JP2002051453A - Power supply control device and power supply control method for electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut off a main power supply without causing breakdown of an apparatus, when an overvoltage higher than a power supply rating is applied, etc. SOLUTION: If an AC power supply with a voltage higher than a rating is mistakenly connected to an input terminal 1 or high voltage of a lightning surge is inputted, Zener diodes 3 and 8 are closed, a transistor Tr1 is turned on, a closed transistor Tr2 for a relay RL is opened, the relay RL is turned off, an overvoltage protective switch 4 is opened, and further, a voltage is applied to a comparator 5, so that an H-level signal is outputted. When a control microcomputer 9 receives the H-level signal from the comparator, its terminals t1 and t2 go into H levels. If the terminal t1 of the control microcomputer 9 goes to H level, a power supply latch circuit 7 with a thyristor function is turned on, the off-states of the relay RL and the switch 4 are held and the off-state of the power supply is held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control device and a power supply control method capable of turning off a power supply of an electronic device without damaging the device when an overvoltage is applied to the electronic device.

[0002]

2. Description of the Related Art The voltage of a commercial power supply varies considerably from country to country, and in Latin America, some countries differ from one country to another. For example, Japan is 100V, while Europe is 2V.
20V and Korea are 220V. In Japan, 200 volt power supplies for air conditioners are
There is an example in which it is installed in combination with a volt power supply. Also,
In a country where the power situation is poor, the power supply voltage fluctuates considerably. Therefore, the power supply voltage of an electronic device may be adjusted by a voltage regulator or the like before use.

In many cases, small portable electric devices (such as hair dryers and electric razors) are provided with various measures to cope with erroneous connection due to the difference in power supply voltage.

[0004]

On the other hand, large devices such as televisions and projectors may be plugged into a 200 volt outlet by mistake or if the AC power supply and voltage are set incorrectly. In order to protect the internal components of the device, a fuse is provided inside the device to cut off the fuse, and when an overvoltage is applied, the internal fuse is cut. FIG. 3 shows an example of an overvoltage protection circuit of an electronic device. A fuse 1 is connected to the input section on the AC power supply 1 side.
0, protective components such as a line filter 11 and a varistor 12, a power switch 15 controlled by a remote controller, and a transformer T1 for obtaining a voltage for driving an electronic device. In a power supply circuit of such an electronic device, when a surge overvoltage exceeding the power supply rating is applied, the varistor and the like are short-circuited, so that the fuse 10 is blown and the power supply circuit is opened to protect the overvoltage. However, in the worst case, there has been a problem that the power supply of the electronic device is damaged. Even if the fuse 10 is only blown by applying a surge overvoltage higher than the power supply rating, the internal components are protected, but in the case of a large electronic device in recent years, the fuse 10 is attached to a circuit board inside the electronic device. Since it is often installed, it is difficult to work such as disassembling the housing of the electronic device to replace the fuse.In some cases, it is necessary to replace the entire circuit board and ask the manufacturer for service. I have to.

[0005] An object of the present invention is to solve these problems, when an overvoltage is applied to a power supply, the level of a rectified output is detected, and when it is determined that the voltage is overvoltage, the main power supply is turned off.
In addition to the display, the main power is turned off by latching so that the main power is not released by the remote control or key operation. Even if an overvoltage is applied to the device due to connection or the like, the device is protected.

[0006]

According to a first aspect of the present invention, there is provided a DC conversion means for supplying a DC voltage obtained by converting an AC power supply, and a level of the DC voltage obtained by the DC conversion means. Voltage detecting means for detecting, control information forming means for forming control information according to an operation state of an operation button, and a main load circuit driven by the AC power supply when the detected voltage is higher than a predetermined voltage So that the main load circuit driven by the AC power supply continues the non-operating state even when an ON instruction is given based on the control information from the control information forming means. And a control means for controlling the power supply of the electronic device.

The invention according to claim 2 is connected to an AC power supply,
In a power supply device that obtains a desired DC voltage, a voltage detection unit that rectifies the AC power and detects a level of the DC voltage obtained by smoothing, and forms control information according to an operation state of an operation button. Control information forming means, control means for controlling the main load circuit driven by the AC power supply to be in a non-operation state when the detected voltage is higher than a predetermined voltage, and after the non-operation state, And a latch means for latching a signal output from the control means and keeping a non-operating state in a main load circuit driven by an AC power supply.

According to a third aspect of the present invention, there is provided a DC conversion means for supplying a DC voltage obtained by converting an AC power supply, and a voltage detection means for detecting a level of the DC voltage obtained by the DC conversion means. And receiving means for receiving a remote control signal sent from the remote control transmitter, and forming control information according to the received remote control signal, and when the detected voltage is higher than a predetermined voltage, A main load circuit driven by the AC power supply is controlled so that the main load circuit driven by the AC power supply is in an inactive state, and is also driven by the AC power supply when an ON instruction is given based on a remote control signal from the receiving means. And control means for controlling the circuit to maintain the non-operating state.
A power supply control device for an electronic device, further comprising a display unit for displaying that a main load circuit driven by the AC power supply is in an inactive state.

According to a fifth aspect of the present invention, there is provided a voltage detecting step for detecting a level of a DC voltage obtained from an AC power supply, a step of forming control information according to an operation state of an operation button, Is higher than a predetermined voltage,
The main load circuit driven by the AC power supply is controlled so that the main load circuit driven by the AC power supply is in a non-operating state. Controlling the power supply of the electronic device.

According to a sixth aspect of the present invention, there is provided a voltage detecting step for detecting a level of a DC voltage obtained by converting an AC power supply, a step of forming a control signal corresponding to a received remote control signal, Controlling the main load circuit driven by the AC power supply to be in an inactive state when the detected voltage is higher than a predetermined voltage; and turning on an instruction based on the received remote control signal. Controlling the main load circuit driven by the AC power supply to remain in the non-operating state even when the operation is performed.

The invention according to claim 7 is a power supply control method for an electronic device, characterized by indicating that the main load circuit driven by the AC power supply is in an inactive state.

[0012]

FIG. 1 shows an example of an embodiment of the present invention.
It will be described based on. FIG. 1 is a block diagram illustrating a configuration of a power supply control device including an overvoltage protection circuit according to the present invention.
The same members as those in FIG. 3 are denoted by the same reference numerals.

In FIG. 1, 1 is an input terminal of an AC power supply,
Reference numeral 2 denotes a standby power supply that rectifies and smoothes the AC power output from the insulating transformer T2 and supplies it to the standby circuit as DC power. Reference numerals 3 and 8 denote a Zener diode that conducts when a predetermined voltage or more is reached. 4 denotes an overvoltage protection switch that is configured so that the relay RL is driven and cut off when an overvoltage is applied; For example, a comparator that outputs an H level signal, 6
Is a display circuit for displaying when an overvoltage is applied, 7 is a latch circuit, 9 is a control microcomputer having a light receiving section 91 for receiving a signal from a remote controller 92, 12 is a protection circuit for a secondary-side electronic circuit, and 13 is a control circuit. A three-terminal regulator for supplying power to the microcomputer 9, an output terminal 14 of the control microcomputer 9 for controlling a normal power switch 15, and a driving switching power supply 16 for generating a normal voltage for driving the electronic device. . The control microcomputer 9 has a terminal t1 for supplying a signal to the power supply latch circuit 7, a terminal t2 for supplying a signal to the display circuit 6, a terminal t3 for supplying a signal from the comparator 5 to the control microcomputer 9, and a power switch 15. A terminal t4 for supplying a signal, a terminal t5 for supplying a signal from the remote control light receiving section 91 to the control microcomputer 9, and a terminal t6 for supplying power from the standby power supply 2 to the control microcomputer 9 are provided. Tr1, Tr2 and Tr3 indicate transistors, respectively.

Hereinafter, the operation of the power supply control device of the present embodiment having the overvoltage protection circuit of FIG. 1 will be described.

When a user of the electronic device connects the input terminal 1 of the AC power supply to an AC power supply outlet (not shown) and inputs a rated AC 100 V to the electronic device, a DC voltage of approximately 7 V is supplied from the standby power supply 2. Output
The Zener diode 3 and the Zener diode 8 do not conduct, and the transistor TR1 is off. Control microcomputer 9
Is supplied with driving power through the three-terminal regulator 13, and receives a signal from the remote controller 92 at the light receiving unit 91 to control the electronic device. Therefore, the switch 15 is controlled to be openable and closable by the operation of the remote controller 92. Overvoltage protection circuit switch 4
Is closed because the transistor Tr1 is off and the transistor Tr2 is on, and the relay RL is on.

When the user of the electronic device erroneously connects the input terminal 1 to an AC power source higher than the rating, for example, a 220 V power source, or when a high voltage of a lightning surge is input, the Zener diode 3 and the Zener diode 3 A voltage equal to or higher than the Zener voltage is applied to the diode 8 to conduct. When the Zener diode 3 is turned on, the transistor TR1 is turned on, and the turned-on transistor RL for the relay RL is turned off, so that the relay RL is turned off, the overvoltage protection circuit switch 4 is opened, and the main power supply is turned off.
However, the electronic device is protected from overvoltage.

At the same time as the Zener diode 3 is turned on, the Zener diode 8 is turned on and a voltage is applied to the positive-phase input terminal of the comparator 5, so that an H level signal is output. When the control microcomputer 9 receives the H-level signal from the comparator via the terminal t3, the control microcomputer 9 receives the signals at the terminals t1 and t1.
2 is set to H level, for example.

When the terminal t1 of the control microcomputer 9 becomes H level, the power supply latch circuit 7 having a function as a thyristor is turned on, and the transistors TR2, the relay RL and the switch 4 are kept off, and the power supply circuit is turned off. Keep off state. Therefore, in this state, the user
The electronic device does not operate even if the power switch 15 is turned on by using such a method.

The power supply latch circuit 7 is configured as a thyristor using a transistor, and latches off the transistor Tr2 for the relay RL. If the overvoltage protection circuit is constituted only by the control microcomputer 9, a malfunction of the control microcomputer 9 may occur due to a power surge or the like, and the transistor T
By configuring a double protection circuit with r1, the operation accuracy is improved. In the case of using only the transistor Tr1, if a pulse-like surge voltage is applied, the transistor Tr1 may be repeatedly turned on / off. However, the accuracy of the operation is improved by forming the power supply latch circuit 7 and the double protection circuit. .

When the terminal t2 of the control microcomputer 9 goes to the H level, the transistor Tr3 of the display circuit 6 conducts, the light emitting diode 61 emits light, indicating that the electronic device is connected to the abnormal voltage source. . In this case, if the level of the terminal t2 is set so as to repeat the H level and the L level,
The light emitting diode 61 is controlled to blink.

When the user confirms that the light emitting diode 61 is emitting light, if the input terminal 1 of the AC power supply is disconnected from the AC power supply, the overvoltage protection circuit is reset, returns to the initial state, and returns to the appropriate AC power supply. If the input terminal 1 is connected again, the electronic device operates normally.

The operation of the control microcomputer 9 of the present invention when an overvoltage is applied will be described. FIG. 2 is a flowchart showing the operation of the control microcomputer of the present invention. In FIG. 2, first, in step S1, it is determined whether the detected voltage is equal to or higher than the reference voltage. When the voltage is equal to or higher than the reference voltage, the Zener diode 8 is turned on, and the comparator 5 outputs an H level signal.
, It can be determined that an overvoltage has been applied to the input terminal 1. If "NO", the process returns to the step S1.

If the detected voltage is equal to or higher than the reference value, the process proceeds to step S2, where the protection circuit is activated and the protection circuit switch is opened.
ED) is displayed, and the process proceeds to step S3. Even if the power switch is turned on by the remote controller 92 in step S3, the main power is kept off because the latch circuit 7 is working in step S4.
The LED is kept blinking.

The protection circuit 12 functions when the transistor Tr1 does not operate, and when the switch 4
Has a protection function in the event that is not turned off. That is,
When an overvoltage (for example, 200 V) is supplied, the output of the driving switching power supply 16 is controlled so that the voltage is instantaneously reduced. Then, the diode of the protection circuit 12 is turned on, the transistor of the protection circuit 12 is turned on, the power supply latch circuit 7 is turned on, and the transistor Tr2 is turned off.
And the main power of the device is turned off, so that the electronic device is protected. The standby power supply 2 itself has an internal temperature fuse (not shown) and is protected.

[0025]

According to the present invention, as described above, the control microcomputer 9 turns off the main power supply and latches the control output when it judges that an overvoltage has occurred. Main power is kept off. Therefore, the following effects can be obtained. 1. Even if the user malfunctions and the AC power is excessively input, the device will not be damaged. 2. The equipment will not be damaged by excessive input such as lightning surge. 3. In countries with multiple voltages where power supply conditions are different,
Even if there is an erroneous input connection, the main power supply of the set is instantly turned off and an abnormality is displayed by turning on the LED, thereby maintaining safety.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a power supply control device including an overvoltage protection circuit according to the present invention.

FIG. 2 is a flowchart showing the operation of the control microcomputer of the present invention.

FIG. 3 is a block diagram of a conventional overvoltage protection circuit of an electronic device.

[Explanation of symbols]

1 AC power supply input terminal, 2 Standby power supply, 3
Zener diode, 4 comparator, 6 overvoltage display circuit, 7 latch circuit, 8 Zener diode, 9
Control microcomputer, Tr1, Tr2, Tr3 transistors.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G053 AA09 AA10 BA04 CA01 DA03 EA01 EA04 EC01 FA06 5H006 AA04 AA05 CA08 CA12 CB01 CC01 DA04 DB01 DC05 FA01 GA04 5K048 AA06 BA01 EB02

Claims (7)

[Claims] 1. A DC conversion means for supplying a DC voltage obtained by converting an AC power supply, a voltage detection means for detecting a level of the DC voltage obtained by the DC conversion means, and an operation of an operation button Control information forming means for forming control information according to a state; and controlling the main load circuit driven by the AC power supply to be in a non-operating state when the detected voltage is higher than a predetermined voltage. And control means for controlling the main load circuit driven by the AC power supply to continue the non-operating state even when an ON instruction is given based on the control information from the control information forming means. Power supply control device for electronic equipment. 2. A power supply device connected to an AC power supply for obtaining a desired DC voltage, comprising: voltage detection means for rectifying the AC power supply and detecting a level of the DC voltage obtained by smoothing; Control information forming means for forming control information according to the operation state of the control circuit; and controlling the main load circuit driven by the AC power supply to be in an inactive state when the detected voltage is higher than a predetermined voltage. And a latch means for latching a signal output from the control means after the non-operation state, and keeping the non-operation state of the main load circuit driven by the AC power supply. Power control device for electronic equipment. 3. A DC conversion means for supplying a DC voltage obtained by converting an AC power supply; a voltage detection means for detecting a level of the DC voltage obtained by the DC conversion means; Receiving means for receiving a remote control signal sent from the machine, forming control information according to the received remote control signal, and, when the detected voltage is higher than a predetermined voltage, being driven by the AC power supply. The main load circuit controlled by the AC power supply is controlled to be in an inactive state, and the main load circuit driven by the AC power supply is also inactive when an ON instruction is given based on a remote control signal from the receiving means. Control means for controlling so as to continue the power supply control. 4. The power supply control device for an electronic device according to claim 1, further comprising a display unit for displaying that the main load circuit driven by the AC power supply is in an inactive state. 5. A step of detecting a level of a DC voltage obtained from an AC power supply, a step of forming control information according to an operation state of an operation button, and a step of detecting the detected voltage from a predetermined voltage. When it is high, the main load circuit driven by the AC power supply is controlled so as to be in a non-operating state, and the main load circuit driven by the AC power supply is also driven when an ON instruction is given based on the control information. Controlling the electronic device to maintain the non-operating state. 6. A voltage detecting step of detecting a level of a DC voltage obtained by converting an AC power supply, a step of forming a control signal according to a received remote control signal, and Controlling the main load circuit driven by the AC power supply to be in an inactive state when the voltage is higher than a predetermined voltage; and also when an ON instruction is given based on the received remote control signal. Controlling the main load circuit driven by the AC power supply to remain in a non-operating state. 7. The power supply control method for an electronic device according to claim 5, wherein an indication that the main load circuit driven by the AC power supply is in an inactive state is displayed.