JP2023080723A - Power supply control circuit - Google Patents

Abstract

To provide a power supply control circuit which can reduce power consumption.SOLUTION: When an operation switch 11 is turned on, a switching element 13 is brought into an ON-state so that an ON-signal is inputted to an enable terminal 20. As a result, a DC-DC converter 12 starts supplying a predetermined voltage V2 to a microcomputer 3. When the operation switch 11 is turned off, the switching element 13 is brought into an OFF-state so that an OFF-signal is inputted to the enable terminal 20. As a result, the DC-DC converter 12 stops supplying the predetermined voltage V2 to the microcomputer 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power control circuit that controls the supply of driving power from a battery to a load circuit.

In a plant or the like having a steam piping system, condensate (drainage) may occur in the piping system due to heat exchange or heat radiation. If this condensate stays in the piping system, it will cause a decrease in operating efficiency. I have to.

If the sealing performance of the steam trap is impaired due to aged deterioration, malfunction, or the like, steam in the steam piping system leaks to the outside through the steam trap, resulting in unnecessary steam loss. Therefore, the operation of checking the state of the steam trap is performed periodically, such as once a year.

Patent Literature 1 listed below discloses a measuring device and a diagnostic device for diagnosing the state of a steam trap. The measuring device is a portable measuring device, the diagnostic device is a tablet terminal, a laptop computer, or the like, and wireless communication is possible between the measuring device and the diagnostic device. The measuring device includes a temperature sensor that measures the surface temperature of each steam trap, a vibration sensor that measures the vibration intensity of each steam trap, a storage unit that stores measurement data output from the temperature sensor and the vibration sensor, and the measurement A communication unit for transmitting data to the diagnostic device and a display unit are provided. The diagnostic device diagnoses the state (normal or abnormal) of each steam trap based on the measurement data received from the measurement device, and transmits diagnostic data indicating the result of the diagnosis to the measurement device. Based on the diagnostic data received from the diagnostic device, the measuring device displays the diagnostic result of each steam trap on the display unit.

FIG. 5 is a circuit diagram showing a simplified part of the circuit configuration of the measuring device according to the background art. The measuring device includes a battery 102 such as an alkaline dry battery, a microcontroller (hereinafter abbreviated as “microcomputer”) 103 , and a power control circuit 101 that controls supply of drive power from the battery 102 to the microcomputer 103 . The power control circuit 101 has a DC/DC converter 111 , a resistance element 112 and an operation switch 113 . The microcomputer 103 has a power port 121 and an input port 122 . Power supply port 121 is connected to node N51 between DC/DC converter 111 and resistance element 112 . Input port 122 is connected to node N52 between resistance element 112 and operation switch 113 . The DC/DC converter 111 supplies a predetermined voltage obtained by stepping up or stepping down the output voltage from the battery 102 to the power port 121 of the microcomputer 103 as a drive power source.

The microcomputer 103 has sleep mode and active mode as its operation modes. The sleep mode is a mode for reducing power consumption by restricting valid functions among all the functions of the microcomputer 103 . Active mode is a mode in which all functions of the microcomputer 103 are enabled.

When the user turns on the operation switch 113 while the microcomputer 103 is in the sleep mode, the microcomputer 103 detects the execution of the on operation by a change in the input voltage value to the input port 122, and returns itself from the sleep mode to the active mode. do. A drive power supply for the microcomputer 103 in the active mode is supplied from the DC/DC converter 111 to the power supply port 121 .

When the user turns off the operation switch 113 while the microcomputer 103 is in the active mode, the microcomputer 103 detects the execution of the off operation by the change in the input voltage value to the input port 122, and shifts itself from the active mode to the sleep mode. do. The drive power for the microcomputer 103 in the sleep mode is supplied from the DC/DC converter 111 to the power port 121 as in the active mode.

JP 2018-84418 A

In the measuring device according to the background art, power for driving the microcomputer 103 in sleep mode is supplied from the DC/DC converter 111 to the power port 121 . That is, the DC/DC converter 111 is driven even in the sleep mode. The DC/DC converter 111 consumes a relatively large amount of current (on the order of several mA) due to conversion loss and the like. Therefore, in the measuring device according to the background art, the consumption of the remaining capacity of the battery 102 is large even in the sleep mode. could become.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power supply control circuit capable of reducing power consumption.

A power control circuit according to one aspect of the present invention is a power control circuit that controls the supply of drive power from a battery to a load circuit, and has an operation switch that is turned on or off by a user, and an enable terminal. a voltage conversion circuit for supplying a predetermined voltage obtained by stepping up or stepping down the output voltage from the battery to the load circuit as the drive power supply; and a switching element connected to the enable terminal, wherein the operation switch is turned on. By being operated, the switching element is turned on and an ON signal is input to the enable terminal, whereby the voltage conversion circuit starts supplying the predetermined voltage to the load circuit, and the operation switch is turned on. By being turned off, the switching element is turned off and an off signal is input to the enable terminal, whereby the voltage conversion circuit stops supplying the predetermined voltage to the load circuit.

According to this aspect, when the operation switch is turned off, the switching element is turned off and an off signal is input to the enable terminal, whereby the voltage conversion circuit stops supplying the predetermined voltage to the load circuit. . As a result, it is possible to stop driving the voltage conversion circuit, which consumes a relatively large amount of power, so that the amount of power consumed by the power supply control circuit can be reduced.

The above aspect further includes a holding circuit, wherein the load circuit has a first input port, and the holding circuit holds the ON state of the switching element based on the predetermined voltage output from the voltage conversion circuit. After generating a hold voltage for the load circuit, inputting the hold voltage to the first input port, and turning on the operation switch, the voltage conversion circuit starts supplying the predetermined voltage to the load circuit, A portion of the output current from the battery is input to the first input port to keep the switching element on.

According to this aspect, the ON state of the switching element is continued by the operation of the holding circuit, so that the supply of the predetermined voltage from the voltage conversion circuit to the load circuit can be appropriately continued.

In the above aspect, the load circuit has a second input port, and after the voltage conversion circuit stops supplying the predetermined voltage to the load circuit by turning off the operation switch, the output current from the battery is input to the second input port.

According to this aspect, even after the supply of the predetermined voltage from the voltage conversion circuit to the load circuit is stopped, it is possible to supply the minimum required driving power from the battery to the second input port of the load circuit.

In the above aspect, the load circuit has a third input port to which a monitor voltage corresponding to the voltage value of the output voltage from the battery is input regardless of whether the switching element is in an ON state or an OFF state. have

According to this aspect, regardless of whether the switching element is in the ON state or the OFF state, the remaining capacity of the battery can be easily managed by the monitor voltage input to the third input port.

In the above aspect, the load circuit includes a control circuit provided in a portable measuring device for diagnosing a steam trap.

According to this aspect, the power consumption of the portable measuring device for diagnosing the steam trap can be reduced.

According to the present invention, power consumption can be reduced.

1 is a circuit diagram showing a simplified part of a circuit configuration of a measuring device according to an embodiment of the present invention; FIG. 4 is a circuit diagram showing the operation of the power control circuit; FIG. 4 is a circuit diagram showing the operation of the power control circuit; FIG. 4 is a circuit diagram showing the operation of the power control circuit; FIG. It is a circuit diagram which simplifies and shows a part of circuit structure with which the measuring device which concerns on background art is provided.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Elements with the same reference numerals in different drawings represent the same or corresponding elements.

FIG. 1 is a circuit diagram showing a simplified part of the circuit configuration of a measuring device according to an embodiment of the present invention. A measuring device is a portable measuring device for diagnosing a steam trap. When an operator presses a probe of the measuring device against the steam trap to be diagnosed, the measuring device measures the temperature and vibration of the steam trap. The measuring device may have a diagnostic function for diagnosing the state (normal or abnormal) of the steam trap based on the measured temperature and vibration. Alternatively, the diagnostic function may be provided in a diagnostic device that can communicate with the measuring device.

Referring to FIG. 1, the measuring device controls the supply of drive power from the battery 2 such as an alkaline battery, a load circuit including a microcontroller (hereinafter abbreviated as "microcomputer") 3, and the microcomputer 3 from the battery 2. and a power supply control circuit 1 . A microcomputer 3 as a control circuit for controlling the operation of the measuring device includes an arithmetic device such as a CPU and a storage device such as a ROM or a RAM. The load circuit may include peripheral circuits and analog circuits in addition to the microcomputer 3 .

The power supply control circuit 1 has a DC/DC converter 12 , resistance elements 14 , 15 , 17 , 21 and 22 , diodes 16 and 18 , a switching element 13 and an operation switch 11 . The DC/DC converter 12 has an enable terminal 20 . The microcomputer 3 has a power port 30 , a first input port 31 , a second input port 32 and a third input port 33 .

In this example, switching element 13 is an N-channel MOSFET and has a gate connected to node N 2 , a drain connected to node N 4 , and a source connected to enable terminal 20 . Node N2 is connected to node N1 and node N3.

The negative electrode of battery 2 is connected to GND, and the positive electrode of battery 2 is connected to node N1. The input of DC/DC converter 12 is connected to node N1, and the output of DC/DC converter 12 is connected to node N6. One end of resistance element 14 is connected to node N3, and the other end of resistance element 14 is connected to node N4. One end of resistance element 15 is connected to node N4 and the other end of resistance element 15 is connected to the anode of diode 16 . The cathode of diode 16 is connected to node N5. Node N5 is connected to node N7.

One end of resistance element 17 is connected to node N6 and the other end of resistance element 17 is connected to the anode of diode 18 . The cathode of diode 18 is connected to node N7. Resistive element 17 and diode 18 constitute a holding circuit.

One end of resistance element 21 is connected to node N3, and the other end of resistance element 21 is connected to node N8. One end of the resistance element 22 is connected to the node N8, and the other end of the resistance element 22 is connected to GND.

One end of the operation switch 11 is connected to the node N5, and the other end of the operation switch 11 is connected to GND.

The power port 30 is connected to the node N6, the first input port 31 is connected to the node N7, the second input port 32 is connected to the node N4, and the third input port 33 is connected to the node N8. It is

A monitor voltage corresponding to the voltage value of the output voltage from the battery 2 is input to the third input port 33 regardless of whether the switching element 13 is in the ON state or the OFF state. The voltage value of the monitor voltage is obtained as a voltage value obtained by dividing the voltage value of the output voltage from the battery 2 by the ratio of the resistance values of the resistance elements 21 and 22 . The microcomputer 3 can easily manage the remaining capacity of the battery 2 based on the monitor voltage input to the third input port 33 regardless of whether the switching element 13 is on or off. The microcomputer 3 outputs an alert prompting the user to replace the battery 2 when, for example, the voltage value of the monitor voltage becomes less than a threshold value slightly larger than the minimum voltage value at which the microcomputer 3 can be driven.

The microcomputer 3 has sleep mode and active mode as its operation modes. The sleep mode is a mode for reducing power consumption by restricting effective functions among all functions of the microcomputer 3 . Active mode is a mode in which all functions of the microcomputer 3 are enabled.

When the microcomputer 3 is in the active mode, the DC/DC converter 12 supplies a predetermined voltage obtained by stepping up or stepping down the output voltage from the battery 2 to the power port 30 of the microcomputer 3 as a drive power source. When the microcomputer 3 is in sleep mode, the DC/DC converter 12 stops driving, and the supply of the predetermined voltage from the DC/DC converter 12 to the microcomputer 3 is stopped.

2 to 4 are circuit diagrams showing the operation of the power supply control circuit 1. FIG. FIG. 2 shows the operation when the user turns on the operation switch 11 while the microcomputer 3 is in the sleep mode. FIG. 3 shows the operation while the microcomputer 3 continues the active mode. FIG. 4 shows the operation when the user turns off the operation switch 11 while the microcomputer 3 is in the active mode.

Referring to FIG. 2, when the user turns on the operation switch 11 while the microcomputer 3 is in the sleep mode, as indicated by an arrow A1a, the resistance element 14, the resistance element 15, the diode 16, and the operation switch are supplied from the battery 2. 11 in this order, current flows to GND. As a result, the switching element 13 is turned on, and a current is input from the node N4 to the enable terminal 20 as an on signal. Inputting an ON signal to the enable terminal 20 causes the DC/DC converter 12 to start driving. The DC/DC converter 12 supplies the power supply port 30 of the microcomputer 3 with a predetermined voltage V2 obtained by stepping up or stepping down the output voltage V1 from the battery 2 .

As described above, resistive element 17 and diode 18 form a holding circuit. When the supply of the predetermined voltage V2 from the DC/DC converter 12 to the power supply port 30 is started, part of the output current from the DC/DC converter 12 flows through the resistance element 17 and the diode 18 as indicated by the arrow A1b. Through this order, it flows to the first input port 31 of the microcomputer 3 . The holding circuit generates a holding voltage for holding the ON state of the switching element 13 as a voltage value after the voltage value of the predetermined voltage V2 is dropped by the resistance element 17 and the diode 18 . The holding voltage is input to the first input port 31 . The holding circuit self-holds the holding voltage of the first input port 31 even after the user releases the operation switch 11 . This completes the booting process of the microcomputer 3, that is, returning from the sleep mode to the active mode.

Referring to FIG. 3, while the microcomputer 3 continues in the active mode, part of the output current from the battery 2 flows through the resistance element 14, the resistance element 15, and the diode 16 as indicated by arrow A2. Through this order, it flows to the first input port 31 of the microcomputer 3 . Since the first input port 31 holds a holding voltage for holding the ON state of the switching element 13, the ON state of the switching element 13 is continued by the current flowing along the path indicated by the arrow A2, and the enable terminal The input of the ON signal to 20 is also continued, and the supply of drive power from the DC/DC converter 12 to the power supply port 30 is also continued.

Referring to FIG. 4, when the user turns off the operation switch 11 while the microcomputer 3 is in the active mode, the microcomputer 3 detects the execution of the off operation from the change in the input voltage value to the first input port 31, Moves itself from active mode to sleep mode. In sleep mode, the holding circuit stops holding the holding voltage at the first input port 31 . As a result, the switching element 13 is turned off by stopping the current in the path indicated by the arrow A2 in FIG. The supply of driving power from the DC/DC converter 12 to the power port 30 is also stopped. After the supply of drive power from the DC/DC converter 12 to the power supply port 30 is stopped by turning off the operation switch 11, the minimum required drive power for executing the sleep mode is supplied as indicated by an arrow A3. , is supplied from the battery 2 to the second input port 32 via the resistive element 14 . The drive power supply in the sleep mode corresponds to a current consumption of several μA to several tens of μA, which is sufficiently smaller than the current consumption of several mA in the active mode.

According to the power supply control circuit 1 according to the present embodiment, when the operation switch 11 is turned off, the switching element 13 is turned off and an off signal is input to the enable terminal 20, thereby turning off the DC/DC converter. 12 (voltage conversion circuit) stops supplying the predetermined voltage V2 to the microcomputer 3 . As a result, the driving of the DC/DC converter 12, which consumes a relatively large amount of power, can be stopped, so that the amount of power consumed by the power supply control circuit 1 can be reduced.

Further, according to the power supply control circuit 1 according to the present embodiment, the supply of the predetermined voltage V2 from the DC/DC converter 12 to the microcomputer 3 is stopped by keeping the switching element 13 in the ON state by the operation of the holding circuit. can be continued appropriately.

Further, according to the power supply control circuit 1 according to the present embodiment, even after the supply of the predetermined voltage V2 from the DC/DC converter 12 to the microcomputer 3 is stopped, the voltage from the battery 2 to the second input port 32 of the microcomputer 3 remains unchanged. It is possible to supply the minimum required driving power.

Further, according to the power supply control circuit 1 according to the present embodiment, the remaining capacity of the battery 2 is determined by the monitor voltage input to the third input port 33 regardless of whether the switching element 13 is in the ON state or the OFF state. can be easily managed.

Moreover, according to the power supply control circuit 1 according to the present embodiment, it is possible to reduce the power consumption of a portable measuring device for diagnosing a steam trap.

REFERENCE SIGNS LIST 1 power control circuit 2 battery 3 microcomputer 12 DC/DC converter 13 switching element 17 resistance element 18 diode 20 enable terminal 31 first input port 32 second input port 33 third input port

Claims (5)

A power supply control circuit for controlling supply of drive power from a battery to a load circuit,
an operation switch that is turned on or off by a user;
a voltage conversion circuit having an enable terminal and supplying a predetermined voltage obtained by stepping up or stepping down the output voltage from the battery to the load circuit as the drive power supply;
a switching element connected to the enable terminal;
with
When the operation switch is turned on, the switching element is turned on and an on signal is input to the enable terminal, whereby the voltage conversion circuit starts supplying the predetermined voltage to the load circuit. ,
When the operation switch is turned off, the switching element is turned off and an off signal is input to the enable terminal, whereby the voltage conversion circuit stops supplying the predetermined voltage to the load circuit. , the power control circuit. further comprising a holding circuit,
the load circuit has a first input port;
the holding circuit generates a holding voltage for holding the ON state of the switching element based on the predetermined voltage output from the voltage conversion circuit, and inputs the holding voltage to the first input port;
After the voltage conversion circuit starts supplying the predetermined voltage to the load circuit by turning on the operation switch, a part of the output current from the battery is input to the first input port, 2. The power control circuit according to claim 1, wherein said switching element is kept on. the load circuit has a second input port;
3. An output current from the battery is input to the second input port after the voltage conversion circuit stops supplying the predetermined voltage to the load circuit by turning off the operation switch. The power control circuit described in . The load circuit has a third input port to which a monitor voltage corresponding to the voltage value of the output voltage from the battery is input regardless of whether the switching element is in an ON state or an OFF state. 4. The power supply control circuit according to any one of items 1 to 3. The power supply control circuit according to any one of claims 1 to 4, wherein the load circuit includes a control circuit provided in a portable measuring device for diagnosing a steam trap.

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