JPH01107654A - Fet rectification - Google Patents

Abstract

PURPOSE:To enhance efficiency, by driving a rectifying FET via a pulse transformer with the output of a controlling circuit. CONSTITUTION:A FET rectifying system is composed of a DC power source 1, a transformer 2, a switch element 3 switched in a specified period and a specified conduction width variable switches 4-5 series-connected to the secondary side of the transformer 2 and suppressing partial output fed to the load side in the conduction period of the primary side switch 3, and a controlling circuit 6 for driving the gate of the switch element 3. The controlling circuit 6 is composed to drive the variable switches 4-5 via a pulse transformer 7, and the clock of the circuit 6 is synchronized with clock signal 8. Then, by the controlling circuit 6, output voltage and previously set reference voltage are compared with each other, and by regulating the clock signal, the output voltage Vo is regulated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rectification method of a switching regulator.
In particular, it relates to the FET rectification system.

[Conventional technology]

Conventionally, the rectification method of a switching regulator is a diode rectification method.

[Problem that the invention seeks to solve]

The conventional diode rectification method described above has a problem in that even when the output current is small, a loss occurs depending on the forward voltage drop of the diode.

[Means for solving problems]

The FET rectification method of the present invention includes a power supply circuit that induces a rectangular wave on the primary side of the transformer via a switching element that is opened and closed at a predetermined period and with a predetermined conduction width, and a power supply circuit that is connected in series to the secondary side of the transformer. A variable switch that blocks part of the output supplied to the load side during the conduction period of the connected primary side switching element, a control circuit that drives this variable switch via a pulse transformer, and a control circuit that rectifies and rectifies the output of the variable switch. It includes a rectifying and smoothing circuit for smoothing.

[Effect]

In the present invention, the rectifying FIT is driven by the output of the control circuit via a pulse transformer.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, 1 is a DC power supply, 2 is a transformer, and 3 is a switch element that opens and closes at a predetermined period and with a predetermined conduction width;
This constitutes a power supply circuit that induces a rectangular wave on the primary side of the transformer 2 via the transformer 2.

4.5 is a switch element, and this switch element 4.5 is connected in series to the secondary side of the transformer 2 and is connected to the primary side switch element 3.
A variable switch is configured to block part of the output supplied to the load side during the conduction period of the switch.

A control circuit 6 compares the output voltage with a preset reference voltage and generates a clock signal 8 to drive the gate of the switch element 3. This control circuit 6 drives the variable switch via the pulse transformer T. It is configured as follows.

The clock of this control circuit 6 is synchronized with the clock signal 8.

9 is a flywheel diode, 10 is a choke coil, and 11 is a capacitor, which constitute a rectifying and smoothing circuit that rectifies and smoothes the output of the variable switch. 12
m, 12b is an output terminal from which an output is obtained.

Figure 2 is a waveform diagram of each part used to explain the operation of Figure 1.
A) shows the waveform of the voltage VS across the secondary side of transformer 2. Ah! (b) is the secondary side voltage of the pulse transformer 1, that is, the gate voltage vse of the switching element 4.5.
(C) shows the waveform of the voltage vL after rectification. Note that vO indicates the output voltage, and G is the ground potential □
, h) shows the on period of the switch elements 4 and 50, and (b) shows the off period of the switch element 4.5.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2.

First, the switching element 3 is opened and closed at a predetermined period and with a predetermined conduction width to induce a rectangular wave as shown in FIG. The switching elements 4 and 5 are made conductive by the clock signal from the circuit 6 via the pulse transformer 7 (see FIG. 2(b)). Next, the control circuit 6 compares the output voltage with a preset reference voltage and adjusts the clock signal.
t-adjust (see Figure 2(c)).

〔Effect of the invention〕

As explained above, the present invention allows a FET rectifier circuit to be easily configured by driving a rectifying FET with the output of a control circuit via a pulse transformer, and has a high performance compared to the conventional diode rectification method. The efficient rectifier circuit can beautify the skin and has stone effects.

[Brief explanation of the drawing]

FIG. 4 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 4 is a waveform diagram of each part for explaining the operation of the figure. 1...DC power supply, 2 fists...transformer, 3-5...
・Switch element, 6...Control circuit, 7...Pulse transformer, 9...Flywheel diode, 1
0...Choke coil, 11.@--Capacitor.

Claims (1)

[Claims] A power supply circuit that induces a rectangular wave on the primary side of the transformer through a switch element that is opened and closed at a predetermined period and with a predetermined conduction width, and a power supply circuit that is connected in series to the secondary side of the transformer and conducts the primary side switch element. A variable switch that blocks part of the output supplied to the load during a period, a control circuit that drives this variable switch via a pulse transformer, and a rectifying and smoothing circuit that rectifies and smoothes the output of the variable switch. FET rectification system featuring