JPH05227653A - AC adapter power supply voltage recognition switching device - Google Patents

Abstract

(57) [Abstract] [Purpose] Regarding a device for recognizing the power supply voltage of the DC output from the AC adapter to the terminal device, whether the voltage is suitable for the terminal device by detecting the voltage value of the terminal DC jack. The purpose is to determine and supply power. [Structure] The AC plug 3 of the AC adapter 1 is inserted into the AC socket, the DC plug 4 is inserted into the DC jack 5 of the telephone terminal 2, and the DC output from the AC adapter is recognized as the power supply voltage to the telephone terminal 2. In the device that switches by
A discriminating circuit 7 for discriminating the power supply voltage is provided in the device, and the discriminating circuit 7 comprises a polarity discriminating circuit section 8, a voltage measuring circuit section 10 and a power supply inserting circuit section 9. The polarity is rectified so that it matches the telephone terminal 2, and the voltage measuring circuit section 10 measures whether or not the voltage matches the rated load. It is configured to be supplied to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to DC from an AC adapter.
The present invention relates to a device for recognizing a power supply voltage to an output terminal device. With the downsizing of telephone terminals, it becomes difficult to have a built-in power supply, that is, to have a cord compatible with an AC 100V outlet, so that AC 100V can be converted to DC by an AC adapter, and DC can be supplied from the DC plug of the AC adapter. Has become.

FIG. 5 shows an example of the circuit configuration of an AC adapter.
The AC adapter inputs AC 100V from an AC outlet, outputs a specified DC voltage from a DC plug and supplies it to the DC jack of the terminal side device, and uses it as a DC power source of the terminal side device. The AC adapter is composed of a conversion transformer, a rectifying circuit and a fuse, and outputs a necessary voltage by changing the secondary winding side of the conversion transformer. The circuit of FIG. 5 is an example, and there are one that outputs a plurality of DC voltages and one that uses a transistor as a switching element.

The DC output voltage of these AC adapters differs depending on the terminal equipment to be connected, and the type of AC adapter is selected according to the terminal equipment to be used. Therefore, the type of the AC adapter may be mistakenly selected or the polarity of the DC plug may be reversed, which may damage the terminal-side device.

[0004]

2. Description of the Related Art FIG. 6 shows an example of the connection configuration between an AC adapter and a terminal device. In the figure, 21 is an AC adapter, 22 is a telephone terminal, 23 is an AC plug, 24 is a DC plug, and 25 is a DC.
Jack and 26 are main units. AC adapter 21
AC plug 23 of is inserted in the AC 100V outlet,
The DC plug 24 of the C adapter 21 is inserted into the DC jack 25 of the telephone terminal 22. The main unit 26 can be operated by the DC power supply from the AC adapter 21.

As shown in the figure, the DC plug 24 and the DC jack 25 form a cylindrical shape, and either the + terminal or the-terminal is set, and the main unit 26 to be used is used.
Corresponding to, it is used as + DC power supply or-DC power supply. In addition, the standard of the AC adapter 21 has been decided according to the operating voltage and capacity of the main unit 26.
The DC plug 24 must be inserted into the DC jack 25 after confirming the rating of the adapter 21.

[0006]

As described above, there are some shapes of the DC jack of the DC output of the AC adapter, but the same shape may have different voltages or different polarities. Therefore, the maintenance person must check the rating of the AC adapter in advance and use it, and if the rating of the AC adapter differs from that of the device on the terminal side, the device on the terminal side may be damaged.

In view of the above, an object of the present invention is to detect the voltage value of the DC jack on the terminal side, automatically determine whether or not the voltage is suitable for the device, and to supply power to the device on the terminal side.

[0008]

FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 1 is an AC adapter, 2 is a telephone terminal, 3 is an AC plug, 4 is a DC plug, 5 is a DC jack, 6 is a main unit, 7 is a discrimination circuit, 8 is a polarity discrimination circuit section, and 9 is a power supply insertion circuit. Reference numeral 10 denotes a voltage measuring circuit portion. The AC plug 3 of the AC adapter 1 is inserted into the AC 100V socket, and the DC plug 4 is inserted into the DC jack 5 of the telephone terminal 2.

The discriminating circuit 7 comprises a polarity discriminating circuit portion 8, a voltage measuring circuit portion 10 and a power supply inserting circuit portion 9, and the polarity discriminating circuit portion 8 rectifies the polarity of the input DC voltage so as to match the telephone terminal 2. The voltage measuring circuit unit 10 measures whether or not the voltage is suitable for the rated load, and if the voltage is suitable, the power supply inserting circuit unit 9 supplies DC power to the main unit 6.

[0010]

2 is a processing flowchart of the power supply voltage recognition switching device of the present invention. (1) Insert the DC plug 4 of the AC adapter 1 into the DC jack 5. (2) The voltage which is rectified by the polarity determining circuit unit 8 and which has a suitable polarity is supplied to the voltage measuring circuit unit 10. (3) Check the input DC voltage with the comparator of the voltage measurement circuit section 10. (4) If it is not within the error range of the reference voltage, an alarm is displayed. (5) If it is within the error range of the reference voltage, insert the actual load in the discrimination circuit. (6) With the actual load inserted, check the DC voltage again with the comparator. (7) If it is not within the error range of the reference voltage, an alarm is displayed and
If it is within the error range of the reference voltage, the voltage rectified by the power supply insertion circuit section 9 and having a suitable polarity is inserted into the main unit 6, and the main unit 6 starts operating.

[0011]

FIG. 3 shows an embodiment of a circuit configuration diagram of a power supply voltage recognition switching device of the present invention. In the figure, 11 is a DC jack, 12 is a full-wave rectifier, 13 is an upper limit comparator, 14 is a lower limit comparator, 15 is a rated load, 16 is a relay A, 17 is a relay B, 18 is a microprocessor, 19 is a main unit. , 20 are power supply voltage recognition switching devices. The full-wave rectifier 12 constitutes a polarity discriminating circuit section, and the upper limit comparator 13 and the lower limit comparator 14 check whether or not the measured voltage is within the upper and lower limit voltage range.

The relay A16 checks whether the measured voltage is within the upper and lower limits with the rated load 15 inserted, and the measured voltage is within the upper and lower limits with the rated load 15 inserted. If so, the relay B17 operates after the relay A16 is restored. The main unit 19 is connected to the full-wave rectifier 12 by the operation of the relay B17 and is supplied with a DC voltage having a polarity matching the reference. The control of these relays and measuring circuits is controlled by the microprocessor 18.

FIG. 4 shows an embodiment of a control flowchart of the power supply voltage recognition switching device. The control operation will be described with reference to FIGS. 3 and 4. (11) An AC adapter is inserted into the DC jack 11, and a DC voltage is supplied to the voltage measurement circuit via the full wave rectifier 12. (12) The upper limit comparator 13 and the lower limit comparator 14 check whether or not the input voltage is within the upper and lower limits of the reference voltage. (13) If the input voltage is not within the upper and lower limit ranges as a result of the check in (12) above, an alarm is sent as an abnormal voltage and displayed on the LED. (14) If the input voltage is within the upper and lower limits as a result of the check in (12) above, activate relay A16 to activate the rated load.
Insert 15 in parallel with the input power supply. (15) With the rated load 15 inserted in the input power supply, the voltage measurement check according to (12) above is performed. If it is not within the range, an alarm is sent out as an abnormal voltage and displayed on the LED. (16) If the voltage is within the range, it is judged as a normal voltage and the relay A16 is released. (17) Operate relay B17 after releasing relay A16. (18) The main unit 19 is connected to the full-wave rectifier 12 by the operation of the relay B17, and the DC voltage connected to the DC jack 11 is determined to be the DC voltage that is the reference.
Supplied to 19.

The internal power supply V of the power supply voltage recognition switching device may be supplied by a battery, or may be switched to the power supply from the main unit after the power supply to the main unit.
If the DC power supply is 24V, the internal power supply can be set to 5V and the upper and lower limits can be set to ± 20%.

[0015]

According to the present invention, in the case where the terminal device and the AC adapter do not correspond to each other, the device is protected even if the AC adapter of a different standard is mistakenly inserted, so that the device is not damaged. .. Also, it is possible to avoid unstable operation when an AC adapter having a voltage lower than the specified voltage is inserted.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention.

FIG. 2 is a processing flowchart of the present invention.

FIG. 3 is a circuit configuration diagram of an embodiment.

FIG. 4 is a control flowchart of the embodiment.

FIG. 5 is a circuit configuration example of an AC adapter.

FIG. 6 is a connection configuration diagram of a conventional example.

[Explanation of symbols]

 1,21 AC adapter 2,22 Telephone terminal 3,23 AC plug 4,24 DC plug 5,11,25 DC jack 6,19, 26 Main unit 7 Discrimination circuit 8 Polarity discrimination circuit section 9 Power insertion circuit section 10 Voltage measurement Circuit part 12 Full-wave rectifier 13 Upper limit comparator 14 Lower limit comparator 15 Rated load 16 Relay A 17 Relay B 18 Microprocessor 20 Power supply voltage recognition switching device

Claims (1)

[Claims] 1. An AC plug (3) of an AC adapter (1)
To the AC socket, insert the DC plug (4) into the DC jack (5) of the telephone terminal (2), and recognize the DC output from the AC adapter (1) as the power supply voltage to the telephone terminal (2). In the switching device, a discriminating circuit (7) for discriminating the supply voltage is provided in the device, and the discriminating circuit (7) includes a polarity discriminating circuit section (8), a voltage measuring circuit section (10), and a power supply inserting circuit section (7). 9), and the polarity determination circuit section (8) rectifies the polarity of the input DC voltage so that it matches the telephone terminal (2), and the voltage measurement circuit section (10).
It is measured whether the voltage is suitable for the rated load, and if it is, the power supply insertion circuit section (9) supplies the DC power from the polarity determination circuit section (8) to the main unit (6).
AC adapter power supply voltage recognition switching device characterized by supplying to.