JPH11119842A - Pretective circuit, protective processing control method, and medium for recording protective processing control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective circuit and a protective processing control method by which the cause of an abnormality is specified and also the efficiency of correction work is improved, and to provide a medium in which a protective processing program is recorded. SOLUTION: When the voltage value of DC 5V line to DC 180V line in a television set is monitored by A/D input ports A/D1 to A/D4 of a microcomputer 70 to detect voltage abnormality, and a power relay 60 is turned off at the time of detection of the voltage abnormality to interrupt power supply, since a set of each A/D input port is changed by a remote controller 80 and it is made that the power supply is not interrupted even when the abnormality occurs, the work efficiency of specifying abnormality occurrence place can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection circuit provided with a microcomputer, a protection processing control method for the protection circuit, and a medium recording a protection processing control program.

[0002]

2. Description of the Related Art Conventionally, a technique shown in FIG. 8 is known as this kind of technique. Referring to FIG.
A / D port (A / D) is provided. Diodes D1 to D1 connected in parallel with each other
Connected to the anode side of D3 and a diode D
The cathode side of each of D1 to D3 has a DC5V line,
It is connected to a power line consisting of a C9V line and a DC25V line. Of this DC power line, DC9
The voltage on the V line and the DC 25 V line is appropriately divided, and the voltage at the connection end between the diodes D2 and D3 is reduced to 5V.

Further, an A / D port (A / D
D) is pulled up to the positive power supply VDD between the diodes D1 to D3 and a voltage of 5V is applied, so that no current flows through the diodes D1 to D3.
Therefore, the input voltage of the A / D port of the microcomputer 1 is also constant at 5V. However, when an abnormality occurs in any one of the DC power supply lines and the voltage value decreases,
A current flows through the diodes D1 to D3, and A /
The input voltage of the D port (A / D) also decreases.

[0004] The microcomputer 1 monitors the input voltage of the A / D port (A / D), determines that an abnormality has occurred when the input voltage falls below a predetermined voltage value, and sets a predetermined power control signal to a low level to set a main power. The power was turned off to protect various electronic components. On the other hand, in the system disclosed in Japanese Patent Application Laid-Open No. 5-250222, a monitored CPU system having one or more CPUs is set to execute and non-execut At the same time, the data is transmitted with a time code, and the data is input to a CPU monitoring circuit having a monitoring CPU.
The U monitoring circuit monitors and saves the data at regular intervals,
The saved data is displayed on the monitor. Here, the CPU monitoring circuit resets the CPU of the monitored CPU system when the system abnormality is detected a predetermined number of times. However, the output data of the monitored CPU system is stored for a certain period, and the stored data is displayed on the monitor. As a result, the situation at the time of failure occurrence can be grasped.

[0005]

The above-mentioned conventional protection circuit has the following problems. In the former case, when an abnormality occurs in any one of the DC5V line to the DC25V line, the main power supply is turned off, so that the power supply line in which the abnormality has occurred cannot be specified. Further, when investigating the cause of the abnormality on the power supply line, even if the operator turns on the main power again, the protection circuit operates and the main power is turned off, so that the cause of the abnormality cannot be investigated. Therefore, in such a case, the solder of the diodes D1 to D3 connected by soldering is floated, the protection circuit is disabled, the main power supply is turned on again, and the cause of the abnormality is repaired. After the completion, the diodes D1 to D3 are soldered again, and the repair work is troublesome.

On the other hand, in the latter, although the situation at the time of occurrence of an abnormality can be grasped, its application range is limited to the detection of a system abnormality such as a data error and the like, and the above-mentioned power line is not used. It cannot be used for abnormality detection. The present invention has been made in view of the above problems, and has recorded a protection circuit, a protection processing control method, and a protection processing control program capable of easily specifying the cause of an abnormality and improving the efficiency of repair work. The purpose is to provide media.

[0007]

In order to achieve the above object, according to the present invention, a protection process is executed based on input signals for abnormality detection from a plurality of monitored circuits provided in a main device. A protection circuit that detects an abnormality based on an input signal to each port with a microcomputer having a plurality of ports capable of inputting signals and performs a predetermined protection process; A protection process execution control means for changing the port setting so that the protection process is not executed even when an abnormality occurs is provided.

In the invention according to claim 1 configured as described above, when an abnormality occurs, the protection processing execution means determines the abnormality based on an input signal from a monitored circuit input to each port of the microcomputer. Detects and attempts to execute a predetermined protection process. However, if the protection processing is executed, the cause of the abnormality may not be specified.In order to prevent the protection processing from being executed for such a reason, the port setting is changed by the protection processing execution control means. So that no abnormality is detected at the same port. Therefore, as a specific method, a port may be simply turned off, an input port may be changed to an output port, and various methods may be applied as long as the microcomputer can not receive signals. can do.

When an abnormality detection signal is input to a port of a microcomputer, if the signal is an analog signal, it must be converted into a digital signal and input. Of course, given A
Although it is possible to perform such signal conversion by installing a / D converter separately, it is not necessarily limited to this configuration. An example of a specific configuration in this case is claim 2
The invention according to claim 1 is a protection circuit according to claim 1,
Each of the plurality of ports is constituted by an A / D port. In other words, the analog abnormality detection signal is not converted into a digital signal, but is directly converted by the microcomputer's A / D converter.
Fill in the port.

As described above, although the analog / digital signal type is arbitrary, it goes without saying that the signal content is also arbitrary. As an example, the invention according to claim 3 is based on claim 1 or claim 1. 3. The protection circuit according to any one of 2), wherein the plurality of ports each receive a voltage signal as the input signal, and the protection processing execution unit detects a voltage abnormality based on the voltage signal.

In the third aspect of the present invention, a voltage signal is input to a plurality of ports of the microcomputer, and the protection processing execution means detects an abnormality based on the voltage signal. I do.

As an example of a specific configuration for detecting an abnormality based on a voltage signal, the invention according to claim 4 is as follows.
4. The protection circuit according to claim 3, wherein said protection processing execution means determines that said port is normal when said input signal is at a high level and is abnormal when said input signal is at a low level. There is a configuration to determine.
In the invention according to claim 4 configured as described above, each port of the microcomputer is connected to a positive power supply via a certain element, and a constant positive voltage is input. Here, when an abnormality occurs, current flows to the element side according to the location where the abnormality occurs, and the port input voltage of the microcomputer decreases. Therefore, the input signal of the same port becomes high level or low level depending on the presence or absence of abnormality,
The microcomputer determines that the input signal is normal when it is at a high level, and determines that it is abnormal when it is at a low level.

When an abnormality occurs, the cause of the abnormality is repaired. It is preferable that a function for facilitating identification of the cause is provided. As an example, the invention according to claim 5 is a protection circuit according to any one of claims 1 to 4, wherein the protection processing execution means includes:
A predetermined display is provided, and the status of the detection of the abnormality is displayed on the display. Claim 5 configured as described above.
In the invention according to the first aspect, the detection status of the abnormality is displayed on a predetermined display. For example, the detection status on a small liquid crystal display may be displayed, or when an abnormality occurs, an LED may be lit according to the cause of the abnormality, and the user can visually recognize the display. And use it as a guide to identify the cause of the abnormality.

As the contents of the protection processing, various kinds of contents can be considered according to the application target of the protection circuit. For example, the CPU may be reset as in the above-described conventional technique, or may have another content. As an example, the invention according to claim 6 is the protection circuit according to any one of claims 1 to 5, wherein the protection processing execution unit turns off a main power supply of the main device when an abnormality is detected. There is.

As a content of the protection process in the case of occurrence of an abnormality in the power supply system, power supply to various electronic components is often cut off. When the protection circuit detects an abnormality in a plurality of power supply circuits as a monitored circuit, a protection process is executed when the abnormality occurs, and when the main power is turned off and power supply to various electronic components is cut off, the abnormality is detected. The cause may not be identified. Therefore, according to claim 7 configured as described above, even when an abnormality occurs, the power supply is not interrupted, and it is possible to specify the location of the abnormality in the power supply system.

Although there are various types of electrical products provided with a plurality of power supply circuits, a television can be cited as an example of electrical products that are used on a daily basis. 2. Description of the Related Art Generally, a television includes a plurality of electronic components having different supply voltages, such as an audio system circuit, a deflection IC, and a picture tube, and supplies power by appropriately changing the voltage by a plurality of power supply circuits. Therefore, when a plurality of power supply circuits in a television are monitored circuits, when an abnormality occurs, the repair worker once changes the circuit configuration so that the protection circuit does not operate, and returns to the original state after the work is completed. In fact, it was necessary to perform such a troublesome task.

According to a seventh aspect of the present invention, in the protection circuit of the first to sixth aspects, the main device is a television, and the monitored circuit is
A power supply circuit in the television, an input signal obtained by dividing an output voltage of the power supply circuit to a predetermined voltage is supplied to a plurality of ports of the microcomputer, A port setting means for setting a port for performing or not performing the protection processing, wherein the protection processing execution means includes a port setting state of the port setting means, and an abnormality of the television when an abnormality occurs based on an input signal of the port. The main power is turned off.

In the invention according to claim 7, the monitored circuit is a plurality of power supply circuits of a television which is a main device, and a plurality of ports of the microcomputer are provided with output voltages of the same power supply circuit. Is divided and input so as to be a predetermined voltage. Usually, the protection processing execution means monitors the input of this port to detect a voltage abnormality of the power supply circuit,
Turn off the main power of the television when an error occurs. However, if the port is set by the port setting means so that the protection processing is not executed even when an abnormality occurs, the protection processing execution means does not turn off the main power of the television.

In order to prevent the protection process from being executed when an abnormality occurs, several modes are conceivable. For example,
If the protection processing is not executed when an abnormality is detected at an arbitrary port, there is an advantage that it is easy to at least identify the cause of the abnormality, but it is not necessarily limited to this configuration. As one example, the invention according to claim 8 is the protection circuit according to any one of claims 1 to 7, wherein the protection processing execution control means determines whether or not each of the plurality of ports detects an abnormality. Are individually selectable.

In the invention according to claim 5 configured as described above, since it is possible to individually select whether or not to detect an abnormality for each port of the microcomputer, various ports can be selected based on the will of the repair worker. You can make settings.
For example, when a plurality of abnormalities occur at the same time, even if it is selected not to execute the protection processing when an abnormality occurs in one port, the protection processing may be executed due to another abnormality cause. At this time, the repair worker can recognize that a plurality of abnormalities have occurred at the same time, and can easily identify the abnormalities by appropriately selecting a port for which the abnormality detection is invalidated.

As described above, even if the control is performed so as not to execute the protection processing, it is not necessary to limit the apparatus to a substantial apparatus, and it can be easily understood that the apparatus functions as a method. Therefore, according to a ninth aspect of the present invention, an input signal for abnormality detection is supplied from a plurality of monitored circuits provided in a main device to a plurality of ports of the microcomputer capable of inputting signals. A protection processing control method for executing a predetermined protection process when an abnormality is detected based on an input signal to the port, wherein the setting of the port is changed so that the protection process is not executed even when an abnormality occurs There is.

That is, there is no difference that the present invention is not necessarily limited to a substantial device and is also effective as a method. In the case of software that controls not to execute the protection process as an embodiment of the idea of the present invention, the software naturally exists on a recording medium on which such software is recorded, and must be used. As one example, the invention according to claim 10 is to supply an input signal for abnormality detection from a plurality of monitored circuits provided in a main device to a plurality of ports capable of inputting signals in a microcomputer, and to each port. A storage medium storing a protection processing control program for executing a predetermined protection processing when an abnormality is detected based on an input signal of the input port, wherein the setting of the port is changed so that the protection processing is not executed even when an abnormality occurs. There is a configuration.

Of course, the recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium to be developed in the future. Also, the duplication stages of the primary duplicated product, the secondary duplicated product, and the like are equivalent without any question. In addition, the present invention is not limited to the case where the present invention is used even when the supply method is performed using a communication line, and the same applies to a case where the information is written on a semiconductor chip.

Further, even when a part is implemented by software and a part is implemented by hardware, there is no difference in the concept of the present invention. It may be in a form that is appropriately read in accordance with it.

[0025]

As described above, according to the present invention, when a plurality of abnormality detection signals from the monitored circuit are input to the ports of the microcomputer and the microcomputer executes the protection processing when an abnormality occurs, the abnormality is detected. Since the protection process is not performed even at the time, it is possible to provide a protection circuit capable of easily specifying the cause of the abnormality and improving the efficiency of the repair work.

According to the second aspect of the present invention, when an analog input signal is input to a port of the microcomputer, an A / D converter for converting the input signal into a digital signal is not required, so that the circuit configuration is simplified. Can be Furthermore, according to the third aspect of the present invention, since the voltage signal is used as the input signal for abnormality detection, abnormality detection based on a simple change in signal level can be performed. Furthermore, according to the invention according to claim 4,
An abnormality can be detected based on a voltage signal with a simple circuit configuration using a pull-up connection.

Further, according to the invention according to claim 5,
Since the detection status of the abnormality is displayed on the display, it is easy to identify the cause of the abnormality. Since the abnormality detection status is displayed on the display, it is easy to identify the abnormality detection location. Further, according to the invention according to claim 6, according to the invention according to claim 7, it is possible to provide a protection circuit suitable for use in detecting an abnormality in a power supply system. further,
According to the invention according to claim 7, it is possible to provide a protection circuit suitable for use in detecting an abnormality in a power supply system of a television.

Further, according to the invention of claim 8,
In each of the plurality of ports, whether or not to detect an abnormality can be individually selected, so that the efficiency is high. Further, when there are a plurality of causes of the abnormality, it is easy to specify the cause. Further, according to the invention of claim 9, it is possible to provide a protection processing control method capable of easily specifying the cause of the abnormality and improving the efficiency of the repair work. Further, according to the tenth aspect of the present invention, it is possible to provide a medium recording a protection processing control program capable of easily specifying the cause of an abnormality and improving the efficiency of repair work.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic circuit diagram showing a power supply peripheral circuit of a television to which a protection circuit according to an embodiment of the present invention is applied. In FIG. 1, a bridge type rectifier circuit 10 extracts a DC component from an AC 100 V power supply and outputs a smoothed output. A switching control circuit 20 intermittently supplies the smoothed output to a primary side of a switching transformer 30. The output from the secondary winding 30a in the switching transformer 30 is rectified and smoothed by a rectifier circuit 40a to generate a DC5V power supply line.
An audio circuit and the like (not shown) are supplied with power from the V line.

Similarly, the output from the secondary winding 30b of the switching transformer 30 is rectified and smoothed by the rectifier circuit 40b to generate a DC9V power supply line.
A horizontal drive, a deflection IC, and the like (not shown) receive power supply from the V line and also supply power to the primary side of an FBT (flyback transformer) 50. FBT50 is
The secondary side outputs a high voltage to generate a DC 25 V power line, and a picture tube (not shown) or the like receives power supply from the DC 25 V line.

A power relay 60 is interposed in front of the bridge type rectifier circuit 10.
Is turned on / off to supply and cut off power to the above-described audio system circuit, horizontal drive, deflection IC, picture tube, and the like. Specifically, a switching transistor Tr1 for driving the relay coil 60a of the power relay 60 is provided at an appropriate position, and a signal output terminal (P
W), a predetermined power control signal is applied. When the power control signal goes high, the power relay 60 is turned on to supply power, and when the power control signal goes low, the power relay 60 is turned on. It turns off and the power supply is cut off. Since the microcomputer 70 is supplied with power from a backup power supply taken out from a stage preceding the power relay 60, the power relay 6
It always operates with power supplied without depending on ON / OFF of 0.

The microcomputer 70 has a signal output terminal (PW) as described above, and also has four A / D input ports A / D1 to A / D4. Among the A / D input ports, the anode sides of the diodes D1 to D3 are connected to the A / D input ports A / D1 to A / D3, respectively, and the cathode side is a DC5V line and a DC9V, respectively.
Line and a DC 25V line. Note that D
The C9V line and the DC25V line are appropriately divided to reduce the voltage at the cathode-side connection terminals of the diodes D2 and D3 to 5V.

The A / D input ports A / D1 to A / D3 are
Since the pull-up connection is made to the positive power supply VDD between the diodes D1 to D3 and a voltage of 5V is applied, the voltage of the DC5V line to the DC25V line is normal,
That is, the voltage on the cathode side of the diodes D1 to D3 is 5
In the case of V, no current flows through the diodes D1 to D3, and the input voltage to the A / D input ports A / D1 to A / D3 becomes 5V. However, DC5V line to DC
When a voltage abnormality occurs in the 25V line and the voltage value of the power supply line in which the voltage abnormality has occurred decreases, the voltage on the cathode side of the corresponding diode decreases, and a current flows through the diode. Then, the input voltage of the A / D input port to which the diode is connected is reduced to a value lower than 5V. The microcomputer 70 controls the A
Based on a decrease in the input voltage of the / D input ports A / D1 to A / D3, the above-described voltage abnormality of the power supply line is detected, and the power control signal is set to low level to cut off the power supply.

The A / D input port A / D4 is connected to the anode side of a Zener diode ZD1, and the cathode side of the Zener diode ZD1 is connected to a DC180V line via a resistor R1. DC180
Although the V line is not described in detail, power is supplied and cut off in accordance with ON / OFF of the power relay 60.
Although the output voltage of the DC 180 V line is divided by the resistor R1 and a reverse voltage is applied to the Zener diode ZD1, no reverse current flows in the Zener diode ZD1 due to the reverse voltage in a normal state.

However, when a voltage abnormality occurs in the DC 180 V line and an overvoltage is supplied to the Zener diode ZD1, a reverse current flows and a voltage is input to the A / D input port A / D4. Also in this case, the microcomputer 70 determines that a voltage abnormality has occurred, and cuts off the power supply by setting the above-described power control signal to a low level. Further, the microcomputer 70 has a program ROM 71, and executes the protection processing control program recorded in the program ROM 71 to detect the above-described voltage abnormality in the power supply line. Next, a specific processing procedure of the microcomputer 70 will be described with reference to a flowchart of the protection processing control program shown in FIG.

In FIG. 2, in step S110, it is determined whether the A / D input port to be monitored is on. Immediately after the power is turned on, a determination is made on the A / D input port A / D1, and at this time, the power control signal is at a high level.
The microcomputer 70 stores a port setting table as shown in FIG. 3 in a non-volatile storage medium such as an EEPROM, and for each of the A / D input ports A / D1 to A / D4, the voltage of the corresponding power supply line. Whether or not to detect an abnormality can be set. In the figure, the detection of abnormal voltage is performed at the A / D input port set to ON, and the detection of abnormal voltage is not performed at the A / D input port set to OFF. The details will be described later.

The setting of the A / D input port can be performed through a remote controller 80 attached to the television of the main body. As shown in FIG. 4, the remote controller 80 includes a main power key, an input switching key, and a channel key. In addition to the normal operation keys such as A / D1 to A / D4, four types of A
A / D input port setting key 80a is provided. The A / D input port setting key 80a is a hidden key that is covered by a cover (not shown) so that the user does not touch it during normal operation.

In this embodiment, the remote controller 80 is provided with a dedicated A / D input port setting key 80a.
By operating the / D input port setting key 80a, the A / D
Although the input / output ports A / D1 to A / D4 are configured to be turned on / off, it is needless to say that the present invention is not limited to this configuration. For example, a plurality of normal operation keys of the remote controller 80 are pressed to shift to the setting mode. In this setting mode, the number keys are pressed down to turn on / off the A / D input ports A / D1 to A / D4. You may be able to set it off.

Each time the A / D input port setting key 80a is depressed once, the A / D corresponding to the depressed key is pressed.
The input port setting can be switched on / off. Specifically, a predetermined infrared remote control signal is transmitted from the remote controller 80, and the infrared remote control signal is transmitted to a remote control signal receiving section 81 connected to the microcomputer 70. The microcomputer 70 decodes the digital signal and switches the setting. In this sense, the microcomputer 70, the remote controller 80, and the remote controller signal receiving unit 81 constitute a port setting unit. In this embodiment, the A / D is operated by remote control operation.
Although the setting of the input port is changed, it goes without saying that the setting may be changed by operating keys on the television main body side, and the setting can be changed as appropriate.

In step S110, the A /
If the setting of the D input port is on, step S120
In step S130, a voltage abnormality detection process is performed based on the input voltage of the A / D input port. In this voltage abnormality detection process, when the A / D input ports to be monitored are A / D1 to A / D3, an abnormality occurs when the input voltage of the A / D input port falls below a predetermined voltage value. And judge. In the present embodiment, 80% of the reference voltage 5V, that is, 4V is used as the threshold, and when the input voltage to the A / D input port becomes 4V or less, it is determined that an abnormality has occurred. When the A / D input port to be monitored is A / D4, if a voltage is input to the A / D input port, it is determined that an abnormality has occurred. If it is determined that an abnormality has occurred, the power control signal is set to a low level in step S140. Then, the power relay 60 is also turned off, and the power supply is cut off.

On the other hand, if the setting of the A / D input port to be monitored is off in step S110, or
If it is determined in step S130 that there is no abnormality,
In step S150, the monitoring target is changed to the next A / D input port. That is, immediately after the power is turned on, the A / D input port to be monitored is A / D1, but unless an abnormality is detected, the A / D input port is changed to A / D2, A / D3, A / D1.
4, and after the processing related to A / D4 is completed, the monitoring target is moved to A / D1 again, and the same loop is repeated.

A display 90 is connected to the microcomputer 70. As shown in FIG.
/ D input port setting (ON / OFF) and the voltage abnormality detection status (NORM./ABNORM.) In the power supply line corresponding to each A / D input port are displayed on the display unit 90 in real time. It is. Although a specific configuration can be realized by applying various known techniques, it is not described in detail here, but even when the power supply is turned off by turning off the power relay 60, the microcomputer 70, Electric power is supplied to the remote control signal light receiving unit 81 and the display unit 90. By visually recognizing the display contents of the display unit 90, it is possible to identify a power supply line in which an abnormality has occurred. In the above sense, the microcomputer 70 and the display 90 constitute a protection processing execution unit, and the microcomputer 70, the remote controller 80 and the remote control signal receiving unit 81 constitute a protection processing execution control unit.

When the power line in which the abnormality has occurred is specified, the setting of the A / D input port corresponding to the power line is turned off, and the power is turned on again. Then, the microcomputer 7
0 is also reset, the power control signal goes high, and power supply is resumed. In this case, the A / D
Step S120 and Step S for Input Port
Since the abnormality detection processing of 130 is not executed, the power relay 60 is not turned off and the power supply is not cut off. As described above, the power supply state can be maintained even when a voltage abnormality occurs by operating the remote controller, and the work efficiency of the repair worker is also improved.

In this embodiment, a dedicated display 90
Is provided to display the setting of the A / D input port and the abnormality detection status, but it is needless to say that the present invention is not limited to this configuration. For example, since the protection circuit is applied to a television, the protection circuit may be displayed on a television screen using an OSD circuit or the like. However, in this case, it is needless to say that the video output is at least possible even if an abnormality occurs. The above-described protection processing control program is merely an example, and may be changed as appropriate.

Next, the operation of this embodiment configured as described above will be described with reference to specific examples. FIG. 6 is a time chart showing the voltage value of the DC9V line, the input voltage of the A / D input port A / D2, and the power control signal when the port setting is on, and FIG. 7 is a time chart when the port setting is off. Are similarly shown.
In FIG. 6, when an abnormality occurs in the DC9V line and the voltage value decreases, the applied voltage on the cathode side of the diode D2 falls below 5V, and a current flows through the diode D2.
Then, it is assumed that the input voltage of the A / D input port A / D2 drops and the input voltage becomes 4 V or less.

The microcomputer 70 has an A / D input port A / D
1 to A / D4 are sequentially monitored to detect anomalies (steps S110 to S130, S130
150), the input voltage of the A / D input port A / D2 is 4 V
When it is below, it is determined that an abnormality has occurred in the DC9V line, and the power control signal is set to low level (step S140). Then, the transistor Tr1 is turned off, and the power supply to the relay coil 60a is cut off.
The power relay 60 is turned off, and the power supply to the audio system circuit, horizontal drive, deflection IC, picture tube, and the like is cut off.
Even when the power supply is interrupted in this way, the microcomputer 70, the remote control signal receiving unit 81, and the display 90 receive the power supply, and the microcomputer 70 displays on the display 90 that an abnormality has occurred in the DC9V line. I do.

The repair worker who visually recognizes the displayed contents is
Recognizing that an abnormality has occurred in the C9V line, depress the A / D input port setting key 80a of the remote
After turning off the port setting of the / D input port A / D2, the power is turned on again. After the power is turned on again, the microcomputer 70 is reset and the power control signal becomes high level, so that power is supplied. However, since the abnormality in the DC9V line has not been repaired yet, as shown in FIG.
Both the voltage value of the V line and the input voltage of the A / D input terminal A / D2 decrease.

The microcomputer 70 has an A / D input port A / D
Voltage abnormality detection processing (step S
120, in step S130), it is detected that the setting of the A / D input port A / D2 is turned off (step S110). Never goes low. Therefore, the power supply is not interrupted, and the repair worker can investigate the location where the abnormality has occurred in the state of power supply to each power supply line, and does not need any troublesome work such as changing the circuit configuration.

As described above, the DC5 in the television
The voltage value of the V line to the DC 180 V line is
0 at the A / D input ports A / D1 to A / D4 to detect abnormal voltage,
To shut off the power supply by turning off
Since the setting of each A / D input port was changed via 0 to prevent the power supply from being interrupted even when an abnormality occurred,
The cause of the abnormality can be easily specified, and the efficiency of the repair work can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of a power supply peripheral circuit of a television to which a protection circuit according to an embodiment of the present invention is applied.

FIG. 2 is a flowchart of a protection processing control program.

FIG. 3 is a port setting table.

FIG. 4 is a front view of the remote controller showing operation keys arranged on the remote controller.

FIG. 5 is a diagram showing display contents of a display device.

FIG. 6 is a time chart of the voltage value of the DC9V line, the input voltage of the A / D input port A / D2, and the power control signal when the port setting is ON.

FIG. 7 is a time chart of the voltage value of the DC9V line, the input voltage of the A / D input port A / D2, and the power control signal when the port setting is off.

FIG. 8 is a schematic circuit diagram of a protection circuit according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Bridge-type rectifier circuit 20 ... Switching control circuit 30 ... Switching transformer 40a, 40b ... Rectifier circuit 50 ... FBT 60 ... Power relay 70 ... Microcomputer 71 ... Program ROM 80 ... Remote control 81 ... Remote control signal light receiving part 90 ... Display

Claims (10)

[Claims] A protection circuit provided in a main device and executing a protection process based on input signals for abnormality detection from a plurality of monitored circuits, comprising: a microcomputer having a plurality of ports capable of inputting signals; Means for detecting an abnormality based on an input signal to each port and executing a predetermined protection processing, and changing a port setting in the microcomputer so that the protection processing is not executed even when an abnormality occurs. And a protection processing execution control means. 2. The protection circuit according to claim 1, wherein each of the plurality of ports comprises an A / D port. 3. The protection circuit according to claim 1, wherein each of the plurality of ports inputs a voltage signal as the input signal, and the protection processing execution means outputs the same voltage signal. A protection circuit for detecting an abnormal voltage on the basis of a voltage. 4. The protection circuit according to claim 3, wherein said protection processing execution means determines that said ports are normal when said ports are pulled up and said input signal is at a high level. A protection circuit characterized by determining an abnormality at low level. 5. The protection circuit according to any one of claims 1 to 4, wherein the protection processing execution means includes a predetermined display, and displays an abnormality detection status on the display. Features protection circuit. 6. The protection circuit according to any one of claims 1 to 5, wherein said protection processing execution means turns off a main power supply of said main device when an abnormality is detected. . 7. The protection circuit according to claim 1, wherein the main device is a television, and the monitored circuit is a power supply circuit in the television.
An input signal obtained by dividing the output voltage of the power supply circuit to a predetermined voltage is supplied to the plurality of ports of the microcomputer, and the protection processing execution control means determines whether or not to execute the protection processing when an abnormality occurs. A port setting unit configured to perform port setting, wherein the protection processing execution unit turns off a main power supply of the television when an abnormality occurs based on a port setting state of the port setting unit and an input signal of the port. And protection circuit. 8. The protection circuit according to claim 1, wherein the protection processing execution control means can individually select whether or not to detect an abnormality in each of the plurality of ports. A protection circuit, characterized in that: 9. An abnormality detection input signal is supplied from a plurality of monitored circuits provided in a main device to a plurality of ports of the microcomputer capable of inputting signals, and an abnormality is detected based on an input signal to each port. A protection processing control method for executing a predetermined protection processing when detecting a protection processing, wherein the setting of the port is changed so that the protection processing is not executed even when an abnormality occurs. . 10. An abnormality detection input signal is supplied from a plurality of monitored circuits provided in a main device to a plurality of ports in the microcomputer, to which signals can be input, and an abnormality is detected based on an input signal to each port. A medium for recording a protection processing control program for executing a predetermined protection processing when detecting an error, wherein the setting of the port is changed so that the protection processing is not executed even when an abnormality occurs. Medium on which protection processing control program is recorded.