JP2005027354A - Power control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power control unit in which circuit configuration is not complicated, and which is miniaturized, reduces costs and enhances power saving effect in an operation standby state. <P>SOLUTION: The power control unit for use in an ordinary operating mode and an operation standby mode comprises a switching power source 3 for creating a DC power source for a driving part for portions of an apparatus from an AC commercial power source 1, a microcomputer power source 7 for creating a constant DC voltage for a signal input circuit including a microcomputer 20 with the DC power source of the switching power source 3 as its input, an error amplifying circuit (shunt regulator 15) for performing stable voltage control based on the output voltage of the switching power source 3, and output voltage change means (resistors 16, 17, 18 and transistor 19) for changing the output voltage of the switching power source 20 to be applied to the error amplifying circuit and in the operation standby mode, the output voltage of the switching power source 20 to be applied to the error amplifying circuit is lowered by the output voltage change means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power supply control device for a device having a state of waiting for an operation command from a remote controller, such as a television receiver or an indoor unit of an air conditioner.

  A power supply control device for a device such as a television receiver that has a state of waiting for an operation command from a remote controller (remote control) is used for power saving to wait for a rated operation mode (normal operation mode) and a power-on instruction from the remote control. Some have a standby mode.

  FIG. 5 shows a conventional power supply control device as disclosed in Patent Document 1 below. This power supply control device includes a switching power supply (main power supply circuit) 50 which receives AC (commercial AC power supply) and obtains DC outputs of V1 to VN having different voltage levels, and a DC voltage from the switching power supply 50 via a switching circuit 51. A microcomputer power source (hereinafter referred to as a microcomputer power source) 52 and two error amplifiers 53 and 54 for detecting the output voltage of the switching power source 50 and controlling the switching power source 50, and a switching circuit. 51 performs switching of the error amplifiers 53 and 54 according to the mode switching signal and switching of the DC output supplied from the switching power supply 50 to the microcomputer power supply 52.

  FIG. 6 shows a detailed circuit of a portion excluding the switching power supply 50 of the conventional power supply control device shown in FIG. The microcomputer power supply 52 is composed of a commercially available general-purpose three-terminal regulator REG1, and generates a microcomputer power supply voltage (+5 V). This power supply voltage (+5 V) is supplied to a signal processing circuit including a microcomputer.

  The error amplifier 53 corresponds to the transistor Q4, and the error amplifier 54 corresponds to the transistor Q5. The emitters of the transistors Q4 and Q5 are both connected to the constant voltage diode D6, and the collector is connected to the photocoupler PC1. The output of the switching power supply 50 is controlled by the optical signal. The mode switching signal instructs switching of the transistors Q4 and Q5 and switching of the output V1 or V2 supplied to the three-terminal regulator REG1.

  Next, the operation in the normal operation mode will be described. When a high level signal is input as a mode switching signal input, the transistor Q1 is turned on through the resistor R9, and the collector potential is lowered. The transistor Q2 having a base connected to the transistor Q1 forms a Darlington connection with the transistor Q3. However, when the base potential of the transistor Q2 is lowered, both the transistors Q2 and Q3 are turned off.

  As a result, the diode D1 is turned off, and the power from the output V1 is not supplied to the three-terminal regulator REG1, but the power from V2 is supplied to the three-terminal regulator REG1 through the diode D2, the resistor R11, and the like. At this time, since current does not flow into the resistor R2 from the transistor Q3, the diode D3 is turned on, and the base potential of the transistor Q4 is lowered, whereby the transistor Q4 is turned off and the transistor Q5 is activated. The transistor Q5 causes the switching power supply 50 to operate in the normal operation mode and output a normal operation output voltage.

  Next, the operation in the operation standby mode will be described. When a low level signal is input as a mode switching signal input, the transistor Q1 is turned off, and the transistors Q2 and Q3 connected to the transistor Q1 are turned on. As a result, the diode D1 is turned on via the resistor R6, the transistor Q3, and the resistor R1, and power is supplied from the output V1 to the three-terminal regulator REG1.

  Further, when the transistor Q3 is turned on, the diode D3 is turned off. Thereby, the transistor Q4 becomes active. The resistance ratio R14 / (R13 + R14) of the resistors R13 and R14 connected to the base of the transistor Q4, which is a detection circuit for the output V1, is the resistance ratio of the resistors R15 and R16 that are also the detection circuit and connected to the base of the transistor Q5. By selecting so as to be larger than R16 / (R15 + R16), the voltages of the outputs V1 and V2 of the switching power supply 50 are controlled so as to keep a lower value than in the normal operation mode. For this reason, the output V2 cannot secure the input voltage necessary for the regulator REG1 to output 5V. However, the output V2 is supplied from the output V1 having a voltage higher than V2 through the diode D1, etc. Output can be obtained.

  As another conventional example, as shown in Patent Document 2 below, one switching power supply is configured to output a voltage for the machine and a voltage for the microcomputer. Shut off the voltage output for power supply with a relay switch and lower the oscillation frequency of the switching power supply, or separately provide a switching power supply that outputs the voltage for this machine and a switching power supply that outputs the voltage for the microcomputer, and wait for operation In the mode, a power supply control device that reduces power consumption by turning off the switching power supply that outputs the voltage for this machine by the switch means and lowering the oscillation frequency of the switching power supply that outputs the voltage for the microcomputer is known. .

JP-A-6-6732 Japanese Patent Laid-Open No. 10-23354

  However, the conventional power supply control device as shown in Patent Document 1 requires at least two error amplification circuits, which complicates the circuit, lowers the accuracy of the entire circuit, and is in an operation standby state. As a result, there are problems such as a reduction in power saving effect, an increase in the area occupied by the substrate, and an increase in cost.

  Moreover, the conventional power supply control device as shown in Patent Document 2 secures a voltage for a microcomputer from an intermediate tap of a transformer of a switching power supply and uses a dedicated switching power supply for the microcomputer. Therefore, the circuit becomes complicated, a large occupied volume is required, and it is not suitable for a power supply control device for an indoor unit of an air conditioner that is particularly required to be downsized.

  The present invention has been made to solve the above-described problems, and is a power supply control device that is compact and low-cost without complicating the circuit configuration and that has a large power-saving effect in a standby state. The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, a power supply control device according to the present invention is a power supply control device used in a normal operation mode and an operation standby mode. A switching power source that produces a DC power source, a microcomputer power source that produces a constant DC voltage for a signal input circuit including a microcomputer, and the reference voltage is changed based on the output voltage of the microcomputer power source. A reference voltage changing unit that performs the stable voltage control based on the reference voltage output by the reference voltage changing unit and the output voltage of the switching power supply, and the reference voltage changing unit includes: The reference voltage is lowered during the operation standby mode.

  In the power supply control device according to the next invention, in the above invention, the error amplification circuit includes an operational amplifier that operates based on a differential voltage between a divided voltage obtained by dividing the output voltage of the switching power supply and the reference voltage. And the reference voltage changing means changes a reference voltage applied to the operational amplifier.

  The power supply control apparatus according to the next invention is characterized in that, in the above invention, the output voltage of the switching power supply is controlled by duty ratio control of the reference voltage output.

  The power supply control device according to the next invention has the first voltage detection means for detecting the voltage value of the microcomputer power supply in the above invention, and the voltage value detected by the first voltage detection means is a micro voltage. The reference voltage is changed so as to lower the output voltage of the switching power supply until the signal input circuit including the computer reaches a minimum voltage value at which the signal input circuit can operate.

  The power supply control device according to the next invention is the device according to the above invention, wherein, when the operation standby mode is shifted to the normal operation mode, the switching of the output voltage of the switching power supply to the normal voltage is performed after a predetermined time has elapsed. The drive circuit of each part is operated.

  The power supply control device according to the next invention comprises the second voltage detection means for detecting the output voltage of the switching power supply in the above invention, and the second voltage is detected when the operation standby mode is shifted to the normal operation mode. After the output voltage value detected by the detection means becomes equal to or higher than a specified value, the drive circuit of each part of the device is started to operate.

  The power supply control device according to the next invention is the power supply control device according to the above invention, when the output voltage of the switching power supply detected by the second voltage detecting means at the time of transition from the operation standby mode to the normal operation mode does not exceed a specified value. An abnormality display is performed.

  According to the power supply control device according to the present invention, the output voltage of the switching power supply can be reduced by lowering the reference voltage of the error amplifier circuit during the operation standby mode, so that it is inexpensive, highly accurate and reliable, The power consumption during operation standby can be effectively reduced.

  Embodiments of a power supply control device according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

Embodiment 1 FIG.
FIG. 1 shows Embodiment 1 in which a power supply control device according to the present invention is applied to a power supply control device for an indoor unit of an air conditioner. This power supply control device has a bridge rectifier circuit 2 having a commercial AC power supply 1 connected to an input terminal. Between the output terminals of the bridge rectifier circuit 2, the primary winding 3a of the switching transformer 3 that is a switching power supply and the switching are provided. A series circuit with the converter control unit 4 including the elements and a parallel circuit with the smoothing electrolytic capacitor 5 are connected.

  A DC output unit 11 for 12V is connected to the secondary winding 3b of the switching transformer 3 via a rectifier diode 6. The DC output unit 11 has an input terminal of a three-terminal regulator 7 serving as a microcomputer power source. The coil of the outdoor power supply relay 8, the wind direction motor 9, the operation display lamp 10, and the like are connected. A smoothing electrolytic capacitor 12 is grounded between the rectifier diode 6 and the DC output unit 11.

  The DC output unit 11 is grounded via the current limiting resistor 13, the light emitting element 14a of the photocoupler 14, and the shunt regulator 15 that is an error amplifier, and the current flowing through the light receiving element 14b of the photocoupler 14 is converted to the converter control unit. The feedback current is 4. Further, as the output voltage changing means, the voltage dividing points of the resistors 16 and 17 for dividing and detecting the voltage of the DC output unit 11 are connected to the reference input terminal of the shunt regulator 15, and the detected voltage is connected in parallel to the resistor 17. A series circuit of a resistor 18 and a transistor 19 for changing is connected.

  A microcomputer (microcomputer) 20 that is driven by the output voltage of the three-terminal regulator 7 that is a power source for the microcomputer is provided. The microcomputer 20 includes a remote control receiving circuit 21 that is a signal input circuit and a main body operation switch circuit 22. The on / off state of the drive circuit 23 such as the outdoor power supply relay 8 and the transistor 19 is controlled by the above signal.

  Next, the operation of the power supply control device having the above configuration will be described. The voltage of the commercial AC power supply 1 is full-wave rectified by the bridge rectifier circuit 2 and smoothed by the smoothing electrolytic capacitor 5. When the smoothed voltage exceeds a certain voltage, the converter control unit 4 is activated, and a voltage is generated in the secondary winding 3 b of the switching transformer 3. At this time, the microcomputer 20 is initially set so that the drive circuits 23 such as the transistor 19 and the outdoor power supply relay 8 are turned off.

  Therefore, when the shunt regulator 15 having a reference voltage of 2.5V is used and the voltage dividing ratio between the resistor 16 and the resistor 17 for detecting the output voltage is set to (1/3), the output voltage of the DC output unit 11 is 2.5V. A feedback current flows to the converter control unit 4 by the photocoupler 14 so that the voltage is stabilized to 7.5V, which is three times the voltage of the converter controller 4. The output voltage of the DC output unit 11 is a low voltage of 7.5V, but the voltage of 5V, which is a voltage necessary for the microcomputer power supply, is sufficiently stable by the three-terminal regulator 7, and a voltage of 12V is necessary. Since the outdoor power supply relay 8 and the wind direction motor 9 are off, there is no problem. This mode is the operation standby mode, and significant power saving and power saving are possible.

  When the operation switch of the remote controller or the main body operation switch is pressed, the microcomputer 20 turns on the transistor 19 by a signal from the remote control reception circuit 21 or the main body operation switch circuit 22. When the transistor 19 is turned on, a current also flows through the resistor 18, and the voltage value for detecting the voltage of the DC output unit 11 is determined by the voltage dividing ratio of the resistor 16, the resistor 17, and the resistor 18. If this voltage division ratio is set to (5/24), the output voltage of the DC output unit 11 is set to 12V, which is (24/5) times the reference voltage 2.5V of the shunt regulator 15. The DC output unit 11 is controlled and supplies a stable 12 V voltage necessary for the outdoor supply relay 8 and the like to operate. This mode is the normal operation mode.

  FIG. 2 is a flowchart showing the operation of the microcomputer 20. When the voltage of the commercial AC power source 1 is input and the microcomputer voltage is supplied to the microcomputer 20, the operation of the microcomputer 20 is started. First, when power is turned on, initialization is performed so that the drive circuits 23 such as the transistor 19 and the outdoor power supply relay 8 are turned off (step S10).

  Next, an operation signal from the remote control receiving circuit 21 or the main body operation switch circuit 22 is waited for (step S11). When no operation signal is input, the operation standby mode in which the drive circuits 23 such as the transistor 19 and the outdoor power supply relay 8 are turned off is maintained. When an operation signal is input, the transistor 19 is turned on (step S12), a timer is started (step S13), the timer is counted (step S14), and whether or not a specified time has elapsed from the input of the operation signal. Judgment is made (step S15).

  Waiting for the specified time to elapse, and if the specified time elapses, it is determined that the voltage of the DC output unit 11 has increased to the required voltage by turning on the transistor 19, and the drive circuit 23 that drives the operation display lamp 10 is turned on Normal operation is started (step S16).

  Thereafter, the operation waits for an operation stop signal (step S17). When the operation stop signal is input, the drive circuit 23 is immediately turned off to perform the operation stop operation process (step S18), and the stop operation process is completed. After that, the transistor 19 is turned off and the operation standby mode is set. In this operation standby mode, it again waits for input of an operation signal from the remote control receiving circuit 21 or the main body operation switch circuit 22 (step S11).

  As a result, the operation command is received, and after the transition from the operation standby mode to the normal operation mode, a voltage required for normal operation is reliably supplied by operating the drive unit of each part of the device after a certain time has elapsed. be able to.

  As described above, according to the power supply control device of this embodiment, the output voltage of the switching power supply is reduced by reducing the output voltage of the switching power supply given to the error amplification circuit by the output voltage changing means during the operation standby mode. Therefore, it is possible to effectively reduce power consumption during operation standby with a simple circuit configuration, low cost, high accuracy and reliability.

  Further, according to the power supply control device of this embodiment, the error amplifying circuit is constituted by the shunt regulator, and the output voltage changing means is connected in parallel to the two resistors for dividing the output voltage of the switching power supply and these resistors. Since it is configured by a series circuit of a resistor and a transistor, it is possible to reduce power consumption during operation standby effectively with a simple circuit configuration, at low cost, with high accuracy and reliability.

  Further, according to the power supply control device of this embodiment, when the operation command is received by the signal input circuit and the operation standby mode is shifted to the normal operation mode, the switching power supply output voltage is controlled to the normal voltage. After that, since the drive circuit of each part of the device is operated after a certain period of time, the voltage necessary for normal operation can be reliably supplied.

Embodiment 2. FIG.
FIG. 3 shows Embodiment 2 in which the power supply control device according to the present invention is applied to a power supply control device for an indoor unit of an air conditioner. In FIG. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  In this embodiment, the connection point of the resistors 16 and 17 that divide and detect the voltage of the DC output unit 11 is connected to the inverting terminal of the operational amplifier 24, and the non-inverting terminal of the operational amplifier 24 that is the reference voltage input has three terminals. A resistor 25 is connected to the output of the regulator 7, an electrolytic capacitor 26 is connected to the ground, and a resistor 27 is connected to the output terminal of the microcomputer 20.

  The microcomputer 20 reads the divided voltage values of the resistors 28 and 29 detected by dividing the output voltage of the three-terminal regulator 7, and outputs it to the terminal connected to the non-inverting terminal of the operational amplifier 24 via the resistor 27. The time ratio (hereinafter referred to as duty ratio) of the high level of the pulse signal to be adjusted is adjusted. Thereby, the microcomputer 20 implements the reference voltage changing means.

  Next, the operation of the power supply control device having the above configuration will be described. The voltage of the commercial AC power supply 1 is full-wave rectified by the bridge rectifier circuit 2 and smoothed by the smoothing electrolytic capacitor 5. When the smoothed voltage exceeds a certain voltage, the converter control unit 4 is activated, a voltage is generated in the secondary winding 3b of the switching transformer 3, and the voltage of the DC output unit 11 for 12V increases. At this time, the drive circuit 23 such as the outdoor power supply relay 8 is turned off, and the terminals of the microcomputer 20 connected to the resistor 27 are initially set in the microcomputer 20 so that the duty ratio is 1 (100%).

  Therefore, when the voltage at the non-inverting terminal of the operational amplifier 24 serving as the reference voltage is 5 V and the voltage dividing ratio between the resistor 16 and the resistor 17 for detecting the output voltage is set to (5/12), the voltage of the DC output unit 11 is 5 V. A feedback current flows through the converter control unit 4 by the photocoupler 14 so as to be stabilized at a voltage of 12V which is (12/5) times.

  Thereafter, the microcomputer 20 decreases the output duty ratio of the terminal to which the resistor 27 is connected while monitoring the voltage value of the output of the three-terminal regulator 7 which is a microcomputer power source divided by the resistors 28 and 29. . By reducing the duty ratio, the discharge amount of the electric charge of the electrolytic capacitor 26 increases through the resistor 27, so that the voltage at the non-inverting terminal of the operational amplifier 24, which is the reference voltage, decreases. As the reference voltage decreases, a feedback current flows through the photocoupler 14 and the voltage of the DC output unit 11 decreases.

  By stopping the decrease in the duty ratio before the output voltage of the three-terminal regulator 7 as the microcomputer power supply becomes lower than the limit value (for example, 4.5 V) required for the microcomputer power supply, the DC output unit 11 Is stabilized at 5.9V, which is obtained by adding 1.4V potential difference between the input and output of the three-terminal regulator 7. Although the output voltage of the DC output unit 11 is a low voltage of 5.9V, the limit voltage necessary for the microcomputer power supply is 4.5V, and the outdoor power supply relay 8 and the wind direction motor 9 that require 12V are There is no problem because it is in the off state. This mode is an operation standby mode. In this case as well, significant power saving and power saving are possible.

  When the remote control operation switch or the main body operation switch is pressed, the microcomputer 20 sets the duty ratio of the output terminal to which the resistor 27 is connected to 1 by the signal from the remote control reception circuit 21 or the main body operation switch circuit 22. . As a result, the voltage at the non-inverting terminal of the operational amplifier 24, which is the reference voltage, is fixed to 5 V, as in the case of the start of the operation of the microcomputer 20. As a result, the voltage of the DC output unit 11 becomes 12 V, and a stable voltage necessary for operating the outdoor supply relay 8 and the like is supplied. This mode is the normal operation mode.

  As described above, according to the power supply control device of this embodiment, the output voltage of the switching power supply is reduced by reducing the reference voltage of the error amplifier circuit by the reference voltage changing means during the operation standby mode. With a simple circuit configuration, it is inexpensive, highly accurate and reliable, and power consumption during operation standby can be effectively reduced.

  Further, according to the power supply control device of this embodiment, the error amplifying circuit is configured by the operational amplifier that operates based on the difference between the output voltage of the switching power supply and the reference voltage, and the reference voltage changing means is the reference voltage of the operational amplifier. Since the voltage is changed, it is possible to reduce power consumption during operation standby effectively with a simple circuit configuration, low cost, high accuracy and reliability.

  Further, according to the power supply control device of this embodiment, since the change of the reference voltage is performed by the duty ratio control of the microcomputer output, the output voltage of the switching power supply during operation standby can be set finely and accurately. It becomes possible to reduce the power consumption during standby to the maximum.

  Further, according to the power supply control device of this embodiment, the output voltage of the switching power supply is adjusted until the voltage value detected by the voltage detection means becomes the minimum voltage value at which the signal input circuit including the microcomputer can operate. Since the reference voltage is changed so as to be lowered, the power consumption during operation standby can be reduced to the maximum.

Embodiment 3 FIG.
FIG. 4 shows Embodiment 3 in which the power supply control device according to the present invention is applied to a power supply control device for an indoor unit of an air conditioner. In FIG. 4, parts corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

  In this embodiment, a resistor 40 and a resistor 41 for dividing and detecting the voltage of the DC output unit 11 are added, and a connection point between the resistors 40 and 41 is connected to an analog input terminal of the microcomputer 20. The voltage detection value of the DC output unit 11 is captured.

  When the remote control operation switch or the main body operation switch is pressed in the operation standby state, the microcomputer 20 turns on the transistor 19 by the signal from the remote control reception circuit 21 or the main body operation switch circuit 22, and the reference voltage 2 of the shunt regulator 15 is turned on. In the process of increasing the voltage to 12V which is (24/5) times 5V, the voltage of the DC output unit 11 divided by the resistors 40 and 41 is detected by the microcomputer 20 and stabilized to 12V. After the microcomputer 20 determines that the operation has been performed, the operation of the outdoor power supply relay 8 and the like is started. Thereby, a necessary and stable voltage can be accurately supplied to each part of the device.

  When shifting to the normal operation mode, if the voltage of the DC output unit 11 detected by the microcomputer 20 does not become the specified value (12 V) within the specified time, it is determined that there is an abnormality in the circuit and the normal operation is performed. Without starting, the operation display lamp 10 can be blinked to notify the abnormality.

  As described above, according to the power supply control device of this embodiment, according to the power supply control device of the next invention, the operation command is received by the signal input circuit and the operation standby mode is shifted to the normal operation mode. At this time, after the output voltage detected by the output voltage detection means becomes equal to or higher than the specified value, the drive circuit of each part of the device is started to operate, so that it is possible to reliably operate each part of the device in the minimum necessary time.

  In addition, according to the power supply control device of this embodiment, when the output voltage of the switching power supply detected by the output voltage detection means does not exceed the specified value when shifting from the operation standby mode to the normal operation mode, an abnormality display is displayed. As a result, serviceability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is an electric circuit diagram which shows Embodiment 1 which applied the power supply control apparatus of this invention to the power supply control apparatus for indoor units of an air conditioner. 3 is a flowchart illustrating the operation of the microcomputer in the power supply control device according to the first embodiment. It is an electric circuit diagram which shows Embodiment 2 which applied the power supply control apparatus of this invention to the power supply control apparatus for indoor units of an air conditioner. It is an electric circuit diagram which shows Embodiment 3 which applied the power supply control apparatus of this invention to the power supply control apparatus for indoor units of an air conditioner. It is a block diagram of the conventional power supply control apparatus. It is an electric circuit diagram of a conventional power supply control device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial alternating current power supply 2 Bridge rectifier circuit 3 Switching transformer 4 Converter control part 7 3 terminal regulator 10 Operation display lamp 11 DC output part 14 Photocoupler 15 Shunt regulator 16, 17, 18 Resistance 19 Transistor 20 Microcomputer 21 Remote control receiving circuit 22 Main body Operation switch circuit 23 Drive circuit section 24 Operational amplifier 28, 29, 40, 41 Resistance

Claims (7)

In the power supply control device used in the normal operation mode and the operation standby mode,
A switching power supply that creates a DC power supply for the drive unit of each part of the equipment from an AC commercial power supply,
A power supply for a microcomputer that generates a constant DC voltage for a signal input circuit including a microcomputer by using the DC power supply as an input;
Reference voltage changing means for changing the reference voltage based on the output voltage of the microcomputer power supply;
An error amplification circuit that performs stable voltage control based on the reference voltage output by the reference voltage changing means and the output voltage of the switching power supply;
With
The power supply control device according to claim 1, wherein the reference voltage changing means reduces the reference voltage during an operation standby mode. The error amplifier circuit includes an operational amplifier that operates based on a differential voltage between a divided voltage obtained by dividing the output voltage of the switching power supply and the reference voltage,
The power supply control device according to claim 1, wherein the reference voltage changing unit changes a reference voltage applied to the operational amplifier.   The power supply control device according to claim 2, wherein the output voltage of the switching power supply is controlled by duty ratio control of the reference voltage output.   A first voltage detecting means for detecting a voltage value of the power supply for the microcomputer; and a voltage value detected by the first voltage detecting means is a minimum value at which a signal input circuit including the microcomputer can operate. The power supply control device according to claim 2 or 3, wherein the reference voltage is changed so as to reduce an output voltage of the switching power supply until a voltage value is reached.   The drive circuit of each part of the device is operated after a predetermined time has elapsed after performing the control to switch the output voltage of the switching power supply to the normal voltage when shifting from the operation standby mode to the normal operation mode. Item 5. The power supply control device according to any one of Items 1 to 4.   A second voltage detecting means for detecting the output voltage of the switching power supply, and the output voltage value detected by the second voltage detecting means exceeds a specified value when shifting from the operation standby mode to the normal operation mode; The power supply control device according to any one of claims 1 to 5, wherein the operation of the drive circuit of each part of the device is started after becoming.   The abnormality display is performed when the output voltage of the switching power supply detected by the second voltage detection means does not exceed a specified value when shifting from the operation standby mode to the normal operation mode. Power supply control device.

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