JPH048135A - Switching power source - Google Patents

Abstract

PURPOSE:To extend the life of a backup power source part and improve power efficiency by outputting first output when the voltage of a main power source part is at a specified value and outputting second output when it is below the specified value. CONSTITUTION:The main power source part 20 and the backup power source part 40 are connected the light emitting element of a main power changeover part 31 and the photodetector of a backup power changeover part 51. The light emitting element gets in the luminous condition when the detection output of a Zener diode 3 is output, and the photodetector is turned on, and the backup power source part 40 stops the power voltage output to the load. When the main power source part 20 does not output a signal, the light emitting element gets in nonluminous condition, and the photodetector is turned off, and the backup power source part 40 outputs power voltage to load. When the main power source part 20 goes wrong, the power supply to load can be done from the backup power source part 40.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention has a main power supply section and a backup power supply section, and in response to a situation such as a failure or a power outage of the main power supply section, the load is removed from the backup power supply section. This invention relates to a switching power supply that can supply power to

(Prior Art) As this type of switching power supply, there is one as shown in FIG.

The switching power supply shown in FIG. 4 has a main power supply section 2 and a backup power supply section 4. The switching power supply shown in FIG.

Both power supply units 2.4 are connected in parallel to each other between the AC power supply 6 and the load 8 via rectifier diodes 10.10, and convert the AC power supply 6 into DC to supply the load 8. It is intended to supply

In this switching power supply, even if the main power supply section 2 operates normally and power is supplied to the load 8 from then on, power is also supplied to the load 8 from the backup power supply section 4. In other words, the backup power supply unit 4 is always in use while the main power supply unit 2 is in use.

Therefore, when the main power supply unit 2 deteriorates in performance with use and eventually reaches the end of its lifespan, the backup power supply unit 4 will also deteriorate in performance and reach the end of its lifespan. When the lifespan of the main power supply section 2 has ended and the power source is switched to the backup power supply section 4, the lifespan of the backup power supply section 4 has also come to an end and it is no longer able to perform its original function. There is a problem.

In addition to this problem, in the switching power supply shown in FIG. Since power is supplied to the load 8 from both power supply units 2.4 at the same time, there is also the problem that the power efficiency of each power supply unit 2.4 becomes extremely poor.

Therefore, in order to eliminate such a problem, as shown in Fig. 5, a relay coil 12 and relay contacts 14a14b that operate in response to the output of this relay coil 12 are provided, and when the main power supply section 2 is in use, By energizing the relay coil 12 and switching the relay contacts 14a and L4b to contact positions opposite to those shown, power from the backup power supply section 4 is prevented from being supplied to the load 8, and the main power supply section 2 is prevented from malfunctioning. In such a case, the relay coil I2 is de-energized and the relay contacts 14a and 14b are switched to the contact positions shown in the figure, so that power can be supplied from the backup power supply section 4 to the load 8 in order to deal with the above-mentioned failure.
There is something small.

(Problem to be solved by the invention) By the way, in the switching power supply shown in FIG.
As shown in the figure, a failure occurs in the main power supply unit 2 at time to, and as a result, the power supply voltage supplied from the main power supply unit 2 to the load 8 decreases, and the voltage applied to the relay coil 12 decreases. is also decreasing. Then, the power supply voltage further decreases, and at time tl, the power supply to the relay coil 12 is substantially stopped, and the relay contacts 14a, 1
Power is supplied to the load 8 from the backup power supply unit 4 only after the switch 4b is switched to the illustrated contact position.

Therefore, in this switching power supply, there is a period in which the power supply voltage supplied to the load 8 drops considerably between times to and tl, and as a result, the load 8 is affected by the drop in power supply voltage during that period. There were inconveniences such as malfunctions.

Therefore, in the present invention, the lifespan of the backup power supply section is extended and the power supply efficiency is improved, and moreover, when the main power supply section fails and the power source is switched to the backup power supply section, it is possible to prevent the load from malfunctioning. The purpose is to ensure that the power supply voltage supplied to the device does not drop.

(Means for Solving the Problems) In order to achieve such an object, the switching power supply of the present invention includes a main power supply section and a backup power supply section. The main power supply section has a main power supply switching section, the main power supply switching section has a power supply voltage detection element and a light emitting element, and the power supply voltage detection element detects the power supply voltage of the main power supply section. and outputs a first detection output when the power supply voltage of the main power supply section is above a predetermined value, and outputs a second detection output when it is less than a predetermined value. The light emitting element is in a first light emitting state in response to a first detection output, and in a second light emitting state in response to a second detection output.

On the other hand, the backup power supply section has a backup power supply switching section, the backup power supply section has a backup power supply switching section, and the backup power supply switching section has a
It has a light receiving element, the light receiving element is arranged at a position to receive light from the light emitting element, and the power of the backup power supply section is turned on in response to the first light emitting state output from the light emitting element. It is characterized in that, while the voltage is brought into an output halt state, the power supply voltage of the backup power supply section is brought into an output state in response to the second light emitting state output.

(Function) In the main power supply section, a first detection output is generated in response to a power supply voltage equal to or higher than a predetermined value in the main power supply section, and a second detection output is outputted in response to a power supply voltage less than a predetermined value.
Output from the power supply voltage detection element. This first or second
In response to the input of the detection output of the light emitting elements, respectively,
The first light emitting state or the second light emitting state is entered.

In the backup power supply unit, the light receiving element in the backup power supply switching unit sets the backup power supply unit to an output stop state in response to the first light emission state, and sets the backup power supply unit to an output state in response to the second light emission state. do.

Therefore, when the main power supply section is operating normally at a power supply voltage higher than a predetermined value, the backup power supply switching section stops supplying power to the load from the backup power supply section, and when the main power supply section is operating normally at a power supply voltage higher than a predetermined value, When a failure occurs in the power supply voltage, the power supply voltage is switched so that the backup power supply section supplies power to the load, and the load is no longer supplied with power from both power supply sections at the same time.

In addition, since power switching is controlled by the light emitting element and the light receiving element, if the main power supply fails, the power supply voltage detection element immediately detects this, and the load is supplied with power supply voltage from the backup power supply. It turns out.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram of a switching power supply according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a main part including the main power switching section of FIG. 1, and FIG. 3 is a circuit diagram of a backup power supply of FIG. FIG. 3 is a circuit diagram of main parts including a switching section.

Referring to FIG. 1, 6 is the AC power supply, and 8.8 is the rectifier diode. The switching power supply of this embodiment includes a main power supply section 2o and a backup power supply section 40 between the AC power supply 6 and the rectifier diodes 8, 8.

The main power supply section 20 basically includes a noise filter 21, a rectifier circuit 22, an inrush current prevention circuit 23, a smoothing circuit 24, a converter transformer 25, a rectifier circuit 26, a smoothing circuit 27, a feedback winding 28, and a control circuit 29. , and a switching element 3o. In general, the AC power supply 6 is rectified by a rectifier circuit 22 via a noise filter 21, smoothed by a smoothing circuit 24 via an inrush current prevention circuit 23, and output to the primary winding of a converter transformer 25. do. Then, the voltage induced on the secondary winding side of the converter transformer 25 is rectified and smoothed by a rectifier circuit 26 and a smoothing circuit 27, and outputted as an output voltage. In order to maintain a constant output voltage, the control circuit 29 controls the switching operation of the switching element 30 based on the induced voltage of the feedback winding 28.

The main power supply unit 20 having such a basic configuration has a second
It has a main power supply switching section 31 whose detailed configuration is shown in the figure. The configuration and operation of the main power supply switching section 31 will be described later.

On the other hand, the backup power supply unit 40 also has the same basic configuration as the main power supply unit 20, including a noise filter 41, a rectifier circuit 42, an inrush current prevention circuit 43, a smoothing circuit 44, a converter transformer 45, a rectifier circuit 46, a smoothing circuit 47, and a feedback circuit. It has a winding 48, a control circuit 49, a switching element 50, and a backup power supply switching section 51, and the operation corresponding to its basic configuration is also similar to that of the main power supply section 20.

The backup power supply unit 40 has a backup power supply switching unit 51 whose detailed configuration is shown in FIG. The configuration and operation of this backup power supply switching section 51 will be described later.

Referring to FIG. 2, the main power supply switching section 31 includes a Zener diode 31a as a power supply voltage detection element, a current limiting resistor 31b, a light emitting element 31C1, and a capacitor 31d.
have.

The Zener diode 31a conducts when the voltage across the inrush current prevention circuit (represented by a resistor) 23 is equal to or higher than a predetermined value, and outputs this to the first detection output and 1. When the value is less than a predetermined value, it becomes non-conductive and is passed to the second
output as the detection output. When the Zener diode 31a is conductive and the first detection output is output, the light emitting element 31c enters the first light emitting state (light emitting state) in response to the first detection output, and the Zener diode 3
When 1a becomes non-conductive and the second detection output is output, the device enters the second light emitting state (non-light emitting state) in response to the second detection output.

Referring to FIG. 3, backup power supply switching section 51 has a light receiving element 51a. This light-receiving element 51a is arranged at a position to receive light from the light-emitting element 31c, and performs an output operation corresponding to each state output of the light-emitting element 31c. That is, it turns on when light emission from the light emitting element 31c is received, and turns off when the light emitting element 31c enters a non-emitting state.

When the light receiving element 51a is on, the switching element 5
0 is off, the backup power supply section 40 is in a state where output of power supply voltage to the load is stopped, and the light receiving element 5
When 1a is turned on, the switching element 50 turns on the control circuit 4.
The backup power supply unit 4 responds to the control output from 9.
0 outputs the power supply voltage to the load.

(Effects of the Invention) As is clear from the above explanation, according to the present invention,
The power supply voltage detection element outputs a first detection output in response to a power supply voltage equal to or higher than a predetermined value in the main power supply section, and a second detection output in response to a power supply voltage lower than a predetermined value, respectively. In response to the input of the first or second detection output, the light emitting element is brought into the first light emitting state or the second light emitting state, respectively, and in the light receiving element of the backup power supply switching part, the main power supply part When the main power supply is operating normally at a power supply voltage higher than the specified value, the backup power supply stops supplying power to the load, and when the main power supply fails at a power supply voltage lower than the specified value, the backup power supply stops supplying power to the load. Since the power supply voltage is switched to supply power, power is no longer supplied to the load from both power supply sections at the same time, and the backup power supply section no longer behaves the same as the main power supply section as in the past. Since the backup power supply section is operated in the event of an abnormality such as a failure of the main power supply section, the life of the backup power supply section can be extended and the power source can be used efficiently.

In addition, since the light receiving element is operated in response to the output of the light emitting element to control switching between the main power supply section and the backup power supply section for the load, if the main power supply section fails, the load is immediately switched from the backup power supply section. The power supply voltage can be supplied, and as a result, even if there is a failure in the main power supply unit, there is no need to supply the load with a reduced power supply voltage, and malfunctions of the load can be prevented.

[Brief explanation of the drawing]

1 to 3 relate to an embodiment of the present invention, and FIG. 1 is an overall schematic circuit diagram of a switching power supply according to the embodiment, and FIG.
The figure shows the main circuit diagram including the main power supply switching section in Figure 1, and the circuit diagram in Figure 3.
The figure is a main part circuit diagram including the bank-up power supply switching section of FIG. 1. Fig. 4 is a circuit diagram of a conventional example, Fig. 5 is a circuit diagram of another conventional example, and Fig. 6 is used to explain the operation of the conventional switching power supply shown in Fig. 5. FIG. 20... Main power supply section, 31... Main power supply switching section,
31a... Zener diode as a power supply voltage detection element, 31c... Light emitting element, 40... Backup power supply section, 51 Backup power supply switching section, 51a... Light receiving element. Figure Figure Figure Figure

Claims (1)

[Claims] (1) It has a main power supply section (20) and a backup power supply section (40), and the main power supply section (20) has a main power supply switching section (31). ) is the power supply voltage detection element (31
a) and a light emitting element (31c), and the power supply voltage detection element (31a) is connected to the main power supply section (20).
When the power supply voltage of the main power supply unit (20) is equal to or higher than a predetermined value, the first detection output is output, and when the power supply voltage of the main power supply unit (20) is lower than the predetermined value, the second detection output is output. The light emitting element (31c) outputs the first detection output in response to the first detection output.
It enters the second light emitting state in response to the light emitting state of the second detection output and the second detection output.
) has a backup power supply switching section (51), and the backup power supply switching section (51) is connected to the light receiving element (51).
a), the light receiving element (51a) is arranged at a position to receive light from the light emitting element (31c), and a first light emitting state output from the light emitting element (31c). In response to this, the power supply voltage of the backup power supply unit (40) is set to the output stop state, and in response to the second light emitting state output, the power supply voltage of the backup power supply unit (40) is set to the output state. Switching power supply with special features.