JPH0360342A - Power-supply device - Google Patents

Abstract

PURPOSE:To lower a cost and miniaturize a device by converting a commercial AC power source to DC power output, and by providing the output side of a rectifier circuit for supply the DC power output to an electric equipment, with a secondary battery and a charging circuit. CONSTITUTION:A power-supply device 10 is composed of a line filter 2, a primary rectifying and smoothing section 3, an inverter section 5, a secondary rectifying and smoothing section 7, and the like. Besides stabilizing DC power output, a feedback circuit 11, the switches 20, 21 of a charge and discharge circuit 22, and a secondary battery 25 are connected to the device 10. At the time of a state that the voltage lowering of input power is not found, the DC power is stored in the secondary battery 25 via the switch 20. When the supply capacity of an input power source is short under the working of an electrical equipment, then the DC power stored in the secondary battery 25 is fed to the electric equipment via the switch 21.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a power supply device that converts a commercial AC output into a DC power output and outputs the DC power output.

(Prior Art) Conventionally, as shown in Fig. 3, a commercial AC output 1 inputted from a commercial AC power source is guided to a line filter 2, and this line filter 2 filters out the intrusion noise from the commercial AC input and the inside of the power supply. Removes the feedback noise generated by
- Next, the input is directly rectified and smoothed by a diode and a capacitor, which leads to the rectification and smoothing section 3, resulting in a pulsating output 4, which is then connected to the inverter section 5.
high frequency pulsed alternating current power6 by the switching element.
There is known a power supply device 10 which converts the DC power into a smoothed DC power output 8 using a secondary rectification smoothing section 7 and supplies this DC power output 8 to various electrical devices such as an electronic still camera. ing.

This power supply device 10 is provided with a feedback circuit 11 on the output side of the secondary rectifying and smoothing section 7 so that a DC power output is stably supplied. This feedback circuit 11
has a voltage dividing circuit 14 consisting of a resistor 12 and a resistor 13. The divided voltage of the voltage dividing circuit 14 is used as a control voltage E by a comparator circuit 15 forming a part of the feedback circuit 11.
has been entered. Comparison circuit 15 compares reference voltage 16 and its control voltage E, and outputs the difference to amplifier circuit 17 . The output of this amplifier circuit 17 is input to an on/off control circuit 18. The on/off control circuit 18 is turned on based on the output of the amplifier circuit 17 so that the DC power output becomes smaller when the output is larger than a predetermined value, and becomes larger when the DC power output is smaller than a predetermined value. - Control the inverter section 5 by setting the off time.

(Problem to be Solved by the Invention) However, in this type of power supply device, if the power supply capacity from the power supply device IO is insufficient, the electrical equipment may malfunction, so the power supply capacity is limited to that of the electrical equipment used. This is determined based on the maximum load, and even if the average power consumption is low, the maximum load is high, e.g.
Since electronic still cameras perform intermittent operation that requires instantaneous large currents, when used as a power supply for electronic still cameras, the circuit configuration of the stabilized power supply section of the power supply, such as power transformers, capacitors, transistors, and heat sinks, is required. There are problems in that the electric parts become complicated, the power supply device 10 becomes larger as a whole, the cost increases, and the weight increases, making it inconvenient to carry.

The power supply device according to the present invention was created in view of the above circumstances, and its purpose is to minimize the hindrance to power supply even if it is made compact for low cost and convenient portability. An object of the present invention is to provide a power supply device that prevents this from occurring.

(Means for Solving the Problems) In order to couple the above problems, the power supply device according to the present invention includes a rectifier that converts a commercial AC output into a DC power output and supplies the DC power output to electrical equipment. The present invention is characterized in that the output side of the circuit is provided with a secondary battery that is charged based on the output of the DC power source and for replenishing a decrease in the output of the DC power source, and a charging circuit for charging the secondary battery.

(Function) According to the power supply device according to the present invention, when there is no voltage drop in the DC power output based on the commercial AC power output, the secondary battery receives the DC output based on the commercial AC power output via the charging circuit. Accumulated. When an electrical device is connected and operated, if the power supply's ability to supply DC power output based only on the commercial AC power output becomes insufficient, the DC power stored in the secondary battery Power output is provided to the electrical equipment to make up for the deficit.

(Example) Hereinafter, a power supply device according to the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing a first embodiment of a power supply device according to the present invention, in which the same components as in the conventional example are given the same reference numerals, and the same components as in the conventional example are given the same reference numerals. is almost the same as the conventional example, so
A detailed explanation thereof will be omitted, and different parts will be explained.

In FIG. 1, 20 and 21 are switches, and a charging/discharging circuit 22 is provided between the switch 20 and the switch 21. This charging/discharging circuit 22 also includes a resistor and a diode 24. The resistor 23 functions to charge the secondary battery 25, and the diode 24 functions to discharge the secondary battery 25.

The switch 20 is turned on when a commercial AC output is input to the power supply device 10, and a mechanical switch is used here.
0 is provided on a plug (not shown) and is turned on when the plug is inserted into an outlet (not shown). Note that a transistor switch or the like can also be used as the switch 20.

When this switch 20 is turned on, a part of the DC power output 8 of the secondary current smoothing section 7 is transferred to the secondary battery 25 via the resistor 23.
The secondary battery 25 is charged. As the secondary battery 25, a battery with low internal resistance, for example, a NiCad battery is used.

The switch 21 is turned on when the power supply device 10 is connected to an electric device such as an electronic still camera, and can be configured mechanically like the switch 20. When this switch 21 is turned on, the DC power output stored in the secondary battery 25 is discharged via the diode 24, and the DC power output stored in the secondary battery 25 and the secondary rectifier smoothing section 7 are transferred to the electrical equipment. The output DC power output 8 is supplied to an electric device such as an electronic still camera, and in this case, the secondary battery 2
5 continues to be supplied with the DC current output 8 from the secondary rectifying and smoothing section 7, but if the required load current exceeds the supply capacity of the power supply 10 due to the operation mode of the electrical equipment, the power supply The supply capacity of the device IO cannot cope with the required load current, and the DC power output 8 from the secondary rectifier smoothing section 7
voltage begins to drop. In this case, the DC power output from the secondary battery 25 is supplied to the electrical equipment in order to supplement the shortfall in the DC current output 8 of the power supply device 10.

Therefore, according to this embodiment, the power supply device 10 can be used in electrical equipment, etc., which has a small average load current but a large maximum load current, without increasing the circuit configuration of the power supply device 10.

Note that the switch 20 functions to prevent self-discharge of the secondary battery 25, and instead of using this switch 20, a backflow prevention diode 26 may be provided as shown by the broken line in the figure.

FIG. 2 shows a second embodiment of the power supply device according to the present invention, in which a constant voltage circuit 28 is provided after the rectifier circuit 27,
A charging circuit 2 is connected between the rectifier circuit 27 and the constant voltage circuit 28.
9 are provided in parallel to store the DC power output in the secondary battery 25, while a voltage detection circuit 29' is provided after the constant voltage circuit 28, and the voltage detection circuit 29- outputs the DC power to the electrical equipment. Detecting the decrease in output, switch circuit 3
0 is turned on and off, when the power supply capacity of the DC power output based only on the commercial AC output of the power supply device 10 becomes insufficient, the DC power output from the secondary battery 25 is turned on and off. The configuration is such that the

(Effects of the Invention) Since the power supply device according to the present invention is configured as described above, it has the following effects.

■When the supply capacity of DC power output based only on the commercial AC output of the power supply becomes insufficient, the DC power output stored in the secondary battery is supplied to the electrical equipment to make up for the shortage. Even if we try to make the power supply unit smaller, lower cost, and more portable by simplifying the electrical components that make up the circuit as a stabilized power supply part of the power supply unit, it is necessary to avoid disrupting the power supply as much as possible. It has the effect of being able to

■Also, even in places where commercial AC power cannot be obtained outdoors, this power supply device can be used as an external battery because the DC power output from the secondary battery can be supplied to electrical equipment. be effective.

■Costs can be further reduced if the charging circuit for the secondary battery installed in the power supply device is also used as the charging circuit for the secondary battery installed in the electrical equipment receiving the power supply. be effective.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a power supply device according to the present invention, FIG. 2 is a circuit diagram showing a second embodiment of a power supply device according to the present invention, and FIG. 3 is a circuit diagram of a conventional power supply device. Figure, is. 5... Inverter section (rectifier circuit) 7... Secondary rectifier smoothing section (rectifier circuit) 8... DC power output 10... Power supply device 22... Charge/discharge circuit 25... Secondary battery 29...Charging circuit

Claims (1)

[Claims] (1) The output side of a rectifier circuit that converts commercial AC output into DC power output and supplies the DC power output to electrical equipment is charged based on the DC power output and supplements the drop in the DC power output. 1. A power supply device comprising a secondary battery for charging the secondary battery and a charging circuit for charging the secondary battery.