JP2015042011A - Power supply circuit for control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widely effectively utilize a configuration for reducing standby power in a power supply circuit packaged in electrical equipment for more general electrical equipment.SOLUTION: The power supply circuit comprises: a plurality of functional means 2 forming functions of equipment; control means for controlling operations of the functional means 2; a primary power source which becomes a supply source of operational power of the functional means 2 and is stabilized at a specified voltage; a secondary power source which becomes a supply source of operational power of the control means 3; and voltage drop means 4 which is operated by partially consuming power of the primary power source and supplies a further dropped voltage to a load side as the secondary power source. The control means 3 uses the secondary power source as a power source and all the functional means are operated by using the primary power source as power sources. Therefore, since the voltage drop means 4 can be specialized for supplying minimum power required for the control means 3 in spite of a change in the operational power of the functional means 2. Thus, it is not necessary to package a plurality of circuit configurations of the power source and cost can be prevented from being increased with reduction of standby power.

Description

  The present invention provides a control device that reduces the power consumption of a power supply when the load of the power supply output during standby of the equipment is light while supplying a stable voltage drop to the configuration of the control circuit mounted for control in the electrical equipment This relates to the power supply circuit.

  In recent years, a power circuit of a control device mounted on an electric device is generally consumed in a so-called standby state in which the main power source is energized but the electric device is stopped from the viewpoint of power saving. Therefore, there is a need for a circuit configuration of a power source that can reduce power consumed from a main power source known as standby power as much as possible.

  By the way, the main body of the control circuit of the control device responsible for the control of the device mounted on the electric device is a voltage stabilized from 3V to 6V, for example, by a circuit configuration of a high-voltage AC commercial power supply and a step-down stabilization power supply. It is extremely common to use a microcomputer that operates as a power source.

  The microcomputer executes the operation of the device control process by sequentially processing the operation procedure of the device stored in the memory as a program based on the time interval of the specified frequency.

  Further, the microcomputer can process more procedures per unit time as the prescribed frequency for processing the procedure is higher, but the power consumption increases.

  In such a control circuit mainly composed of a microcomputer, when a device is controlled to a normal operation state, when it is controlled to a standby state, it functions as a device mounted on the device to be controlled. Since the operation of the circuit configuration is also stopped, the power consumed from the circuit configuration of the power supply is mainly the power required for the control processing operation of the microcomputer, so that the standby state of the device is minimized.

  For this reason, in order to reduce standby power consumption by reducing the power consumption of the main power source in the standby state, the circuit configuration of the power supply consumed when the control circuit is controlled to the standby state It can be seen that the higher the power conversion efficiency of the circuit configuration of the power supply is, the more advantageous in the state of supplying the minimum amount of power that is a light load.

  However, the circuit configuration of the power supply has the highest power conversion efficiency in order to suppress the heat generation of the circuit configuration in a state where more power supply is required on the load side in the normal operation state of the device. It is necessary to design to.

  Therefore, it is usually difficult to reduce standby power more than a certain amount due to the basic configuration of the power supply circuit because the self-power consumption required for power conversion increases with respect to the power supplied to the output side at light load. Therefore, there is a need for a circuit configuration of a power source that can improve this point and further reduce standby power.

  Conventionally, as a power supply circuit of a control device that can cope with this type of problem, a low-voltage power stabilized by a high-voltage power supply source on the main power source side is converted and supplied to the power load of the control circuit. As a circuit configuration of the power supply, the efficiency is high when the equipment is in a normal operation state and a large amount of power supply is required on the load side, for example, a switching regulator and the minimum power supply to the load side in the standby state By having two configurations of a series regulator that enables efficient power supply when required, by stopping the operation of the switching regulator in the standby state and supplying power only from the series regulator to the load side, A configuration is known in which standby power consumed from the main power source is further reduced (see, for example, Patent Document 1).

  Hereinafter, the power supply circuit of the control device will be described with reference to FIG.

  As shown in FIG. 3, the input voltage supplied from the input terminal 100 side is converted into a predetermined output voltage, and power is supplied from the output terminal 101 to the load side. High efficiency when the power consumption on the load side is high The first circuit 102 composed of a switching regulator capable of performing power conversion of the above and the power input on the load side that inputs the input voltage and controls the output voltage so that its own output voltage becomes a predetermined voltage. And a series regulator 103 that can perform high-efficiency power conversion at low times.

  In the above configuration, when the output load required for the power source is large, the first circuit 102 is operated, and when the load is small, the operation of the first circuit 102 is stopped and the series regulator 103 outputs the output terminal. In the standby state of the device, the standby power is reduced by supplying power to the load side only from the series regulator 103 which is highly efficient when the supply power is low. .

Japanese Patent No. 3509806

  In such a power supply circuit of a conventional control device, the operation of the first circuit 102 is stopped when only a minimum power supply is required on the load side because the control circuit controls the device to a standby state. Since power is supplied from the series regulator 103 to the output terminal 101, standby power is reduced by supplying power to the load side only from the series regulator 103, which is highly efficient when the supplied power is low. It was.

  From this, the first circuit 102 is used to further reduce the standby power when the control circuit controls a device that requires only a minimum power supply to the load side with respect to the circuit configuration of the power supply. And two types of series regulators 103 were necessary as a circuit configuration of the power source.

  Therefore, in order to stably supply power to the control circuit, it is necessary to mount a plurality (two or more types) of the conventional configuration corresponding to only one power source circuit configuration, which causes an increase in cost. Therefore, there is a problem that hinders widespread use in general electrical equipment.

  Therefore, the present invention solves the above-described conventional problems, and provides a power supply circuit for a control device that can be more widely used in general electrical equipment by suppressing an increase in cost associated with a reduction in standby power. The purpose is to do.

  In order to achieve this object, the present invention provides a primary power source stabilized at a specified voltage as a main power supply source mounted on an electrical device, and the primary power source as an input. A voltage step-down means that further lowers the voltage by consuming part and converts the voltage and operating power required on the load side as a secondary power source and outputs it, and one or more operating with a DC power source that functions as a device And a control means for controlling the operation of the functional means by operating with a minimum amount of power in the device, the control means uses a secondary power source as a power source, and all The functional means is configured to operate with a primary power source as a power source, thereby achieving the intended purpose.

  According to the present invention, a primary power supply stabilized to a specified voltage serving as a main power supply source mounted on an electrical device, and the primary power supply as an input, further consuming a part of the power. A voltage step-down means for stepping down a voltage and converting and outputting a voltage and operating power required on the load side as a secondary power source, one or more functional means operating with a DC power source that constitutes the function of the device, and a device And a control means for controlling the operation of the functional means by consuming the minimum power and operating the secondary power supply, and all the functional means are primary power supplies. Since all the functional means operate using the primary power supply as the power source, the voltage step-down means does not need to consider the change in the power supply due to the operating state of the functional means, The control hand Since it can be specialized to supply the minimum power required only for the operation of the secondary power supply as a secondary power supply, it is not necessary to install multiple power supply circuit configurations, suppressing the increase in cost associated with the reduction of standby power Therefore, it is possible to obtain an effect that a power supply circuit of a control device that can be easily used widely in general electric equipment can be provided.

1 is a block diagram showing a schematic circuit configuration of a power supply circuit according to a first embodiment of the present invention. A schematic circuit diagram showing a part of the power supply circuit. Circuit diagram showing configuration of power supply circuit of conventional control device

  A power supply circuit of a control device according to claim 1 of the present invention includes a primary power supply stabilized to a specified voltage that is a main power supply source mounted on an electric device, and the primary power supply as an input. The voltage is stepped down by consuming a part of the voltage and the voltage and operating power required on the load side are converted and output as a secondary power source, and one operating with a DC power source that functions as a device. In the configuration including the functional means described above and a control means for controlling the operation of the functional means by operating with a minimum power consumption in the device, the control means uses a secondary power source as a power source, and All the functional means are configured to operate using a primary power source as a power source. As a result, since all the functional means operate using the primary power supply as a power source, the voltage step-down means is not required to consider a change in power supply due to the operating state of the functional means, and is necessary only for the operation of the control means. Since it is possible to specialize in supplying the minimum power required as a secondary power supply, it is not necessary to install multiple power supply circuit configurations, and the increase in cost associated with reduction in standby power can be suppressed. There is an effect that it is possible to provide a power supply circuit of a control device that is easy to use widely in general electrical equipment.

  The control means has a microcomputer as a main component, and the microcomputer can switch a reference frequency itself for the control process in the control process, and the reference frequency is set to a low frequency. The power consumption can be reduced by switching to the side, and the reference frequency may be set to the low frequency side within a range that does not hinder the control processing. As a result, the power consumption required for the control process can be reduced by setting the reference frequency to the low frequency side within a range that does not hinder the control process required for the function control of the device, and thus the voltage step-down means is required. Since the power capacity of the power supply can be reduced, a circuit configuration of a power supply that is lower in cost can be used, so that an increase in cost associated with a reduction in standby power can be further suppressed. There is an effect that it is possible to provide a power supply circuit of a control device that is easy to use widely.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows an outline of a configuration of a control circuit mounted on an electric device having a control function.

  In the figure, a dashed box indicates an outer shell 1 that is a main body of the device.

  A plurality of functional means 2 (shown as one configuration in the figure) forming the function of the device inside the outer shell 1 and a control means 3 for controlling the operation of the functional means 2 by a voltage signal are provided. .

  Further, a primary power source stabilized to a specified voltage indicated by V1 in the figure, which is a power supply source for the operation of the functional unit 2, and a power supply for the operation of the control unit 3 A secondary power source is provided which is stabilized to the required specified voltage indicated by V2 in the figure.

  Further, in order to supply the secondary power supply, a voltage step-down means 4 that operates by partially consuming the power of the primary power supply and outputs a further stepped down voltage to the load side is provided.

  Further, each functional means 2 is controlled so that the operation of each functional means 2 on the high voltage side with the load of the primary power supply can be controlled by a voltage signal from the control means 3 on the low voltage side with the load of the secondary power supply. Accordingly, signal potential conversion means 5 is provided between the control means 3 and the control means 3.

  Here, the primary power supply does not define a specific configuration for its generation, and any configuration can be used as long as it can stably supply the voltage and power required on the load side.

  For example, after AC voltage is rectified using an AC high-voltage commercial power supply as a power supply source, an intermittent current is conducted on the primary side of the transformer to generate a stepped down voltage on the secondary side of the transformer, and then rectified. A so-called switching regulator configuration that stabilizes the output voltage to a specified voltage value by changing the intermittent period and interval by obtaining a DC voltage and feeding back the DC voltage value and comparing it with a reference voltage. May be used.

  Alternatively, it may be an output of a storage battery such as a battery that supplies electric power for a certain time to a load side at a specified voltage by storing electric charge.

  Further, although the voltage of the primary power supply is not specified, it is typically around 15 V in many general electric devices such as air conditioners.

  Here, the functional means 2 constitutes a main function of the device. As an example, a DC motor that operates by consuming a relatively large amount of power as a driving force source of a blower in an air conditioner or the like, A DC motor driving IC or a driving power that requires a voltage higher than that required for the control means 3 is shown.

  Alternatively, a function that operates by consuming relatively small power such as a display device such as an LED or a sounding device such as a buzzer that performs a specific function when the state is changed by a voltage signal as a control target of the control unit 3 Although an element is shown, since it is not related to the gist of the present embodiment, a detailed description is omitted.

  Here, the control means 3 is mainly composed of a so-called one-chip microcomputer.

  This microcomputer has a central processing unit that performs calculation and judgment processing, an input / output terminal that can capture and output an external voltage change signal, an A / D input terminal that can convert an analog voltage signal into a digital value, The read-only memory for storing the operation procedure as software and the random access memory for temporarily storing the calculation and determination state are integrated.

  In addition, a series of control processing procedures are stored as a software description program on a read-only memory, and these procedures are sequentially executed based on a so-called clock signal time interval at a fixed reference frequency. Thus, the control operation of the device can be independently processed and executed.

  In addition, the basic specification is that the input / output terminal provided in the microcomputer is in a state in which current input / output is not performed as a high resistance state if the power supply voltage is equal to or lower than the startup voltage and the control processing operation is stopped. It is general that it is.

  Therefore, after the power supply changes to the start voltage or higher, the Hi potential that becomes the power supply potential or the Lo potential that becomes the reference potential (GND) based on the internal processing based on the software description stored in the read-only memory, or the high potential The state is selected as the resistance state input terminal.

  The power consumed in this microcomputer usually increases for programs that require more procedure processing per unit time, and more procedures can be processed per unit time as the frequency of the clock signal increases. Although possible, power consumption will increase.

  In recent years, a clock signal whose frequency can be switched in a control process by a program has been generalized.

  Therefore, by using this switchable frequency, the power consumption can be further reduced by switching the clock signal in the low frequency direction as long as there is no delay in the control processing required per short time. ing.

  In such microcomputers that are standard in many electric devices, the power consumption depends on the frequency of the clock signal, but if the power supply voltage is 5 V, for example, a comparison is possible. In particular, when the procedural process per unit time is a high load, a current of around 3 mA is required, so that about 15 mW is consumed.

  In addition, if the procedural process per unit time is a low load, a current of around 1 mA is required, so the power consumption is about 5 mW.

  Furthermore, when the procedure processing per unit time is low and the clock signal can be switched in the low frequency direction, the current can be reduced to around 0.5 mA, so that the power consumption can be reduced to about 2.5 mW.

  Note that the control processing required when the microcomputer is controlled to the standby state with respect to the state where the device is controlled to the normal operating state is the waiting for the state transition trigger signal input from the outside to the input terminal. In general, it is in the order of acceptance (such as a switch operation by the user for transition from the standby state to the normal operation state).

  Therefore, when the device is controlled to be in the standby state, the number of processes in the calculation process and the determination procedure in the control process is usually the lowest, so the power consumption is also the lowest. For example, as described above, the device is put in the normal operation state. If about 15 mW is consumed during the control, about 5 mW of power is consumed in the standby state.

  Furthermore, if the clock signal can be switched in the low frequency direction, it can be reduced to about 2.5 mW.

  In addition to the microcomputer, the functional means 2 includes, for example, a reset circuit that supplies an initialization voltage signal in the normal operating voltage range to the control means 3, and a pull-up or pull-down resistance element for reducing impedance of the input / output terminals. The minimum configuration required for the operation of the control process is included.

  In addition, it is necessary when the equipment is on standby, for example, a sensor circuit such as temperature / humidity detection for grasping the ambient environment and the state of equipment operation, a remote control operation signal receiving circuit for performing a remote operation function, etc. In addition, it includes a configuration that is required at a minimum for the operation of the control processing that requires only several mA or less of the same power as the microcomputer for the operation.

  However, in general, the minimum configuration required for the operation of the microcomputer is a resistance element such as pull-up or pull-down, which basically does not pass current, or a reset circuit of several μ to several mA. Since it operates with a small amount of current, it does not substantially affect the magnitude of power consumption with respect to the main power supply, so it is not shown in the drawing and will not be described in detail.

  Note that when the device is controlled to be in a standby state, the repetition of the constant process with few branches is generally the main part of the control process, so the power consumption is also made constant with almost no fluctuation.

  In addition, since each functional means 2 is also in the standby state of the device by the control processing of the control means 3, it is not necessary to perform active operations (motor operation, steady buzzer sound, LED lighting, etc.). Therefore, no power consumption occurs in the standby state.

  Here, the voltage step-down means 4 is a voltage that is regulated by lowering the voltage from the primary power supply in a standby state where the control means 3 on the load side is required to supply a minimum amount of operating power. The secondary power source is generated.

  For this reason, the voltage step-down means 4 is, for example, in the case of supplying low power to the load side, by reducing its own power consumption accompanying a low voltage drop operation, It is suitable to use a discrete circuit generally composed of a plurality of circuit elements or a series regulator composed of integrated circuit elements in which the same structure is made into one chip, which has a feature that voltage can be converted efficiently compared to the above. .

  In general, in the circuit configuration of the power source, including the configuration of the series regulator, it is necessary to use a component having a higher power durability performance as the supply power required on the output side is larger.

  Here, in general, circuit elements become more expensive as they have better power handling performance, and additional heat radiators may be required to suppress temperature rise due to heating of conduction power, which increases the cost of circuit configuration. Will be invited.

  Therefore, the smaller the required power supply, the more advantageous it is to reduce the cost. Therefore, in the microcomputer which is the control means 3 serving as the load of the voltage step-down means 4, the operation reference frequency is switched. As described above, as long as there is no delay in the control processing required for a short period of time using what is possible, the power consumption is reduced as much as possible by switching to the low frequency direction. It is.

  The voltage step-down means 4 does not define the application of a series regulator, and a switching regulator configuration may be used.

  Note that when the control means 3 can be regarded as equivalent to a resistive load that consumes a substantially constant current from the secondary power supply without greatly changing power consumption in all control operations from the standby state to the normal operation state, this equivalent A voltage dividing resistor that divides a voltage within a range allowed by the control means 3 to generate a voltage as a secondary power supply at both ends of the control means 3 when the current from the primary power supply is conducted in series with a resistance load. The body can also be used as the voltage step-down means 4.

  In the actual application of this voltage dividing resistor, as described above, for example, the primary power supply is 15 V and the secondary power supply is a specified voltage of 5 V, and the power consumption of the control means 3 when controlling the device in the standby state is as follows. If it is 10 mW, the control means 3 can be regarded as equivalent to a 2.5 kΩ equivalent resistance value, so that a resistance value of 5 kΩ and a power durability of 20 mW or more can be used.

  Further, if the power consumption by lowering the frequency of the clock signal in the control means 3 becomes 7.5 mW, it can be regarded as equivalent to an equivalent resistance value of 3.3 kΩ, so that the resistance value has a power durability performance of 6.7 kΩ. It is possible to use a very small resistance element having a smaller rated power, which is 15 mW or more.

  In this way, a resistive element that has a small rated power and a small size can be applied to the voltage dividing resistor, and such a small resistive element is a general-purpose product and is used most often among circuit elements that are generally used. Since the amount of circulation is large, it is advantageous that it is relatively inexpensive and easily available among various circuit elements.

  In the case of a series regulator, the power consumption of about 1 mW to 10 mW is required for the circuit operation itself of the low voltage drop. However, if the voltage dividing resistor is used, only the power consumption due to the voltage drop is generated. Consumption can be further reduced.

  Here, the signal potential converting means 5 is, for example, a transistor which is an element capable of switching current conduction of 100 times or more on the output side where the potential becomes high with respect to the input current as shown in FIG. The element 6 is configured.

  FIG. 2 is a schematic diagram showing only one target functional unit 2, a control unit 3 that is a microcomputer, and a signal potential conversion unit 5 for switching the current conduction of the target functional unit 2. It is a circuit diagram.

  Here, the target functional means 2 will be described by taking the LED element 7 as an example, which is a display element for notifying the control state by a change in the light emission state by emitting light by current conduction. .

  In the configuration of the signal potential converting means 5, there is a restriction for limiting the base current to a necessary prescribed value or less between the output terminal 3 a of the microcomputer constituting the control means 3 and the base terminal of the NPN transistor element 6. A resistor 8a is arranged, the anode terminal of the LED element 7 is connected to the positive side of the primary power supply, and a limiting resistor 8b for restricting the conduction current to the LED to a specified value or less is arranged at the cathode terminal, thereby providing a transistor element. 6 connected to the collector terminal.

  Here, the transistor element 6 is not specially defined as long as the current conduction between the collector and emitter terminals can be switched. Therefore, a general low-speed switch switching transistor element that is inexpensive and highly available is used. be able to.

  Further, the limiting resistor 8a is an element for conducting a current that causes the transistor element 6 to enter a conducting state when a voltage of the secondary power source output from the output terminal 3a of the control means 3 is applied. However, a transistor is an element that can switch the conduction of a current that is generally 100 times or more of the input current, and since the object of the transistor element 6 that is switched on is a very small current as described above, it has a high resistance value. Can be used.

  Therefore, if the Lo potential is being output from the output terminal 3a of the control means 3, the base current does not flow through the limiting resistor 8a. Therefore, the collector and emitter of the transistor element 6 are in an open state, the current from the primary power supply does not flow to the LED element 7 via the limiting resistor 8b, and the LED element 7 can be kept in the extinguished state.

  Further, if the Hi potential is being output from the output terminal 3a of the control means 3, the base current flows through the limiting resistor 8a, so that the collector and emitter terminals of the transistor element 6 are in a conductive state, and the limiting is performed. The current from the primary power source flows to the LED element 7 through the resistor 8b, and the LED element 7 changes to a lighting state.

  Even if the LED element 7 is designed to require a relatively large current of about 100 mA, the base current of the transistor element 6 may be about 1/100 times as described above. A current of about 1 mA may be output from the terminal 3a.

  From this, when the voltage of the secondary power source is 5V, switching of the LED element 7 which is the functional means 2 can be controlled to be switched off and on with or without a minute power consumption of about 5 mW.

  Therefore, the signal potential converting means 5 is required to be able to control the switching of the conduction current required for the functional means 2 to be controlled by the output of the lowest current from the output terminal 3a, and this condition is met in practical use. As long as it is a thing, you may use not only the transistor element 6 but suitable elements, such as a field effect transistor and a dedicated gate device IC.

  According to such a configuration, all the functional means 2 are configured to operate using the primary power supply as a power source. Therefore, in the voltage step-down means 4, it is not necessary to consider the change in supplied power due to the operating state of the functional means 2, and the control is performed. It can be specialized to supply the minimum power required for only the operation of the means 3 as a secondary power source.

  Accordingly, it is not necessary to mount a plurality of circuit configurations of the power source, and an increase in cost associated with a reduction in standby power can be suppressed, so that it can be easily used in general electric devices.

  In addition, the functional means 2 for the equipment uses a microcomputer as a main component and can reduce the power consumption required for the control processing by setting the reference frequency to the low frequency side within a range that does not hinder the control processing. Therefore, the power capacity required for the voltage step-down means 4 can be further reduced.

  Therefore, since it is possible to use a circuit configuration of a power supply that is lower in cost, it is possible to further suppress an increase in cost due to a reduction in standby power, and thus to make it easier to use widely in general electrical equipment. it can.

  The power supply circuit of the control device according to the present invention has a configuration capable of reducing power consumption when the device is on standby while suppressing a factor of cost increase with respect to the configuration of the control circuit mounted for control in the electrical device. Therefore, it is useful as a power supply circuit for a control device that can be widely installed in general electrical equipment and electrical devices in general.

2 Function means 3 Control means 4 Voltage step-down means

Claims (2)

A primary power supply stabilized to a specified voltage to be a main power supply source mounted on an electrical device;
Voltage step-down means for taking the primary power supply as input and further reducing the voltage by consuming a part of the power, converting the voltage and operating power required on the load side as a secondary power supply, and outputting;
One or more functional means that operate with a DC power source that functions as a device;
In a configuration comprising control means for controlling the operation of the functional means by operating with a minimum power consumption in the device,
A power supply circuit for a control device, wherein the control means operates using a secondary power supply as a power supply, and all the functional means operate using a primary power supply as a power supply. The control means has a microcomputer as a main component,
The microcomputer can switch the reference frequency itself for the control process in the control process, and can reduce its own power consumption by switching the reference frequency to the low frequency side. The control circuit power supply circuit according to claim 1, wherein the reference frequency is set on the low frequency side within a range that does not interfere with control processing.

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