T) is coupled in series with the second winding (N2). The gate of the field effect transistor (T) is controlled from an amplifier (AMP). The amplifier (AMP) compares the drain-source voltage of the field effect transistor (T) with the voltage of a reference voltage source (RF1) and ensures that the drain-source voltage is equal to the voltage of the reference voltage source (RF1) as long as an adequate current flows in the second winding (N2).
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Citations
7 Claims
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1. A synchronous rectifier comprising a rectifier diode (D);
- a transistor (T) having a control electrode, and a main current path between a first main electrode and a second main electrode of the transistor (T), which main current path is coupled in parallel with the rectifier diode (D); and
a control circuit (CT) coupled to the control electrode of the transistor (T), characterized in that the control circuit (CT) comprises an amplifier (AMP) having a first input coupled to the first main electrode of the transistor (T), a second input coupled to the second main electrode of the transistor (T), and an output coupled to the control electrode of the transistor (T), and a reference voltage source (RF1) is coupled in series with at least one of the inputs, i.e. the first and the second input, of the amplifier (AMP). - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a transistor (T) having a control electrode, and a main current path between a first main electrode and a second main electrode of the transistor (T), which main current path is coupled in parallel with the rectifier diode (D); and
Specification