JP2019110629A - Power storage circuit - Google Patents

Abstract

To provide a power storage circuit capable of supplying power to a load with a sufficient voltage even when a power supply starts generating the power in a state of an empty capacitor.SOLUTION: A power storage circuit 10 comprises a capacitor 20 for outputting a supply voltage Vi, a voltage detection circuit 30, a comparison circuit 40, an addition circuit 50, and a switching circuit 60. The voltage detection circuit 30 outputs a reference voltage Vr and a detection voltage Vd. When the capacitor 20 starts to be operated from an empty state, the detection voltage Vd is lower than the reference voltage Vr, and the comparison circuit 40 applies an additionally applied voltage Vxa according to the supply voltage Vi to the addition circuit 50. The switching circuit 60 is connected between the capacitor 20 and a load 88, and connected to the addition circuit 50. An applied voltage Vx lower than a predetermined threshold is applied to the switching circuit 60 until the additionally applied voltage Vxa reaches an additional threshold, and the switching circuit 60 shuts off the load 88 from the capacitor 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a storage circuit that stores minute electric power supplied from a power supply and supplies the electric power to a load.

  For example, Non-Patent Document 1 discloses a storage circuit of this type.

  Referring to FIG. 11, the storage circuit 90 disclosed in Non-Patent Document 1 stores a minute power generated by the power supply 92 by energy harvesting and supplies it to a load 98. The storage circuit 90 includes a power supply line 93, a capacitor (not shown), a voltage detection circuit 94, a comparison circuit 95 (hysteresis comparator), a pull-up resistor 96 formed of a resistor R1, and a switch circuit 97. There is. The capacitor is connected to the power supply line 93, and stores the power generated by the power supply 92. As a result, a voltage Vi is generated on the power supply line 93.

  The voltage detection circuit 94 includes three resistors R5, R10 and R11, and a zener diode Z1. The voltage detection circuit 94 is connected to the power supply line 93, and a voltage Vi is applied to one end of R5 and one end of R10. As a result, a voltage Vr is generated at the other end of R5, and a voltage Vd is generated at the other end of R10. The voltage Vr is the voltage Vi when the voltage Vi is lower than the Zener voltage Vz of Z1, and is the Zener voltage Vz when the voltage Vi is equal to or higher than the Zener voltage Vz. The voltage Vd is a voltage obtained by dividing the voltage Vi by R10 and R11.

  The comparison circuit 95 includes an open drain comparator 952 and two resistors R8 and R9. The comparator 952 is connected to the power supply line 93, and a voltage Vi is applied (not shown). The voltage Vp corresponding to the voltage Vd is applied to the positive input terminal of the comparator 952, and the voltage Vr is applied to the negative input terminal. The output end of the comparator 952 is connected to the power supply line 93 via the pull-up resistor 96 at the connection point 962.

  The switch circuit 97 includes a switching element S1 formed of an N-type MOSFET (metal-oxide-semiconductor field-effect transistor), a switching element S2 formed of a P-type MOSFET, and three resistors R2, R3 and R7. In S1, the source is grounded, the drain is connected to the power supply line 93 through R2 and R3, and the gate is connected to the connection point 962 through R7. In S2, the source is connected to the power supply line 93, the drain is connected to the load 98, and the gate is connected to the drain of S1 via R2.

  With the above-described circuit configuration, when the voltage Vp is lower than the voltage Vr, the connection point 962 (the gate of S1) is grounded and S1 is in the OFF state (the state in which the source and the drain are not conductive). As a result, the voltage Vi is applied to the gate of S2, and S2 is turned off. That is, the switch circuit 97 is in the cutoff state in which the load 88 is disconnected from the capacitor (not shown). On the other hand, when the voltage Vp is equal to or higher than the voltage Vr, the voltage Vi is applied to the gate of S1, and S1 is in the ON state (the state where the source and the drain are conductive). As a result, a voltage smaller than the voltage Vi (a voltage obtained by dividing the voltage Vi by R2 and R3) is applied to the gate of the S2, and the S2 is turned ON. That is, the switch circuit 97 is in a conductive state to make the load 88 conductive with the capacitor.

  According to Non-Patent Document 1, when the power supply 92 generates power while the capacitor (not shown) is empty, the power is gradually stored in the capacitor, and the voltage Vi, the voltage Vd and the voltage Vp gradually increase. . The switch circuit 97 maintains the shutoff state until the voltage Vp reaches the voltage Vr, and the power generated by the power supply 92 is stored in the capacitor without being consumed by the load 98. After the capacitor is sufficiently charged, the voltage Vp becomes equal to or higher than the voltage Vr, and the switch circuit 97 becomes conductive. At this time, a sufficiently large power is supplied to the load 98.

Jin Ono, 3 others, "Development of energy saving and energy harvesting technology applying switching circuit," FY2015 Miyagi Prefectural Industrial Technology Research Center Research Report, Miyagi Prefectural Government (Industrial Technology Research Center), September 2016, No. 13 (2015), p. 1-7

  The storage circuit 90 disclosed in Non-Patent Document 1 operates theoretically as described above. However, when the circuit is actually configured and experimented, the switch circuit 97 may become conductive before the voltage Vi rises and the voltage Vp exceeds the voltage Vr. In this case, since the capacitor is not sufficiently charged, power supply to the load 98 starts with a voltage insufficient to operate the load 98. That is, the power generated by the power supply 92 continues to be consumed wastefully by the load 98 without charging the capacitor and operating the storage circuit 90 properly.

  Therefore, an object of the present invention is to provide a storage circuit capable of supplying power to a load with a sufficient voltage even when the power supply starts generating power while the capacitor is empty.

  As a result of research, depending on the comparator, while the voltage Vi applied to the comparator rises from zero and reaches a predetermined voltage, the output end is grounded even if the condition that the voltage Vp is lower than the voltage Vr is satisfied. It was found that the potential could not be obtained. In addition, it has been found that, in a storage circuit using such a comparator, the switch circuit may become conductive before the capacitor is sufficiently charged. Therefore, the present invention provides a storage circuit that reliably brings the switch circuit into the cutoff state even when the voltage Vi is close to zero. Specifically, the present invention provides the following storage circuit.

The present invention relates to a first storage circuit,
A storage circuit that stores power supplied from a power source and supplies it to a load,
The storage circuit includes a power supply line connecting the power supply and the load to each other, a capacitor, a voltage detection circuit, a comparison circuit, an additional circuit, and a switch circuit.
The capacitor is connected to the power supply line, stores the power supplied from the power supply, and applies a supply voltage larger than zero to the power supply line.
The voltage detection circuit has a detection input terminal connected to the power supply line, a reference output terminal for outputting a reference voltage, and a detection output terminal for outputting a detection voltage.
The reference voltage is the supply voltage when the supply voltage is lower than a predetermined voltage, and is the predetermined voltage when the supply voltage is equal to or higher than the predetermined voltage.
The detection voltage varies according to the supply voltage and is lower than the supply voltage,
The comparison circuit is connected to the power supply line, and outputs a positive input terminal connected to the reference output terminal, a negative input terminal connected to the detection output terminal, and an additional control voltage. Have an end with
The additional control voltage is a high voltage according to the supply voltage if the voltage applied to the positive input is higher than the voltage applied to the negative input and is applied to the positive input If the voltage is lower than the voltage applied to the negative input, it is a low voltage according to the ground voltage,
The additional circuit has a power supply end connected to the power supply line and a ground end grounded, and a non-ground state for interrupting between the power supply end and the ground end, and the power supply end Transitioning between the ground terminal and the ground state,
The switch circuit is connected between the capacitor and the load in the power supply line, and transitions between a blocking state in which the load is disconnected from the capacitor, and a conductive state in which the load is conducted to the capacitor. Is possible,
The additional circuit comprises an additional control end connected to the output of the comparison circuit and an additional output for outputting a control voltage.
The control voltage is a high voltage according to the supply voltage when the additional circuit is in the non-ground state, and a low voltage according to the ground voltage when the additional circuit is in the ground state Yes,
The additional circuit is in the non-ground state until the supply voltage rises from zero and an additional applied voltage applied to the additional control terminal in response to the additional control voltage reaches an additional threshold. , And after the additional applied voltage reaches the additional threshold, if the additional applied voltage is higher than the additional threshold, the ground state is taken and the additional applied voltage is the additional threshold. If not lower, take the non-ground state,
The switch circuit has a control end connected to the additional output end,
The switch circuit takes the shut-off state until the supply voltage rises from zero and the applied voltage applied to the control terminal reaches a predetermined threshold according to the control voltage, and the applied voltage is the predetermined After reaching the threshold value, the conductive state is taken if the applied voltage is higher than the predetermined threshold, and the shut off state is taken if the applied voltage is lower than the predetermined threshold,
The applied voltage provides a storage circuit lower than the predetermined threshold until the supply voltage rises from zero and the additional applied voltage reaches the additional threshold.

The present invention also relates to a first storage circuit as the second storage circuit, wherein
The power supply end of the additional circuit is connected to the power supply line and to the detection output end of the voltage detection circuit,
The control voltage provides a storage circuit which is a high voltage according to the detection voltage when the additional circuit is in the non-ground state.

The present invention also relates to a second storage circuit as the third storage circuit, wherein
The additional circuit comprises an additional switching element consisting of an N-type MOSFET (metal-oxide-semiconductor field-effect transistor),
In the additional switching element, a gate functions as the additional control end, a source functions as the ground end, a drain functions as the power supply end, and the detection output end of the voltage detection circuit And between the control end of the switch circuit and
The additional threshold is a threshold of a potential difference between the gate and the source for causing conduction between the source and the drain in the additional switching element.
The switch circuit includes a main switching element formed of a P-type MOSFET and a sub switching element formed of an N-type MOSFET.
In the main switching element, a source is connected to the power supply side of the power supply line, and a drain is connected to the load side of the power supply line.
In the sub switching device, a gate functions as the control end, a source is grounded, and a drain is connected to the source of the main switching device via two resistors.
The gate of the main switching element is connected between the two resistors,
The storage circuit is provided, wherein the predetermined threshold is a threshold of a potential difference between the gate and the source for electrically connecting the source and the drain in the sub switching element.

The present invention is any one of the first to third storage circuits as the fourth storage circuit,
The storage circuit is provided wherein the predetermined threshold is equal to or greater than the additional threshold.

  According to the present invention, if the power supply starts to generate power with the capacitor empty, the supply voltage rises from zero and the additional applied voltage applied to the additional control terminal is added after a predetermined time has elapsed Threshold is reached. According to the present invention, the applied voltage applied to the control end is lower than the predetermined threshold until the predetermined time elapses. Thus, the switch circuit can be maintained in the disconnected state until the additional applied voltage exceeds the additional threshold and the additional circuit transitions to the initial ground state. That is, according to the present invention, power can be supplied to the load at a sufficient voltage even when the power supply starts generating power while the capacitor is empty.

FIG. 1 is a block diagram showing a storage circuit according to an embodiment of the present invention. It is a circuit diagram which shows the electrical storage circuit of FIG. FIG. 7 is a view schematically showing an example of operations of the additional circuit and the switch circuit immediately after the switch circuit is switched to the conductive state from the empty state of the capacitor in the storage circuit of FIG. 1. FIG. 7 is a view schematically showing another example of the operation of the additional circuit and the switch circuit from the empty state of the capacitor to immediately after the switch circuit transitions to the conductive state in the storage circuit of FIG. 1. FIG. 3 is a circuit diagram showing a storage circuit (a storage circuit not according to the present invention) in which an additional circuit is removed from the storage circuit of FIG. 2. FIG. 6 schematically shows an example of the operation of the switch circuit of the storage circuit of FIG. 5; It is a circuit diagram which shows the modification of the electrical storage circuit of FIG. FIG. 18 is a circuit diagram showing a modification of the voltage detection circuit of the storage circuit of FIGS. 2 and 7; It is a graph which shows operation | movement of Example 1 of the electrical storage circuit of FIG. It is a graph which shows operation | movement of Example 2 of the electrical storage circuit of FIG. FIG. 2 is a circuit diagram showing a storage circuit of Non-Patent Document 1.

  Referring to FIG. 1, a storage circuit 10 according to the embodiment of the present invention is a circuit of a storage device (not shown), stores power supplied from a power supply 82 and supplies the stored power to a load 88. The storage circuit 10 includes a power supply line 12 connecting a power supply 82 and a load 88 to each other, a capacitor 20, a voltage detection circuit 30, a comparison circuit 40, an additional circuit 50, and a switch circuit 60.

  The power supply 82 in the present embodiment generates a minute power of about 10 μW to 1 mW by harvesting a minute energy from the surrounding environment (that is, by energy harvesting), and generates a minute voltage. The power source 82 is, for example, a photovoltaic cell, a thermoelectric element, or a vibration power generator after rectification.

  The load 88 in the present embodiment is, for example, a step-up DC-DC converter, a step-down DC-DC converter, a step-up / step-down DC-DC converter (hereinafter collectively referred to as "DC-DC converter"), a sensor, and a microcomputer. And electronic devices including a semiconductor element such as a wireless device, and electronic devices which require a predetermined voltage or more at the start of operation of a small motor or the like.

  In use, the load 88 in the present embodiment repeatedly transitions between the operating state and the standby state. Power consumption in the standby state of the load 88 is significantly lower than power consumption in the operating state. On the other hand, the power consumption (operating power) in the operating state of the load 88 is about several mW to several W, which is larger than the power that the power supply 82 can directly supply. Therefore, when the load 88 is directly connected to the power supply 82, the power supply 82 causes a voltage drop, and the voltage of the power supply 82 does not reach the voltage (operation start voltage) for operating the load 88 properly. A DC-DC converter, which is a load 88, is connected between such an electronic device and the storage circuit 10, converts the voltage applied from the storage circuit 10, and supplies the converted voltage to the electronic device. Immediately after the DC-DC converter is powered on, it is necessary to supply power to the DC-DC converter with a voltage higher than the operation start voltage (for example, about 0.6 V to several V) of the DC-DC converter .

  As described below, the storage circuit 10 according to the present embodiment stores minute electric power (electrostatic energy) generated by the power supply 82 in the capacitor 20, and is necessary at a stage where the capacitor 20 is sufficiently charged. The high voltage powers the load 88. However, the present invention is not limited to this. For example, the storage circuit 10 may be connected to a power supply 82 that generates high power and voltage that can be supplied directly to the load 88.

  Hereinafter, first, the structure and function of each circuit of power storage circuit 10 in the present embodiment will be described.

  Referring to FIG. 1, the power supply line 12 is a first connection point (connection point) 122, a second connection point (connection point) 124, and a third connection point (connection point) between the power supply 82 and the switch circuit 60. 126 and a fourth connection point (connection point) 128. The four connection points 122, 124, 126, 128 are arranged in this order from the connection point 122 closest to the power supply 82 to the connection point 128 closest to the switch circuit 60.

  Capacitor 20 is connected to power supply line 12 at connection point 122. Specifically, one end of the capacitor 20 is connected to the connection point 122, and the other end of the capacitor 20 is grounded. The capacitor 20 connected in this manner stores a small amount of power supplied from the power supply 82 and applies a supply voltage Vi larger than zero to the power supply line 12. Supply voltage Vi rises above the activation voltage of load 88 as power is stored in capacitor 20. As described above, when the power generated by the power supply 82 is lower than the operating power of the load 88, when the load 88 is directly connected to the power supply 82, the power supply 82 causes a voltage drop and the voltage generated by the power supply 82 becomes the voltage of the load 88. It becomes lower than the operation start voltage. On the other hand, since the storage circuit 10 includes the capacitor 20 connected to the connection point 122 between the power supply 82 and the load 88, the load 88 is disconnected from the power supply 82 for a certain period of time to store electrostatic energy in the capacitor 20. By doing this, the power can be supplied to the load 88 by the output voltage Vo higher than the operation start voltage of the load 88.

  Specifically, storage circuit 10 takes an initial state and disconnects load 88 from power supply 82 and capacitor 20 until supply voltage Vi rises from zero and reaches start voltage VH sufficiently higher than the operation start voltage of load 88. Do. When the storage circuit 10 is in the initial state, the power generated by the power supply 82 continues to be stored in the capacitor 20 without being supplied to the load 88, whereby the supply voltage Vi gradually increases.

  The storage circuit 10 connects the load 88 to the power supply 82 and the capacitor 20 when the supply voltage Vi rises to the start voltage VH. As a result, the power stored in the capacitor 20 is supplied to the load 88, whereby the supply voltage Vi gradually decreases. The storage circuit 10 disconnects the load 88 from the power supply 82 and the capacitor 20 when the supply voltage Vi falls to the stop voltage VL which is about the lowest voltage at which the load 88 can operate. As a result, the power supplied from the power supply 82 continues to be stored in the capacitor 20 until the supply voltage Vi reaches the start voltage VH again. That is, after the supply voltage Vi first reaches the start voltage VH, the storage circuit 10 enters a steady state, and repeats a cycle consisting of a power supply execution period to the load 88 and a power supply interruption period.

  Capacitor 20 in the present embodiment is configured of one capacitor. However, the present invention is not limited to this. For example, the capacitor 20 may be composed of two or more capacitors, or may include electronic components other than capacitors. When the capacitor 20 includes two or more capacitors, the connection method between the capacitors is not particularly limited. In addition, the capacitor 20 can be composed of various capacitors such as an electrolytic capacitor, a ceramic capacitor, and an electric double layer capacitor.

  The voltage detection circuit 30 is connected to the power supply line 12 at the connection point 124. Specifically, the voltage detection circuit 30 has a detection input 32, a reference output 36, and a detection output 38. The sense input 32 is connected to the power supply line 12 at the connection point 124, whereby the supply voltage Vi is applied to the sense input 32. The reference output 36 outputs a reference voltage Vr in accordance with the applied supply voltage Vi. The detection output terminal 38 outputs a detection voltage Vd according to the applied supply voltage Vi.

  Referring to FIG. 2, more specifically, the voltage detection circuit 30 of the present embodiment includes three resistors R7, R8 and R9, and one constant voltage element (Zener diode) Z1. The resistor R7 and the Zener diode Z1 are connected in series with each other, and the resistor R8 and the resistor R9 are connected in series with each other.

  One end of the resistor R7 is connected to the connection point 124 and functions as a detection input end 32. The other end of the resistor R7 is connected to the cathode of the zener diode Z1, and the cathode of the zener diode Z1 functions as the reference output end 36. The anode of the zener diode Z1 is grounded. By the above-described connection, the reference output terminal 36 outputs the supply voltage Vi when the supply voltage Vi applied to the detection input terminal 32 is lower than the Zener voltage (predetermined voltage) VZ, and the supply voltage Vi is equal to or higher than the predetermined voltage VZ. In the case of, the predetermined voltage VZ is output. In other words, the reference voltage Vr is the supply voltage Vi when the supply voltage Vi is lower than the predetermined voltage VZ, and is the predetermined voltage VZ when the supply voltage Vi is equal to or higher than the predetermined voltage VZ.

  One end of the resistor R 8 is connected to the connection point 124 and functions as the detection input end 32. The other end of the resistor R8 is connected to one end of the resistor R9, and one end of the resistor R9 functions as a detection output end 38. The other end of the resistor R9 is grounded. By the above-mentioned connection, the detection output terminal 38 outputs the detection voltage Vd according to the supply voltage Vi. The detection voltage Vd changes in accordance with the supply voltage Vi and is lower than the supply voltage Vi. In particular, when the storage circuit 10 is in the initial state, the detection voltage Vd of the present embodiment is: detection voltage Vd = supply voltage Vi × R9 × {1 / R8 + 1 / (R4 + R5 + R6)} / [1 + R9 × {1 / R8 + 1 / It is represented by the partial pressure formula of (R4 + R5 + R6)}. In this voltage division equation, RN (N is 8 or 9) indicates the resistance value of the resistor RN. Also in the following description, RN (N is an integer) in the formula indicates the resistance value of the resistor RN.

  Detection voltage Vd of the present embodiment corresponds to a point in time when storage circuit 10 transitions from the initial state to a steady state or a point in time when storage circuit 10 in the steady state transitions between the power supply execution period and the power supply interruption period. Except for the change in proportion to the supply voltage Vi. The constant voltage element Z1 of the present embodiment is a Zener diode, and the predetermined voltage VZ is a Zener voltage. That is, the reference voltage Vr changes in accordance with the magnitude relationship between the supply voltage Vi and the Zener voltage.

  However, the present invention is not limited to this. For example, as long as the detection voltage Vd changes according to the supply voltage Vi, it does not always have to change in proportion to the supply voltage Vi with the same proportionality constant. Therefore, the detection voltage Vd may be obtained by a method other than the division of the supply voltage Vi. The constant voltage element Z1 may not be a zener diode. For example, the constant voltage element Z1 may be a plurality of diodes connected in series in the forward direction. However, in any case, the constant voltage element Z1 needs to be formed of an element having a sufficiently high nominal voltage as the predetermined voltage VZ. More specifically, the predetermined voltage VZ is preferably 1.8 V or more at a nominal value.

  In summary, the voltage detection circuit 30 may be configured in any way as long as the reference voltage Vr defined by the supply voltage Vi and the predetermined voltage VZ and the detection voltage Vd defined by the supply voltage Vi can be obtained. Good. For example, referring to FIG. 8, a voltage detection circuit 30B according to the modification includes four diodes D1, D2, D3 and D4 connected in series instead of the Zener diode Z1. The reference voltage Vr and the detection voltage Vd similar to those of the voltage detection circuit 30 can also be obtained by the voltage detection circuit 30B.

  Referring to FIG. 1, the comparison circuit 40 is connected to the power supply line 12 at the connection point 126, whereby the supply voltage Vi is applied to the comparison circuit 40. The comparison circuit 40 has a positive input end 42, a negative input end 44 and an output end 48. The positive input terminal 42 is connected to the reference output terminal 36 of the voltage detection circuit 30B, and a non-inverted voltage Vp corresponding to the reference voltage Vr is applied. The negative input terminal 44 is connected to the detection output terminal 38 of the voltage detection circuit 30B, and a reverse voltage Vn corresponding to the detection voltage Vd is applied.

  As understood from FIG. 2, in the present embodiment, the non-inversion voltage Vp is equal to the reference voltage Vr. Further, the inversion voltage Vn is equal to the detection voltage Vd or is proportional to the detection voltage Vd in accordance with the state of the storage circuit 10. However, the present invention is not limited to this. For example, the non-inverted voltage Vp may be c × reference voltage Vr (c is a positive constant other than 1).

  Referring to FIG. 1, the comparison circuit 40 compares the non-inversion voltage Vp with the inversion voltage Vn, and outputs an additional control voltage Vca based on the comparison result from the output terminal 48. The additional control voltage Vca is a high voltage according to the supply voltage Vi if the non-inverted voltage Vp is higher than the inverted voltage Vn, and is low according to the ground voltage if the non-inverted voltage Vp is lower than the inverted voltage Vn. It is a voltage.

  More specifically, referring to FIG. 2, the comparison circuit 40 according to the present embodiment includes a comparator 410 and a hysteresis circuit 420. The hysteresis circuit 420 includes two resistors R5 and R6. The resistors R5 and R6 are connected in series with each other.

  The comparator 410 includes three switching elements (a first switching element 402, a second switching element 404, and a third switching element 406), and three resistors R1, R2, and R3. Each of the first switching element 402 and the second switching element 404 is formed of a P-type MOSFET (metal-oxide-semiconductor field-effect transistor), and the third switching element 406 is formed of an N-type MOSFET. Each of the switching elements is capable of transitioning between an ON state in which the source and the drain are conductive and an OFF state in which the source and the drain are cut off, in accordance with a voltage applied to the gate.

  The first switching element 402, the second switching element 404, the resistor R1 and the resistor R2 constitute an input stage of the comparator 410. The gate of the first switching element 402 is connected to the detection output end 38 of the voltage detection circuit 30 via the resistor R 6 of the hysteresis circuit 420 and functions as a negative input end 44. The source of the first switching element 402 is connected to the connection point 126 via the resistor R1, and the supply voltage Vi is applied via the resistor R1. The drain of the first switching element 402 is grounded. The gate of the second switching element 404 is connected to the reference output end 36 of the voltage detection circuit 30 and functions as the positive input end 42. The source of the second switching element 404 is connected to the connection point 126 via the resistor R1, and the supply voltage Vi is applied via the resistor R1. The drain of the second switching element 404 is grounded via the resistor R2.

  The third switching element 406 and the resistor R3 constitute an output stage of the comparator 410. In the third switching element 406, the gate is connected between the drain of the second switching element 404 and the resistor R2, and the source is grounded. The drain of the third switching element 406 is connected to the connection point 126 via the resistor R3, and the supply voltage Vi is applied via the resistor R1. The drain of the third switching element 406 connected in this manner functions as the output end 48.

  The output terminal 48 of the comparison circuit 40 outputs a high voltage corresponding to the supply voltage Vi as an additional control voltage Vca when the storage circuit 10 is in the initial state (that is, until the start voltage VH is reached first). After the supply voltage Vi reaches the start voltage VH, the comparison circuit 40 (output end 48) outputs a low voltage corresponding to the ground voltage as the additional control voltage Vca until the stop voltage VL is reached while falling. In addition, after the supply voltage Vi reaches the stop voltage VL, the comparison circuit 40 (output end 48) increases the high voltage according to the supply voltage Vi until the start voltage VH is reached again while increasing. Output as That is, the comparison circuit 40 functions as a hysteresis comparator having two threshold values (start voltage VH and stop voltage VL).

  Specifically, when the storage circuit 10 is in the steady state, if the inversion voltage Vn is lower than the non-inversion voltage Vp, the first switching element 402 is turned on, and the second switching element 404 is turned off. As a result, the ground voltage is applied to the gate of the third switching element 406, and the third switching element 406 is turned off. That is, the drain (output end 48) of the third switching element 406 is disconnected from the ground, and the output end 48 outputs a high voltage (supply voltage Vi).

  On the other hand, when the storage voltage 10 is in the steady state and the inversion voltage Vn exceeds the non-inversion voltage Vp, the first switching element 402 is turned off, and the second switching element 404 is turned on. As a result, a voltage obtained by dividing the supply voltage Vi by the resistors R2 and R1 is applied to the gate of the third switching element 406, and the third switching element 406 is turned on. That is, the drain (output end 48) of the third switching element 406 conducts to the ground, and the output end 48 outputs a low voltage (ground voltage).

  As understood from the circuit structure of FIG. 2, the circuit obtained by removing the resistor R3 from the comparison circuit 40 functions as an open drain hysteresis comparator. In other words, the comparison circuit 40 can be considered to be a circuit in which the output end 48 of the open drain hysteresis comparator is connected to the power supply line 12 via the resistor R3. From this point of view, the output terminal 48 of the open drain hysteresis comparator is in a high impedance state when the inversion voltage Vn is lower than the non-inversion voltage Vp and is low when the inversion voltage Vn is higher than the non-inversion voltage Vp. Output voltage (ground voltage).

  Referring to FIG. 1, the additional circuit 50 has a power supply end 52, a ground end 54, an additional control end 56, and an additional output end 58. The power supply end 52 is connected to the power supply line 12 at the connection point 128, whereby the supply voltage Vi is applied to the power supply end 52. The ground end 54 is grounded. The additional control end 56 is connected to the output 48 of the comparison circuit 40, and an additional applied voltage Vxa is applied according to the additional control voltage Vca. The additional output end 58 is connected between the power supply end 52 and the connection point 128. The additional circuit 50 operates with the additional applied voltage Vxa and outputs the control voltage Vc from the additional output 58.

  As understood from FIG. 2, in the present embodiment, the additional applied voltage Vxa is equal to the additional control voltage Vca. However, the present invention is not limited to this. For example, the additional applied voltage Vxa may be different from the additional control voltage Vca as long as it changes according to the additional control voltage Vca. For example, the additional applied voltage Vxa may be c × additional control voltage Vca (c is a positive constant other than 1).

  Referring to FIG. 2, more specifically, the additional circuit 50 of the present embodiment includes an additional switching element 50S and a resistor R4. The additional switching element 50S is an N-type MOSFET, and has an ON state in which conduction between the source and the drain is made and an OFF state in which the conduction between the source and the drain is cut off according to a voltage applied to the gate. It is possible to transition between them. The gate of the additional switching element 50S is connected to the output end 48 of the comparison circuit 40 and functions as an additional control end 56. The source of the additional switching element 50S is grounded and functions as a ground end 54. The drain of the additional switching element 50S is connected to the connection point 128 via the resistor R4 and functions as a power supply end 52.

  Referring to FIGS. 1 and 2, in the present embodiment, the power supply end 52 of the additional circuit 50 is connected to the power supply line 12 and to the detection output end 38 of the voltage detection circuit 30. Specifically, referring to FIG. 2, the drain of the additional switching element 50S is connected to the connection point 128, and via the resistor R5 and the resistor R6 of the hysteresis circuit 420, the detection output end 38 of the voltage detection circuit 30. It is connected to the. With this configuration, the detection voltage Vd is applied to the power supply terminal 52. However, the present invention is not limited to this, and the power supply end 52 may be connected to the detection output end 38 as needed.

  The additional circuit 50 has a non-ground state that cuts off between the power supply end 52 and the ground end 54 by the additional applied voltage Vxa applied to the additional control end 56 according to the additional control voltage Vca. It is possible to make a transition between the ground state where the ground 52 is brought into conduction with the ground end 54. When the additional circuit 50 is in the non-ground state, the additional output 58 outputs a high voltage according to the supply voltage Vi. On the other hand, when the additional circuit 50 is in the ground state, the additional output end 58 is grounded and outputs a ground voltage (low voltage). That is, the control voltage Vc is a high voltage according to the supply voltage Vi when the additional circuit 50 is in the non-ground state, and is a low voltage according to the ground voltage when the additional circuit 50 is in the ground state .

  In particular, according to the present embodiment, when the additional circuit 50 is in the non-ground state, the additional output terminal 58 is a high voltage (lower than the supply voltage Vi and higher than the detection voltage Vd) according to the detection voltage Vd. Output high voltage). That is, the control voltage Vc in the present embodiment is a high voltage according to the detection voltage Vd when the additional circuit 50 is in the non-ground state, and according to the ground voltage when the additional circuit 50 is in the ground state. Low voltage.

  The additional circuit 50 configured as described above takes a non-ground state until the supply voltage Vi rises from zero and the additional applied voltage Vxa reaches a predetermined voltage value (additional threshold TA). In the present embodiment, the additional threshold value TA is a threshold value of the potential difference between the gate and the source for conducting between the source and the drain in the additional switching element 50S made of MOSFET (hereinafter simply referred to as "gate threshold"). Say). The predetermined voltage VZ of the constant voltage element Z1 in the present embodiment is high. More specifically, the predetermined voltage VZ is sufficiently higher than the additional threshold value TA. In other words, the additional threshold value TA is lower than the predetermined voltage VZ.

  The additional circuit 50 has a magnitude relationship between the additional applied voltage Vxa and the additional threshold TA after the supply voltage Vi rises from zero and the additional applied voltage Vxa first reaches the additional threshold TA. Transition the state accordingly. More specifically, the additional circuit 50 takes a ground state if the additional applied voltage Vxa is higher than the additional threshold TA and a non-ground state if the additional applied voltage Vxa is lower than the additional threshold TA. I take the.

  Referring to FIG. 1, switch circuit 60 is connected between power supply line 12 and capacitor 20 and load 88. The switch circuit 60 has a control end 66. The control end 66 is connected to the additional output end 58 of the additional circuit 50, to which an applied voltage Vx according to the control voltage Vc is applied. As understood from FIG. 2, in the present embodiment, the applied voltage Vx is equal to the control voltage Vc. However, the present invention is not limited to this, and the applied voltage Vx may be different from the control voltage Vc as long as it changes according to the control voltage Vc. For example, the applied voltage Vx may be c × control voltage Vc (c is a positive constant other than 1).

  Referring to FIG. 1, switch circuit 60 cuts off load 88 from capacitor 20 by an applied voltage Vx applied to control end 66 in accordance with control voltage Vc, and conducts that brings load 88 into conduction with capacitor 20. It is possible to transition between states. When the switch circuit 60 is in the cut-off state, the power generated by the power supply 82 continues to be stored in the capacitor 20 without being supplied to the load 88, whereby the supply voltage Vi becomes gradually higher. On the other hand, when the switch circuit 60 is in the conductive state, the power generated by the power supply 82 is supplied to the load 88 together with the power stored in the capacitor 20, whereby the supply voltage Vi gradually decreases.

  Referring to FIG. 2, more specifically, switch circuit 60 of the present embodiment includes two switching elements (main switching element 60M and sub switching element 60S) and three resistors R11, R12, and R13. ing. The main switching element 60M is formed of a P-type MOSFET, and the sub switching element 60S is formed of an N-type MOSFET. Each of the switching elements is capable of transitioning between an ON state in which the source and the drain are conductive and an OFF state in which the source and the drain are cut off, in accordance with a voltage applied to the gate.

  In the main switching element 60M, the source is connected to the power supply 82 side of the power supply line 12, and the drain is connected to the load 88 side of the power supply line 12. The gate of the auxiliary switching element 60S is connected to the additional output end 58 of the additional circuit 50 via a resistor R11 and functions as a control end 66. In particular, in the present embodiment, the gate of the sub switching element 60S is connected to the detection output end 38 of the voltage detection circuit 30 via the additional output end 58, the resistor R5 and the resistor R6. That is, the drain of the additional switching element 50S of the additional circuit 50 is connected between the detection output end 38 of the voltage detection circuit 30 and the control end 66 of the switch circuit 60. In the secondary switching element 60S, the source is grounded, and the drain is connected to the source of the main switching element 60M via the two resistors R12 and R13. The gate of the main switching element 60M is connected between the two resistors R12 and R13.

  The switch circuit 60 configured as described above is in the cutoff state until the supply voltage Vi rises from zero and the applied voltage Vx reaches a predetermined voltage value (predetermined threshold value TP). In the present embodiment, the predetermined threshold value TP is a threshold value (gate threshold value) of the potential difference between the gate and the source for causing conduction between the source and the drain in the sub switching element 60S made of a MOSFET. The predetermined voltage VZ of the constant voltage element Z1 in the present embodiment is sufficiently higher than the predetermined threshold TP. In other words, the predetermined threshold value TP is lower than the predetermined voltage VZ.

  After the supply voltage Vi rises from zero and the applied voltage Vx first reaches the predetermined threshold TP, the switch circuit 60 causes a state transition in accordance with the magnitude relationship between the applied voltage Vx and the predetermined threshold TP. More specifically, the switch circuit 60 is in a conductive state when the applied voltage Vx is higher than the predetermined threshold TP, and is in a disconnected state when the applied voltage Vx is lower than the predetermined threshold TP.

  Hereinafter, the operation of power storage circuit 10 configured as described above will be described in detail. The operation of the storage circuit 10 is influenced by the gate thresholds of the first switching element 402, the second switching element 404 and the third switching element 406 of the comparison circuit 40 in addition to the predetermined threshold value TP and the additional threshold value TA. However, first, the operation of the storage circuit 10 will be described without directly touching the gate threshold of the comparison circuit 40, and then the gate threshold of the comparison circuit 40 will be described.

  Referring to FIGS. 2 and 3, capacitor 20 is empty at the time when power storage circuit 10 starts operating (zero time when the value of the time axis in FIG. 3 is 0). Therefore, each of the supply voltage Vi, the additional control voltage Vca (= additional applied voltage Vxa) and the control voltage Vc (= applied voltage Vx) is 0V. At this time, each of the switching elements (the first switching element 402, the second switching element 404, the third switching element 406, the additional switching element 50S, the main switching element 60M and the auxiliary switching element 60S) is in the OFF state. Because the additional switching element 50S is in the OFF state, the additional circuit 50 is in the non-ground state. Since the main switching element 60M is in the OFF state, the switch circuit 60 is in the disconnection state. In addition, the storage circuit 10 is in an initial state.

  When the storage circuit 10 starts operating, the capacitor 20 is gradually charged, whereby the supply voltage Vi gradually increases. Each of the additional switching element 50S and the sub switching element 60S maintains the OFF state until the storage circuit 10 starts operation and a predetermined time T0 is reached. During this time, the supply voltage Vi is applied to the additional control end 56 of the additional circuit 50 (ie, the gate of the additional switching element 50S) as the additional applied voltage Vxa (= additional control voltage Vca). Further, an applied voltage Vx (= control voltage Vc) corresponding to the detection voltage Vd is applied to the control end 66 of the switch circuit 60 (that is, the gate of the sub switching element 60S). Specifically, the applied voltage Vx is higher than the detection voltage Vd and lower than the supply voltage Vi.

  As described above, the detection voltage Vd is lower than the supply voltage Vi. That is, the control voltage Vc is lower than the additional control voltage Vca. Thus, for example, by using MOSFETs having the same gate threshold as the additional switching element 50S and the sub switching element 60S, the additional control voltage Vca is obtained at time T0 before the control voltage Vc reaches the predetermined threshold TP. Reaches the additional threshold TA.

  Since the control voltage Vc is lower than the gate threshold of the sub switching element 60S until the additional control voltage Vca reaches the additional threshold TA at time T0, the sub switching element 60S maintains the OFF state. Therefore, the supply voltage Vi is applied to the gate and the source of the main switching element 60M, and the main switching element 60M maintains the OFF state. That is, the switch circuit 60 maintains the cutoff state, and the capacitor 20 continues to be charged.

  After the additional control voltage Vca reaches the additional threshold TA at time T0, the supply voltage Vi continues to rise. As a result, the additional control voltage Vca continues to rise above the gate threshold of the additional switching element 50S, and the additional switching element 50S is turned on immediately after time T0. That is, the additional circuit 50 is in the ground state. When the additional circuit 50 is in the ground state, the control voltage Vc becomes the ground voltage (0 V), and the auxiliary switching element 60S maintains the OFF state. Therefore, the supply voltage Vi continues to be applied to the gate and the source of the main switching element 60M, and the main switching element 60M maintains the OFF state. That is, the switch circuit 60 maintains the cutoff state, and the capacitor 20 continues to be charged.

  Between zero time and T0 time, a current path is formed from the connection point 128 having the supply voltage Vi to the detection output end 38 having the detection voltage Vd via the resistors R4, R5 and R6. Therefore, the inversion voltage Vn is higher than the detection voltage Vd and lower than the supply voltage Vi. During this time, since the non-inversion voltage Vp is equal to the supply voltage Vi, the inversion voltage Vn is lower than the non-inversion voltage Vp. On the other hand, immediately after time T0, a current path is formed from the detection output terminal 38 to the ground via the resistor R6, the resistor R5, and the drain and source of the additional switching element 50S. Therefore, after time T0, the inversion voltage Vn becomes a voltage obtained by dividing the detection voltage Vd by the resistors R5 and R6, and becomes lower than the detection voltage Vd. Specifically, the inversion voltage Vn after time T0 is expressed by a divided voltage expression of detection voltage Vd × R5 / (R5 + R6).

  The supply voltage Vi continues to rise after time T0. As described above, the predetermined voltage VZ according to the present embodiment is higher than the additional threshold value TA. Therefore, the supply voltage Vi reaches the predetermined voltage VZ at time T1 after time T0, and at this time, the reference voltage Vr (non-inverted voltage Vp) becomes the predetermined voltage VZ.

  The supply voltage Vi continues to rise after time T1, and the detection voltage Vd and the inversion voltage Vn continue to rise. On the other hand, the non-inverted voltage Vp is maintained at the predetermined voltage VZ. As a result, the inversion voltage Vn becomes equal to the non-inversion voltage Vp at a predetermined time T2, and then exceeds the non-inversion voltage Vp. At time T2, the supply voltage Vi reaches the start voltage VH. As described above, in particular, the rising speed of the inversion voltage Vn relative to the rising of the supply voltage Vi is slow between the time T0 and the time T2. Therefore, a large amount of power is accumulated in capacitor 20 between time T0 and time T2.

  The non-inversion voltage Vp is higher than the inversion voltage Vn from the zero time to the T2 time. At any time during this period, the first switching element 402 of the comparison circuit 40 is turned on. On the other hand, the second switching element 404 of the comparison circuit 40 maintains the OFF state from the zero time to the T2 time. Since the second switching element 404 is in the OFF state, the ground voltage (0 V) is applied to the gate of the third switching element 406 of the comparison circuit 40, and the third switching element 406 maintains the OFF state.

  After time T2, the non-inverted voltage Vp becomes lower than the inverted voltage Vn. As a result, in the comparison circuit 40, the first switching element 402 is turned off, and the second switching element 404 is turned on. When the second switching element 404 is turned on, a voltage obtained by dividing the supply voltage Vi by the resistors R2 and R1 is applied to the gate of the third switching element 406, and the third switching element 406 is turned on. .

  When the third switching element 406 is turned on, the additional control voltage Vca becomes the ground voltage (0 V), and the additional switching element 50S is turned off. That is, the additional circuit 50 is in the non-ground state. When the additional circuit 50 is in the non-ground state, the control voltage Vc becomes equal to the detection voltage Vd, and the sub switching element 60S is in the ON state. When the sub switching element 60S is turned on, the ground voltage is applied to the gate and the supply voltage Vi is applied to the source in the main switching element 60M. As a result, the main switching element 60M is turned on, and the switch circuit 60 is turned on. In the conductive state, the power generated by the power supply 82 is supplied to the load 88 together with the power stored in the capacitor 20.

  In the conductive state, the supply voltage Vi gradually decreases. In the conductive state, a current path is again formed from the connection point 128 having the supply voltage Vi to the detection output end 38 having the detection voltage Vd via the resistors R4, R5 and R6. Therefore, the inversion voltage Vn becomes larger than the detection voltage Vd again. Specifically, the inversion voltage Vn in the conductive state is expressed by the following expression: detection voltage Vd + (supply voltage Vi−detection voltage Vd) × R6 / (R4 + R5 + R6). In the conductive state, as the supply voltage Vi decreases, the inversion voltage Vn also decreases. The inversion voltage Vn is higher at the time T2 as described above, and thus is higher than the non-inversion voltage Vp for a while.

  The inversion voltage Vn continues to fall with the drop of the supply voltage Vi and eventually becomes lower than the non-inversion voltage Vp. At this time, the first switching element 402 is turned on, and the second switching element 404 is turned off (not shown in FIG. 3). As a result, the additional circuit 50 is brought to the ground state again, and the switch circuit 60 is brought to the interruption state again. At this time, the supply voltage Vi reaches the stop voltage VL.

  As understood from the above description, after the supply voltage Vi first reaches the start voltage VH, the storage circuit 10 is in the steady state, and comprises the power supply execution period to the load 88 and the power supply interruption period. Repeat the cycle. In the steady state, the supply voltage Vi rises and falls between the start voltage VH and the stop voltage VL.

  In the present embodiment, the influence of the characteristics of the switching elements (the first switching element 402, the second switching element 404, the third switching element 406, and the additional switching element 50S) on the start voltage VH and the stop voltage VL is small. When calculated without considering the influence of the characteristics of the switching element, the start voltage VH is a predetermined voltage VZ × {R8 + (R8 / R9 + 1) × (R5 + R6)} / R5, and the stop voltage VL is a predetermined voltage VZ × { It is (R4 + R5 + R6) * (R8 + R9) + R8 * R9} / {(R4 + R5 + R6) * R9 + (R6 + R9) * R8}. By adjusting the above-described resistance value in storage circuit 10, start voltage VH and stop voltage VL can be set to values necessary for operating load 88. However, the actual stop voltage VL is not lower than the gate threshold of the switching element (in particular, the additional threshold TA).

  In the above description, although the gate threshold of each of the switching elements (the first switching element 402, the second switching element 404, and the third switching element 406) is not directly touched, each of the switching elements has a predetermined threshold value TP. And the additional threshold value TA, it has a gate threshold value sufficiently lower than the predetermined voltage VZ. More specifically, each gate threshold of the switching element is lower than the start voltage VH and the stop voltage VL. As described below, according to the present embodiment, since the drain of the third switching element 406 is connected to the power supply line 12, even though the switching element has the gate threshold as described above, the storage of electricity is also possible. Circuit 10 operates properly.

  When the power supply 82 starts generating power while the capacitor 20 is empty, a voltage higher than the detection voltage Vd and lower than the supply voltage Vi is applied to the gate of the first switching element 402, and the second switching element A reference voltage Vr (= supply voltage Vi) higher than the gate voltage of the first switching element 402 is applied to the gate 404. Therefore, by appropriately setting the proportional constant of the detection voltage Vd with respect to the supply voltage Vi, the first switching is performed before the second switching element 404 is turned ON and before the supply voltage Vi reaches the predetermined voltage VZ. The voltage difference between the source and the gate of the element 402 reaches the gate threshold, and the first switching element 402 is turned on. As a result, in the third switching element 406, the voltage of the gate becomes the same ground voltage as the voltage of the source until the second switching element 404 is in the ON state, and the third switching element 406 maintains the OFF state.

  According to the present embodiment, the gate threshold of the third switching element 406 is lower than the start voltage VH. For this reason, the third switching element 406 maintains the OFF state until the second switching element 404 is turned ON, and turns ON when the second switching element 404 is turned ON. The drain of the third switching element 406 is connected to the power supply line 12 via the resistor R3. Therefore, the additional control voltage Vca is maintained at the supply voltage Vi until the third switching element 406 is first turned on (that is, until the supply voltage Vi first reaches the start voltage VH), and the additional switching element After the 50S first turns on, it remains on.

  The storage circuit 10 according to the present embodiment operates as described above. In addition, according to power storage circuit 10 according to the present embodiment, control voltage Vc already exceeds predetermined threshold value TP of switch circuit 60 immediately after inversion voltage Vn first becomes equal to non-inversion voltage Vp. However, the present invention is not limited to this.

  Referring to FIGS. 2 and 4, the control voltage Vc may exceed the predetermined threshold TP of the switch circuit 60 after the inversion voltage Vn first becomes equal to the non-inversion voltage Vp. In this case, the value of the supply voltage Vi when the control voltage Vc initially rises to the predetermined threshold value TP becomes the start voltage VH. According to the modification (see FIG. 4), similarly to the present embodiment (see FIG. 3), after switch circuit 60 is brought into the first conduction state, storage circuit 10 is brought into the steady state, and load 88 The cycle including the power supply execution period and the power supply interruption period is repeated. In the steady state, the supply voltage Vi rises and falls between the start voltage VH and the stop voltage VL.

  Referring to FIG. 1, storage circuit 10 according to the present embodiment includes an additional circuit 50 connected between comparison circuit 40 and switch circuit 60. The applied voltage Vx having a voltage value lower than the additional applied voltage Vxa can be reliably applied.

  5 and 6, the storage circuit 10X is a conventional storage circuit (see FIG. 11) and does not include the additional circuit 50 (see FIG. 2). The storage circuit 10X further includes a comparison circuit 40X slightly different from the comparison circuit 40 (see FIG. 2) of the storage circuit 10. If the supply voltage Vi rises until the inversion voltage Vn exceeds the non-inversion voltage Vp (see the broken line in FIG. 6), the storage circuit 10X is similar to the storage circuit 10 (see FIGS. 1 to 3). Operate. However, the control voltage Vc (= additional control voltage Vca) of the storage circuit 10X is earlier than the inversion voltage Vn reaches the non-inversion voltage Vp due to various factors such as resistance values of the resistors R1 to R6, R8 and R9. In some cases, the predetermined threshold TP may be reached. In this case, since the capacitor 20 is not sufficiently charged, the power supply to the load 88 starts with the output voltage Vo which is insufficient for operating the load 88. That is, the power generated by the power supply 82 continues to be consumed wastefully by the load 88 without charging the capacitor 20 and operating the storage circuit 10X properly.

  Referring to FIGS. 1 to 3, according to the present embodiment, when the power supply 82 starts generating power while the capacitor 20 is empty, the supply voltage Vi rises from zero and the comparison circuit 40 The additional applied voltage Vxa applied to the additional control end 56 reaches the additional threshold TA after a predetermined time has elapsed. On the other hand, since the applied voltage Vx applied to the control end 66 is applied not by the comparison circuit 40 but by the additional circuit 50, the voltage value lower than the predetermined threshold can be maintained until the predetermined time elapses. Therefore, the switch circuit 60 can be maintained in the cutoff state until the additional applied voltage Vxa exceeds the additional threshold TA and the additional circuit 50 transitions to the initial ground state. According to the present embodiment, setting start voltage VH and stop voltage VL in accordance with the operating voltage of load 88 is sufficient even when power supply 82 starts generating power when capacitor 20 is empty. Power can be supplied to the load 88 at the output voltage Vo.

  Referring to FIG. 2, according to the present embodiment, the control voltage Vc changes in accordance with the detection voltage Vd lower than the supply voltage Vi. That is, according to the present embodiment, the control voltage Vc can be set to a voltage value lower than the additional control voltage Vca, whereby the applied voltage Vx is set to a voltage value lower than the predetermined threshold value TP until the predetermined time elapses. It can be maintained.

  According to the present embodiment, the comparison circuit 40, the additional circuit 50, and the switch circuit 60 can be formed by a combination of single function elements without using a semiconductor manufacturing process. Therefore, the storage circuit 10 can be constructed inexpensively and easily without using an IC (integrated circuit). Furthermore, the storage circuit 10 can be operated with any voltage and current without being restricted by the operating conditions of the IC.

  Referring to FIGS. 2 and 3, each circuit of power storage circuit 10 according to the present embodiment has the above-described structure and function. However, the present invention is not limited to this, and each circuit of the storage circuit 10 can be variously modified. Hereinafter, preferable structures and modified examples of each circuit of the storage circuit 10 will be described.

  Referring to FIGS. 3 to 5, the illustrated resistance RN (N is an integer) is not limited to one resistor, and may be a combination of a plurality of resistors.

  According to the present embodiment, by adjusting the resistance value of the resistor R8 of the voltage detection circuit 30 and the resistance value of the resistor R9, the detection voltage Vd can be made sufficiently lower than the supply voltage Vi. Therefore, the predetermined threshold value TP may be equal to or less than the additional threshold value TA. However, in order to make the applied voltage Vx lower than the predetermined threshold value TP more reliably until time T2 in FIG. 3, the predetermined threshold value TP is preferably equal to or higher than the additional threshold value TA.

  The supply voltage Vi decreases rapidly as power supply to the load 88 starts. Therefore, when the load 88 is an electronic device including semiconductor elements such as a sensor, a microcomputer, a wireless device, and a small motor, it is preferable to connect a DC-DC converter between the storage circuit 10 and the load 88. Further, the power stored in the capacitor 20 is proportional to the square of the supply voltage Vi. For this reason, it is preferable that the start voltage VH be as high as possible within the range of voltages that the load 88 can tolerate. The start voltage VH may be set, for example, in consideration of the power generation capability of the power supply 82 and the time required for the load 88 to start operation.

  When the load 88 repeats the operating state and the standby state, the resistance value or the like in the storage circuit 10 is consumed, and the power stored in the capacitor 20 in the initial state of the storage circuit 10 consumes the load 88 in the conductive state of the storage circuit 10 It is preferable to set so as to be larger than the power. In this case, the supply voltage Vi does not drop to the stop voltage VL, and the load 88 can continue to be supplied with a voltage higher than the stop voltage VL.

  From the viewpoint of reducing the capacity of capacitor 20 and reducing the size of the power storage device (not shown), it is preferable to make the difference between start voltage VH and stop voltage VL as large as possible. Specifically, the power that can be extracted from the capacitor 20 is proportional to the difference between the square of the start voltage VH and the square of the stop voltage VL. Therefore, the stop voltage VL is preferably as close to 0 V as possible.

  In the present embodiment, each of the switching elements is a MOS type field-effect transistor (FET) having excellent power saving performance. However, the present invention is not limited to this, and each of the switching elements may be a field effect transistor (FET) or a bipolar transistor.

  When using a FET including a MOS FET as a switching element, the minimum voltage (gate threshold) between the gate and the source necessary to switch between the ON state and the OFF state is nominally 1.0 V or less Is preferred. When a bipolar transistor is used as the switching element, each of the first switching element 402, the second switching element 404 and the main switching element 60M uses a PNP type, and the third switching element 406, the additional switching element 50S and the auxiliary switching Each of the elements 60S may use an NPN type.

  Regardless of which switching element is used, it is preferable that the first switching element 402 and the second switching element 404 constituting the input stage of the comparator 410 have the same characteristics as each other. More specifically, when using a MOS FET, the gate threshold, the current flowing between the gate and the source, and the current flowing between the source and the drain when in the OFF state are the same. Is preferred. Furthermore, the gate threshold values of the first switching element 402 and the second switching element 404 are as low as possible such that the first switching element 402 and the second switching element 404 can transition to the ON state at the stage where the supply voltage Vi is low. Is preferred. Moreover, it is preferable that the additional switching element 50S and the sub switching element 60S have the same characteristics as each other.

  From the viewpoint of reducing the current consumption of the storage circuit 10 and making the storage circuit 10 compatible with the power supply 82 generating a small current, the combined resistance R of the voltage detection circuit 30, the comparison circuit 40 and the additional circuit 50 (power supply The higher the combined resistance value between 82 and ground, the better. In the present embodiment, the influence of the characteristics of the switching elements (the first switching element 402, the second switching element 404, the third switching element 406, and the additional switching element 50S) on the combined resistance R is small.

  According to the calculation without considering the influence of the characteristics of the switching element, the combined resistance R = 1 / [1 / (R1 + R2) + 1 / R3 + 1 / R7 + until the supply voltage Vi falls from the start voltage VH to the stop voltage VL. (R4 + R5 + R6 + R8) / {(R8 + R9) × (R4 + R5 + R6) + R8 × R9}], and the combined resistance R = 1 / [1 / R1 + until the supply voltage Vi rises from the stop voltage VL to the start voltage VH. It is 1 / R4 + 1 / R7 + (R5 + R6 + R9) / {(R5 + R6 + R9) * R8 + (R5 + R6) * R9}]. By adjusting the above-described resistance value in the storage circuit 10, the combined resistance R can be set to a necessary value.

  In order to operate storage circuit 10 stably, the gate of additional switching element 50S may be connected between resistor R3 and the drain of third switching element 406 via a resistor (not shown). good. Similarly, the gate of the third switching element 406 may be connected between the resistor R2 and the drain of the second switching element 404 via a resistor (not shown).

  As described above, according to the present embodiment, the additional applied voltage Vxa applied to the additional control end 56 changes in accordance with the supply voltage Vi, and the applied voltage Vx applied to the control end 66 is It changes according to the detection voltage Vd lower than the supply voltage Vi. By setting the applied voltage Vx lower than the additional applied voltage Vxa, the timing when the sub switching element 60S first transitions to the ON state (first transition timing) after the additional switching element 50S first transitions to the ON state It can be delayed. However, the method of delaying the above-mentioned first transition timing is not limited to the present embodiment as described below.

  Referring to FIG. 7 in combination with FIG. 2, the storage circuit 10A according to the modification includes the same power supply line 12 as the storage circuit 10, the capacitor 20, the voltage detection circuit 30, the additional circuit 50, and the switch circuit 60. Have. Further, the storage circuit 10A includes a comparison circuit 40A slightly different from the comparison circuit 40 of the storage circuit 10, and includes a delay circuit 430A not included in the storage circuit 10. Each of the power supply line 12, the capacitor 20, the voltage detection circuit 30, the additional circuit 50 and the switch circuit 60 operates in the same manner as the storage circuit 10. The comparison circuit 40A is a circuit obtained by removing the hysteresis circuit 420 from the comparison circuit 40 of the storage circuit 10, and operates in the same manner as the comparator 410 of the storage circuit 10. The structure and function of the delay circuit 430A will be mainly described below.

  Referring to FIG. 7, delay circuit 430A includes a resistor R10 and a capacitor C1. One end of the resistor R10 is connected between the resistor R4 and the drain of the additional switching device 50S, and the other end of the resistor R10 is connected to the gate of the sub switching device 60S via the resistor R11. Unlike the storage circuit 10 (see FIG. 2), the gate of the sub switching element 60S is not connected to the detection output end 38 of the voltage detection circuit 30. One end of the capacitor C1 is connected between the resistor R10 and the resistor R11, and the other end of the capacitor C1 is grounded.

  Referring to FIG. 7 in conjunction with FIG. 3, when the storage circuit 10A starts to operate and the supply voltage Vi rises from zero, the additional control voltage Vca is supplied to the supply voltage Vi in the same manner as the storage circuit 10 (see FIG. 2). , And reaches an additional threshold TA at time T0. Thereafter, the additional control voltage Vca further rises. The control voltage Vc also rises in accordance with the supply voltage Vi from the zero time to the T0 time. However, according to this modification, since the capacitor C1 of the delay circuit 430A is provided between the additional circuit 50 and the switch circuit 60, the applied voltage Vx applied to the gate of the sub switching element 60S is It rises behind the rise of the control voltage Vc. That is, the applied voltage Vx is lower than the control voltage Vc.

  According to this modification, since the applied voltage Vx is lower than the control voltage Vc, the applied voltage Vx is set to the predetermined threshold TP until the supply voltage Vi rises from zero and the additional applied voltage Vxa reaches the additional threshold TA. Lower than. Therefore, the switch circuit 60 can be maintained in the cutoff state until the additional applied voltage Vxa exceeds the additional threshold TA and the additional circuit 50 transitions to the initial ground state. That is, according to the present modification, even when the power supply 82 starts generating power in a state where the capacitor 20 is empty without changing the control voltage Vc according to the detection voltage Vd, a load with a sufficient output voltage Vo Power can be supplied to 88.

  According to this modification, since delay circuit 430A is provided instead of hysteresis circuit 420 (see FIG. 2), storage circuit 10A is in the steady state after switch circuit 60 is brought into the first conduction state. , A cycle consisting of a power supply execution period to the load 88 and a power supply interruption period is repeated. In the steady state of the storage circuit 10A, the supply voltage Vi fluctuates between the start voltage VH and the stop voltage VL.

  Hereinafter, the operation of the storage circuit 10 (see FIG. 2) will be more specifically described using an example.

Example 1
In the simulator, the storage circuit 10 of FIG. 2 was constructed as the circuit of the first embodiment to verify the operation. The capacitance value and resistance value of each element in the circuit of Example 1 are as shown in Table 1.

  Based on the resistance values described in Table 1, the start voltage VH, the stop voltage VL, and the combined resistance R of the circuit of Example 1 were calculated. In this calculation, the influence of the switching elements (the first switching element 402, the second switching element 404, the third switching element 406, the additional switching element 50S, the main switching element 60M, and the auxiliary switching element 60S) was not considered. As a result of the calculation, the start voltage VH was 4.5 V and the stop voltage VL was 1.3 V. The respective gate thresholds VGS (th) of the switching elements were lower than the calculated stop voltage VL. The combined resistance R is 33 kΩ until the supply voltage Vi falls from the start voltage VH to the stop voltage VL, and is 33 kΩ until the supply voltage Vi rises from the stop voltage VL to the start voltage VH. was.

The circuit of Example 1 was connected between the power supply 82 and the load 88 to verify the operation of the circuit of Example 1. In the operation verification, eight photovoltaic cells connected in series were used as the power supply 82, and a 10 Ω resistor was used as the load 88. In each of the photovoltaic cells, the light receiving area was 57.8 cm ² , the open circuit voltage Voc by direct sunlight was 1 V, and the short circuit current Isc by direct sunlight was 500 mA. A light having a spectrum equivalent to that of sunlight was applied at an intensity of 10 mW / cm ² from vertically above the photovoltaic cell, whereby a current of about 50 mA was supplied from the power supply 82 to the circuit of Example 1. The Zener voltage VZ (nominal value: 1.8 V) of the Zener diode Z1 differs depending on the value of the current supplied from the power supply 82, and was 0.9 V under the above-mentioned conditions. Under the above conditions, the supply voltage Vi, the reference voltage Vr (non-inverted voltage Vp), and the detection voltage Vd are determined with the capacitor 20 being empty (ie, the capacitor 20 has a voltage of 0 V) as the start point (0 second). Fluctuations of the reverse voltage Vn, the control voltage Vc, and the output voltage Vo were measured by a simulator.

  The measurement results are shown in FIG. Hereinafter, the operation of the circuit of the first embodiment will be described with reference to FIGS. 2 and 9. In the following description, it is assumed that gate threshold values VGS (th) of the first switching element 402, the second switching element 404, and the third switching element 406 are extremely close to zero.

  At the start point, each of the switching elements is in an initial state (OFF state). For this reason, the switch circuit 60 is in the cutoff state. Charging of the empty capacitor 20 begins at the start point. As the capacitor 20 is charged, the supply voltage Vi gradually rises.

  Between the start point and T0, the detection voltage Vd and the inversion voltage Vn gradually increase with the increase of the supply voltage Vi. During this time, since the supply voltage Vi is lower than the Zener voltage VZ, the Zener diode Z1 is in the OFF state, and as the supply voltage Vi rises, the reference voltage Vr (non-inversion voltage Vp) gradually rises. During this time, the reference voltage Vr is equal to the supply voltage Vi, and the inversion voltage Vn is higher than the supply voltage Vi. That is, since the non-inversion voltage Vp is higher than the inversion voltage Vn, the first switching element 402 is in the ON state, and the second switching element 404 is in the OFF state. As a result, the voltage of the gate of the third switching element 406 becomes the ground voltage (0 V), and the third switching element 406 maintains the OFF state, and additional control equal to the supply voltage Vi to the gate of the additional switching element 50S. A voltage Vca (= additional applied voltage Vxa) is applied.

  From the start point to T0, the additional control voltage Vca is lower than the additional threshold TA of the additional switching element 50S. Therefore, the additional switching element 50S maintains the OFF state, and the control voltage Vc (= applied voltage Vx) equal to the detection voltage Vd is applied to the gate of the sub switching element 60S. At this time, the control voltage Vc is lower than the predetermined threshold value TP of the auxiliary switching element 60S. Therefore, the sub switching element 60S maintains the OFF state, and the supply voltage Vi is applied to the source and the gate of the main switching element 60M. As a result, the main switching element 60M maintains the OFF state, and the switch circuit 60 maintains the OFF state.

  At T0, the additional control voltage Vca reaches an additional threshold TA. For this reason, the additional switching element 50S is turned on, and the control voltage Vc rapidly falls to become the ground voltage at T0 '. At this time, a current path grounded via the resistor R6, the resistor R5, and the additional switching element 50S is formed, and the inversion voltage Vn temporarily drops.

  During the period from T0 'to T1, the inversion voltage Vn rises again according to the detection voltage Vd. However, the supply voltage Vi is still lower than the Zener voltage VZ, and the non-inversion voltage Vp is higher than the inversion voltage Vn. As a result, the first switching element 402 maintains the ON state, and the second switching element 404 and the third switching element 406 maintain the OFF state, and add to the gate of the additional switching element 50S equal to the supply voltage Vi. Control voltage Vca is applied.

  From T0 'to T1, the additional control voltage Vca is equal to or higher than the additional threshold value TA of the additional switching element 50S. Therefore, the additional switching element 50S is turned on, and a ground voltage is applied to the gate of the sub switching element 60S. Therefore, the sub switching element 60S maintains the OFF state, and the supply voltage Vi is applied to the source and the gate of the main switching element 60M. As a result, the main switching element 60M maintains the OFF state, and the switch circuit 60 maintains the OFF state.

  At T1, the supply voltage Vi reaches the Zener voltage VZ. Therefore, the Zener diode Z1 becomes conductive, and the reference voltage Vr becomes the Zener voltage VZ.

  Between T1 and T2, the inversion voltage Vn continues to rise in accordance with the detection voltage Vd. However, the inversion voltage Vn is lower than the non-inversion voltage Vp (the Zener voltage VZ). Therefore, the additional control voltage Vca equal to the supply voltage Vi continues to be applied to the gate of the additional switching element 50S, and the additional switching element 50S maintains the ON state. Therefore, each of the auxiliary switching element 60S and the main switching element 60M maintains the OFF state, and the switch circuit 60 maintains the OFF state.

  At T2, the supply voltage Vi reaches the start voltage VH, and the inversion voltage Vn reaches the non-inversion voltage Vp (zener voltage VZ). Thereafter, since the inversion voltage Vn becomes higher than the non-inversion voltage Vp, the first switching element 402 is turned off, and the second switching element 404 is turned on. Therefore, the voltage of the gate of the third switching element 406 becomes a voltage obtained by dividing the supply voltage Vi by the resistors R1 and R2, and the third switching element 406 is turned on. As a result, the additional control voltage Vca becomes the ground voltage, and the additional switching element 50S is in the OFF state.

  At T2, a current path is formed from the connection point 128 to the detection output end 38 via the resistor R4, the resistor R5 and the resistor R6, and the detection voltage Vd and the inversion voltage Vn rise sharply. Further, with the formation of the current path, the control voltage Vc becomes a voltage corresponding to the supply voltage Vi. Therefore, the sub switching element 60S is turned on, and a ground voltage is applied to the gate of the main switching element 60M. As a result, the main switching element 60M is turned on, and the switch circuit 60 is turned on.

  From T2 to T3, the charge of the capacitor 20 is consumed by the load 88, and the supply voltage Vi gradually falls. As the supply voltage Vi decreases, the detection voltage Vd and the inversion voltage Vn which have rapidly increased at T2 gradually decrease. However, the inversion voltage Vn remains higher than the non-inversion voltage Vp (the Zener voltage VZ), and the third switching element 406 maintains the ON state. Therefore, the additional switching element 50S maintains the OFF state, and the sub switching element 60S maintains the ON state. As a result, the main switching element 60M maintains the ON state, and the switch circuit 60 maintains the conduction state.

  At T3, the supply voltage Vi reaches the stop voltage VL, and the inversion voltage Vn reaches the non-inversion voltage Vp (zener voltage VZ). Thereafter, since the inversion voltage Vn becomes lower than the non-inversion voltage Vp, the first switching element 402 is turned on, and the second switching element 404 is turned off. Therefore, the voltage of the gate of the third switching element 406 is the ground voltage, and the third switching element 406 is in the OFF state. As a result, the additional control voltage Vca becomes the supply voltage Vi, and the additional switching element 50S is in the ON state.

  At T3, the current path leading from the connection point 128 to the detection output end 38 via the resistor R4, the resistor R5 and the resistor R6 disappears, and the detection voltage Vd and the inversion voltage Vn fall rapidly. Also, the control voltage Vc is a ground voltage. Therefore, the sub switching element 60S is turned off, and the supply voltage Vi is applied to the source and the gate of the main switching element 60M. As a result, the main switching element 60M is turned off, and the switch circuit 60 is turned off. That is, the load 88 is disconnected from the capacitor 20 and charging of the capacitor 20 starts again.

  Between T3 and T4, charging of the capacitor 20 continues, and at T4, the supply voltage Vi again becomes the start voltage VH. After T2, the circuit of the first embodiment is in a steady state in which the state between T2 and T4 is repeated. The circuit of Example 1 operates properly when in steady state.

(Example 2)
In the simulator, the storage circuit 10 of FIG. 2 was constructed as the circuit of the second embodiment to verify the operation. The capacitance value and resistance value of each element in the circuit of Example 2 were as shown in Table 2.

  Based on the resistance values described in Table 2, the start voltage VH, the stop voltage VL, and the combined resistance R were calculated. In this calculation, the influence of the switching element was not considered. As a result of calculation, the start voltage VH was 2.2 V and the stop voltage VL was 0.5 V. That is, the respective gate threshold values VGS (th) of the switching elements are lower than the start voltage VH and higher than the calculated stop voltage VL. The combined resistance R is 3.0 MΩ until the supply voltage Vi falls from the start voltage VH to the stop voltage VL, and during the time the supply voltage Vi increases from the stop voltage VL to the start voltage VH. , Was 3.3 MΩ.

The circuit of the second embodiment was connected between the power supply 82 and the load 88 to verify the operation of the circuit of the second embodiment. In operation verification, eight photovoltaic cells connected in series were used as the power supply 82, and a 2 kΩ resistor was used as the load 88. In each of the photovoltaic cells, the light receiving area was 57.8 cm ² , the open circuit voltage Voc by direct sunlight was 1 V, and the short circuit current Isc by direct sunlight was 500 mA. Light having a spectrum equivalent to that of sunlight was applied from above the photovoltaic cell vertically at an intensity of 30 μW / cm ² , whereby a current of about 150 μA was supplied from the power supply 82 to the circuit of Example 2. The Zener voltage VZ (nominal value: 1.8 V) of the Zener diode Z1 differs depending on the value of the current supplied from the power supply 82, and was 0.4 V under the above-mentioned conditions. Under the above conditions, the supply voltage Vi, the reference voltage Vr (non-inverted voltage Vp), and the detection voltage Vd are determined with the capacitor 20 being empty (ie, the capacitor 20 has a voltage of 0 V) as the start point (0 second). Fluctuations of the reverse voltage Vn, the control voltage Vc, and the output voltage Vo were measured by a simulator.

  The measurement results are shown in FIG. As can be understood by comparing FIG. 10 with FIG. 9, the circuit of the second embodiment operates in the same manner as the circuit of the first embodiment. Specifically, in the circuit of the second embodiment, the switch circuit 60 is maintained in the cut off state from the start point to T2. During this time, at T0, the additional control voltage Vca reaches the additional threshold value TA. At T1, the supply voltage Vi reaches the Zener voltage VZ. The switch circuit 60 becomes conductive at T2 and maintains the conductive state from T2 to T3. The switch circuit 60 is in the cutoff state at T3 and maintains the cutoff state from T3 to T4. After T2, the circuit of the second embodiment is in a steady state in which the state between T2 and T4 is repeated. The circuit of the second embodiment operates properly when in the steady state.

  By applying energy harvesting as a power source of the electronic device, a battery is not required, and various performance improvements such as weight reduction of the electronic device, high environmental resistance, and maintenance free can be achieved. As a result, a new market different from the conventional electronic device market may be built. In order to promote the application of energy harvesting to electronic devices, it is necessary to consider the application of energy harvesting in various industrial fields. Conventionally, the application of energy harvesting has not been studied or the practical application has been abandoned due to various reasons such as the storage circuit being expensive or the voltage or current range generated by the storage circuit not meeting the purpose. Seem.

  On the other hand, according to the present invention, a storage circuit using energy harvesting as a power supply can be formed by a simple combination of a comparator circuit and an additional circuit. That is, according to the present invention, even when the storage circuit is not mass-produced, the storage circuit can be manufactured at low cost. As a result, it becomes easy to construct a storage circuit by a combination of single function elements or to construct an electricity storage circuit using an existing comparator.

  Therefore, even in the case of small and medium-sized enterprises, it becomes possible to develop storage circuits applying energy harvesting, and it becomes possible to study the application of energy harvesting in various industrial fields. In addition, in the case of mass production of storage circuits by a semiconductor manufacturing process, it is possible to manufacture a low cost and small size IC as compared with the case of using the prior art.

  By incorporating the small IC thus manufactured into a low power consumption electronic device such as a microcomputer and a wireless device, the electronic device can directly use the power source by energy harvesting, and the IoT field and M2M The application of energy harvesting in the field is considered to be further promoted.

10, 10A, 10X Storage circuit 12 Power supply line 122 First connection point (connection point)
124 Second connection point (connection point)
126 third connection point (connection point)
128 fourth connection point (connection point)
Reference Signs List 20 capacitor 30, 30B voltage detection circuit 32 detection input terminal 36 reference output terminal 38 detection output terminal 40, 40A, 40X comparison circuit 402 first switching element 404 second switching element 406 third switching element 410 comparator 420 hysteresis circuit 430A delay circuit 42 positive input end 44 negative input end 48 output end 50 additional circuit 50S additional switching element 52 power supply end 54 ground end 56 additional control end 58 additional output end 60 switching circuit 60M main switching element 60S secondary switching element 66 control end R7, R8, R9 resistance (resistance of voltage detection circuit)
R1, R2, R3, R5, R6 resistance (resistance of comparison circuit)
R4 resistance (resistance of additional circuit)
R11, R12, R13 resistance (resistance of switch circuit)
R10 resistance (resistance of delay circuit)
C1 capacitor (capacitor of delay circuit)
Z1 constant voltage element (Zener diode)
D1, D2, D3, D4 Diode 82 Power supply 88 Load Vi Supply voltage Vo Output voltage VZ Zener voltage (predetermined voltage)
Vr reference voltage Vd detection voltage Vp non-inversion voltage Vn inversion voltage Vca additional control voltage Vxa additional applied voltage Vc control voltage Vx applied voltage VH start voltage VL stop voltage TP predetermined threshold TA additional threshold

Claims (4)

A storage circuit that stores power supplied from a power source and supplies it to a load,
The storage circuit includes a power supply line connecting the power supply and the load to each other, a capacitor, a voltage detection circuit, a comparison circuit, an additional circuit, and a switch circuit.
The capacitor is connected to the power supply line, stores the power supplied from the power supply, and applies a supply voltage larger than zero to the power supply line.
The voltage detection circuit has a detection input terminal connected to the power supply line, a reference output terminal for outputting a reference voltage, and a detection output terminal for outputting a detection voltage.
The reference voltage is the supply voltage when the supply voltage is lower than a predetermined voltage, and is the predetermined voltage when the supply voltage is equal to or higher than the predetermined voltage.
The detection voltage varies according to the supply voltage and is lower than the supply voltage,
The comparison circuit is connected to the power supply line, and outputs a positive input terminal connected to the reference output terminal, a negative input terminal connected to the detection output terminal, and an additional control voltage. Have an end with
The additional control voltage is a high voltage according to the supply voltage if the voltage applied to the positive input is higher than the voltage applied to the negative input and is applied to the positive input If the voltage is lower than the voltage applied to the negative input, it is a low voltage according to the ground voltage,
The additional circuit has a power supply end connected to the power supply line and a ground end grounded, and a non-ground state for interrupting between the power supply end and the ground end, and the power supply end Transitioning between the ground terminal and the ground state,
The switch circuit is connected between the capacitor and the load in the power supply line, and transitions between a blocking state in which the load is disconnected from the capacitor, and a conductive state in which the load is conducted to the capacitor. Is possible,
The additional circuit comprises an additional control end connected to the output of the comparison circuit and an additional output for outputting a control voltage.
The control voltage is a high voltage according to the supply voltage when the additional circuit is in the non-ground state, and a low voltage according to the ground voltage when the additional circuit is in the ground state Yes,
The additional circuit is in the non-ground state until the supply voltage rises from zero and an additional applied voltage applied to the additional control terminal in response to the additional control voltage reaches an additional threshold. , And after the additional applied voltage reaches the additional threshold, if the additional applied voltage is higher than the additional threshold, the ground state is taken and the additional applied voltage is the additional threshold. If not lower, take the non-ground state,
The switch circuit has a control end connected to the additional output end,
The switch circuit takes the shut-off state until the supply voltage rises from zero and the applied voltage applied to the control terminal reaches a predetermined threshold according to the control voltage, and the applied voltage is the predetermined After reaching the threshold value, the conductive state is taken if the applied voltage is higher than the predetermined threshold, and the shut off state is taken if the applied voltage is lower than the predetermined threshold,
A storage circuit in which the applied voltage is lower than the predetermined threshold until the supply voltage rises from zero and the additional applied voltage reaches the additional threshold. The storage circuit according to claim 1, wherein
The power supply end of the additional circuit is connected to the power supply line and to the detection output end of the voltage detection circuit,
The storage circuit wherein the control voltage is a high voltage corresponding to the detection voltage when the additional circuit is in the non-ground state. The storage circuit according to claim 2, wherein
The additional circuit comprises an additional switching element consisting of an N-type MOSFET (metal-oxide-semiconductor field-effect transistor),
In the additional switching element, a gate functions as the additional control end, a source functions as the ground end, a drain functions as the power supply end, and the detection output end of the voltage detection circuit And between the control end of the switch circuit and
The additional threshold is a threshold of a potential difference between the gate and the source for causing conduction between the source and the drain in the additional switching element.
The switch circuit includes a main switching element formed of a P-type MOSFET and a sub switching element formed of an N-type MOSFET.
In the main switching element, a source is connected to the power supply side of the power supply line, and a drain is connected to the load side of the power supply line.
In the sub switching device, a gate functions as the control end, a source is grounded, and a drain is connected to the source of the main switching device via two resistors.
The gate of the main switching element is connected between the two resistors,
The storage circuit, wherein the predetermined threshold is a threshold of a potential difference between the gate and the source for electrically connecting the source and the drain in the sub switching element. A storage circuit according to any one of claims 1 to 3, wherein
The storage circuit whose said predetermined threshold value is more than the said additional threshold value.

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