JPS5914825Y2 - Switching regulator device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switching regulator device, and in particular improves an auxiliary power source for driving a control circuit in a switching regulator device.

Generally, in switching regulator devices, AC
If the control circuit does not start up first when the input is turned on, the converter may become unstable and the circuit may be short-circuited and destroyed.

In order to limit the rush current to the converter, a method is generally used to insert a temporary resistor into the input circuit.

If current constantly flows through this input resistor, power consumption will increase and heat generation will be large, which will have a negative impact on the device. Therefore, an AC relay is inserted to prevent inrush current, and the AC relay is normally open in parallel with the input resistor. It has a configuration in which the contacts are connected.

The present invention was developed by focusing on this point, and includes an ACIJ tray for inrush current prevention and a normally closed contact, and through this normally closed contact, the DC output from the main power supply section is controlled for a short period of time from when the AC input is turned on. The present invention provides a switching regulator device that supplies power to a circuit and ensures that a control circuit starts up before a converter.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic circuit diagram showing an embodiment of a switching regulator device according to the present invention, in which AC power 10 is supplied to a diode bridge 12 of a main power supply section through a power switch 11 and a resistor R1 in series.

The full-wave rectified output from the diode bridge 12 is smoothed by a smoothing capacitor 13 that constitutes a main power supply section, and is applied to a DD converter 14.

This DD converter 14 is of a type that uses an output transformer, and the output from the converter 14 is taken out via a converter transformer, converted into a stable DC output, and supplied to an output terminal 15.

16 is an AC relay for inrush current prevention connected between the input terminals of the diode bridge 12, and its normally open contact 16S1
is connected in parallel with the resistor R1, and after the ACC operation, the resistor R1 is short-circuited to reduce power consumption and at the same time prevent the adverse effects of heat generation.

Reference numeral 17 denotes a control circuit consisting of a switching fundamental frequency oscillation circuit, a reference voltage generation circuit, a comparison amplification circuit, a drive circuit, etc. The control circuit 17 generates direct current from the converter transformer of the converter 14 via a diode 18 and a smoothing capacitor 19 that constitute an auxiliary power supply section. An input is applied, and a DC output is supplied from the output side of the device for comparison.

In the present invention, in the switching regulator device having such a configuration, a normally closed contact 16S2 is further added to the AC relay 16 for preventing rush current, and this normally closed contact 16S2 is added to the AC relay 16 for preventing rush current.
2 is inserted between the output of the main power supply section and the input of the control circuit 17 via a resistor R2 in series.

Next, the operation of the device of the present invention having such a configuration will be explained with reference to FIG.

The AC relay 16 does not operate when the power switch 11 is turned on and for a short time thereafter because of the voltage drop across the resistor R1.

That is, when the AC input is turned on as shown in FIG. 2A, the voltage v16 applied to the AC relay 16 is the second
When V16 rises to about 80V as shown in Figure B, the relay 16 operates for the first time as shown in Figure 2C, closing its normally open contact 16S1 and closing its normally closed contact 1
6S2 is opened, that is, the ACC loop 16 does not operate for a time T from when the AC input is turned on.

On the other hand, when the power switch 11 is turned on, the DC output voltage e1 is supplied from the main power supply section to the input of the control circuit 17 via the normally closed contact 16S2 and the resistor R2.
7 stands up.

During the time T1, which is shorter than the hour after the AC input is turned on, the voltage supplied to the converter 14 from the main power supply is too low to operate the converter 14, and therefore only the control circuit 17 operates.

After time T1 has elapsed, the output voltage of the main power supply section reaches a level at which converter 14 can be operated, and converter 14 starts operating.

At this point, the DC voltage e2 supplied to the control circuit 17 from the converter transformer via the diode 18 becomes higher than 6, so that e2 is supplied to the control circuit 17 instead of el.

Thus, the voltage v17 supplied to the control circuit 17 changes as shown in the second diagram, and reaches a predetermined constant voltage before time T has elapsed.

After the time T has elapsed, the relay 16 operates to short-circuit the resistor R1 and at the same time cut off the initial rise drive circuit for the control circuit 17 via the resistor R2, shifting to a normal operating mode.

As shown in FIG. 5E, the DC output voltage from the device output terminal 15 reaches a constant output immediately before the relay 16 operates, providing a stabilized DC output to the load.

As described above, according to the present invention, since the control circuit 17 starts up first and then the converter 14 starts up when the power is turned on, there is no possibility that the converter 14 becomes unstable and the circuit becomes short-circuited.

Further, since one normally closed contact is simply added to the AC relay 16, the configuration can be made inexpensively and easily.

Furthermore, since the resistor R2 is separated after the converter 14 starts up, for example, when the load is short-circuited, the secondary side of the converter transformer is grounded and the resistor R2 is separated.
2. This avoids the drawback that a large current flows through the circuit, which increases heat generation and becomes dangerous.

That is, when the load is short-circuited, the control circuit and the converter are in a stopped state.

Therefore, it has remarkable effects when used in various electronic devices.

It should be noted that the above embodiment is merely an example of the present invention, and therefore, it goes without saying that various changes can be made as necessary.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of a switching regulator device according to the present invention, and FIG. 2 is various waveform diagrams for explaining the operation of the device shown in FIG. 1. In the figure, 10 is an AC input, 11 is a power switch, 12 is a diode bridge, 14 is a converter, 16 is an AC relay, and 17 is a control circuit.

Claims (1)

[Scope of utility model registration request] A main power supply unit consisting of a rectifier circuit and a smoothing circuit that converts AC input to DC, a converter that stabilizes DC power from the power supply unit, and a control circuit that controls the converter;
In a switching regulator device comprising an ACC loop connected between input terminals of the main power supply unit and having a normally open contact that closes a resistor that limits AC input to the main power supply unit, the relay is provided with a normally closed contact. , the normally closed contact and the resistor are connected in series to supply the DC output of the main power source to the control circuit, and the main Supplying power from a power supply unit to the control circuit to start up the control circuit before the converter starts up, so that the normally open contact is closed and the normally closed contact is opened by the operation of the relay. A switching regulator device comprising: