JPH05333948A - Power unit - Google Patents

Abstract

PURPOSE:To prevent the occurrence of breakage of a power unit despite the malfunction of a selection circuit by connecting a power converting part to a primary power supply only when the selection result of an input circuit is coincident with the input voltage. CONSTITUTION:A power converting part 2 converts the primary power supplied to an input terminal 1 into the electric power after inputting the through a certain selectable input circuit. A selection switch 9 selects one of plural input circuits and leads the power to this input circuit from the terminal 1. A control circuit 7 controls a relay 4 in order to connect the selected input circuit to the terminal 1 when the input voltage detected by an input voltage detecting circuit 6 at the terminal 1 is coincident with the input circuit selected by the switch 9. Thus, it is possible to prevent the breakage of a power unit even if a selection circuit is operated wrong.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device.

[0002]

2. Description of the Related Art For example, nominal power supply voltages of 100 V and 20
There is known a power supply device that rectifies both 0 V commercial AC power supplies (primary power supplies) to obtain a DC output. In such a power supply device, a connection tap for a transformer for 100V and a connection (input) for 200V that can be switched by a changeover switch or the like to a power converter that inputs commercial power and converts the power.
It had a tap and operated the changeover switch to match the voltage of the commercial power supply used before turning on the power switch.

[0003]

However, in the above-described power supply device, the changeover switch is operated by mistake (for example, even though the switch is connected to the 200V power supply,
When the power switch is turned on when the changeover switch is switched to the connection tap for 100V), a voltage of 200V is applied to the power conversion unit that converts AC into DC through the connection tap for 100V, and as a result, There is a risk that the rectifying diode, the smoothing capacitor, and the like that compose the power conversion unit will be damaged due to an excessive voltage.

Therefore, an object of the present invention is to provide a power supply device that solves the above problems.

[0005]

In order to achieve the above object, the present invention provides a power for inputting a primary power supply supplied to an input terminal through any of a plurality of selectable input circuits, converting the power, and outputting the converted power. A conversion unit, and a selection unit for selecting any one of the plurality of input circuits and guiding electric power from the input terminal,
Connection means for connecting the input terminal and the selected input circuit, input voltage detection means for detecting an input voltage at the input terminal, input circuit selected by the selection means, and detection by the input voltage detection means And a means for controlling the connecting means so that the selected input circuit is connected to the input terminal when the input voltage matches the input voltage.

[0006]

According to the present invention, the power converter is not connected to the primary power source unless the selection result of the input circuit and the input voltage match. In the case of non-conformity, the operator is notified by a warning display function such as a warning lamp and a buzzer.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which 1 is an input terminal to which a commercial power source (100 V or 200 V) is supplied, 2 is a rectified input AC, and DC is output to an output terminal 3. An output power conversion unit, which is a selection unit (described later)
It has respective input circuits for 100V and 200V selectable by. Reference numeral 4 is a relay as a connecting means, which connects the input end 1 and the selected input circuit of the power converter 2 by the normally open contact thereof. Reference numeral 5 denotes a wide input range type (here, 100V to 200V) small power auxiliary power source, which includes a relay 4, an input voltage detection circuit 6 described later, and a control circuit 7.
And a desired DC low voltage is supplied to the relay as the selection means, but a small output of, for example, several W may be obtained.

A power switch 8 is provided between the input terminal 1 and the input of the auxiliary power supply 5. The input voltage detection circuit 6 rectifies the input voltage from the input terminal 1 obtained via the power switch 8 by the diode 6A,
Smoothed by B and capacitor 6C, and reference voltage 6E (for example, 170V here) by comparator 6D.
In comparison, when the voltage is higher than the reference voltage (here, the commercial AC power supply voltage at the input terminal 1 is 200V), the comparator 6D is turned on and outputs a high voltage (200V) detection signal (for example, 5V). Reference numeral 9 is a selection switch for outputting an input voltage selection signal. The DC voltage (5 V) from the auxiliary power supply 5 is applied to the a side, the b side is open, and the input voltage is selected only when the a side is selected. The DC voltage (5V) is output as a signal. Here, a side is 10
0V selection and b side are 200V selection.

2 (a) and 2 (b) show another specific example of the power conversion section 2. In FIG. 2 (a), 21 is a transformer whose primary winding is a two-winding type, and 22 is a transformer 21. A secondary winding, that is, a relay for switching the input taps,
A DC voltage (5V) is supplied to the coil as an input voltage selection signal from the selection switch 9 that selects 100V,
When the contact drive current flows, the contacts are switched so that the primary windings are connected in parallel to the commercial power source input (state shown in the drawing), and when the selection switch 9 selects 200V,
The voltage from the selection switch 9 is not supplied to the coil,
When the current does not flow, the contacts are switched so that the primary windings are connected in series, and the input taps are switched as described above. Reference numeral 23 is a bridge rectifier connected to the secondary winding of the transformer 21, and its rectified output is smoothed by the capacitor 24, and the transistor 25 and the error amplifier 2 are provided.
6. The voltage of the reference power supply 27 is stabilized by the reference power supply 27 and is output.

In FIG. 2 (b), 28 is a diode bridge composed of four rectifying diodes forming an input circuit. Two input terminals are connected to a commercial power source input terminal and two output terminals are two. It is connected to both ends of the series circuit of the smoothing capacitor 29 and the input of the DC-DC converter 30. Reference numeral 31 is a relay that operates in the same manner as the relay for switching the input taps in FIG. 2A, and a DC voltage (5V) is supplied to the coil as an input voltage selection signal from the selection switch 9 that selects 100V. Then, the contact drive current flows and the diode bridge 2
One input end of 8 and the intermediate point of two capacitors 29 are connected by a contact, and the contact is switched so that a rectified voltage that is twice the power supply input voltage (100 V) is obtained at the output end of the diode bridge 28 (shown in the figure). Status), selection switch 9
When 200V is selected, the coil is not supplied with the voltage from the selection switch 9 and no current flows, so that the contact opens and a rectified voltage equal to the power input voltage (200V) is output to the output end of the diode bridge 28. The contact is switched so as to obtain, and the input circuit is switched as described above. In addition, the relay 2 for switching the input circuit
Instead of 2, 31, a so-called electronic switch composed of a semiconductor element or the like can be used.

FIG. 3 is a block diagram of the control circuit 7.
Reference numeral 0 is a CPU, 11 is a ROM storing a control program and the like as described later (FIG. 4), and 12 is a working R of the CPU 10.
AM and 13 are indicators (warning display function) for displaying power input voltage, errors indicating erroneous operation of the selection switch, and 14 is a key matrix (switch) for designating output voltage, current, and the like. ..

Reference numeral 15 is an input port for inputting a signal from the input voltage detection circuit 6 and a signal from the selection switch 9. Reference numeral 16 denotes an output port, which outputs a drive signal for connecting the input end 1 and a selected input circuit of the power conversion unit 2 to the coil of the relay 4 by closing its normally open contact.

FIG. 4 shows the operation procedure of the CPU 10 of the control circuit 7. After the power switch 8 is turned on, first, in S1, the signal from the selection switch 9 is read (as an input voltage selection signal, a DC voltage is selected when 200V is selected). (5V) is 100V
When selected, 0V is input to each input port 15), S
2 reads the signal from the input voltage detection circuit 6 (when the power supply input voltage is 200V, the high voltage detection signal (5V) is
When the voltage is 100V, 0V is input to the input port 15), and it is determined in S3 whether the two signals input to the input port 15 match. If they match, the voltage selected by the selection switch 9 (that is, the input circuit of the power conversion unit 2 also corresponds to the voltage selected by the switch 9).
And the power supply input voltage supplied to the input terminal 1 match, the drive signal is output to the relay 4 in S4, and the normally open contact is closed to select the selected input of the input terminal 1 and the power conversion unit 2. Connect to the circuit and return. If they do not match in S3, the drive signal is not output to the relay 4 in S5 (therefore, the power input is not supplied to the power conversion unit 2), an error display (warning display) is displayed on the display 13, and the process returns. ..

[0015]

As described above, according to the present invention, even if the selecting means for selecting the input circuit of the power converter is erroneously operated,
No power input is supplied to the power converter, and there is no risk of damage or the like.

[Brief description of drawings]

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

FIG. 2A and FIG. 2B are diagrams showing other specific examples of the power conversion unit.

FIG. 3 is a block diagram of a control circuit.

FIG. 4 is a flowchart showing the operation of the embodiment.

[Explanation of symbols]

 1 Input Terminal 2 Power Converter 4 Relay 5 Wide Input Range Type Auxiliary Power Supply 6 Input Voltage Detection Circuit 7 Control Circuit 8 Power Switch 9 Selection Switch

Claims (2)

[Claims] 1. A power conversion unit for inputting a primary power supply supplied to an input terminal through any of a plurality of input circuits capable of being selected, converting power, and outputting the power, and any one of the plurality of input circuits. Selecting means for selecting and introducing electric power from the input terminal; connecting means for connecting the input terminal and the selected input circuit; and input voltage detecting means for detecting an input voltage at the input terminal, A means for controlling the connecting means so that the selected input circuit is connected to the input terminal when the input circuit selected by the selecting means matches the input voltage detected by the input voltage detecting means. A power supply device comprising: 2. The power supply device according to claim 1, which has a function of displaying a warning when the input circuit selected by the selection means and the input voltage detected by the input voltage detection means do not match.