JP2013096112A - Power supply circuit for power generation type faucet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply circuit for a power generation type faucet, which is easily formed to consistently store power while taking overdischarge countermeasures for a lithium ion capacitor.SOLUTION: A power supply circuit 1 for the power generation type faucet includes a generator 60 for generating power with the flow of water flowing in a water supply pipe, storage means for storing a current generated by the generator 60, and a control part 40 for controlling water discharge with the power stored in the storage means. A lithium ion capacitor 75 is used as the storage means. As selector means for connecting/disconnecting the lithium ion capacitor 75 to/from the control part 40, a FET 30 is provided. During disconnecting the lithium ion capacitor 75 from the control part 40, the current generated by the generator 60 using a parasitic diode of the FET 30 flows into the lithium ion capacitor 75.

Description

  The present invention relates to a power supply circuit for a power generation faucet.

  In recent water supply apparatuses, an automatic faucet that detects a hand put out in the vicinity of the faucet outlet by a sensor provided in the vicinity of the faucet and automatically discharges water from the outlet is increasing. Moreover, as such an automatic faucet, it has a generator that generates electricity by rotating a water wheel provided in a water discharge path by a water flow, and a capacitor that stores a current generated by the generator, and the electric power stored by the capacitor Some use a solenoid valve to operate. Furthermore, in such an automatic water faucet, a primary battery is provided as a backup means for electric power, and when the amount of electricity stored in the capacitor is small, the power source can be switched between the capacitor and the primary battery by a switching circuit. Some have.

  For example, the water supply control device described in Patent Literature 1 includes a thermoelectric generator as a power generation member, a primary battery that is used by switching to this, and a switching circuit that switches a power supply circuit. In this water supply control device, the switching circuit is configured by a transistor such as an FET, and the power source connected to the control unit is switched between the thermoelectric generator and the primary battery by operating the FET based on a signal from the control unit.

Japanese Patent Laid-Open No. 6-116991

  Here, in recent years, an apparatus using a lithium ion capacitor as an electric storage means for storing electric current is increasing. This lithium ion capacitor has a low series equivalent resistance compared to an electric double layer capacitor that has been used more frequently as a power storage means than before, so that the stored power can be used efficiently, and the leakage current is electrically reduced. Since it is smaller than a double layer capacitor, self-discharge is less than that of an electric double layer capacitor. In addition, since the amount of electricity stored per volume is larger than that of an electric double layer capacitor, the lithium ion capacitor has a higher electricity storage efficiency and performance for effectively using the stored electric power than an electric double layer capacitor. It has become.

  However, in the lithium ion capacitor, the upper limit value and the lower limit value of the working voltage are both limited, and the lithium ion capacitor may be damaged if the voltage exceeds the range. For this reason, when using a lithium ion capacitor as an electrical storage means, management of the voltage stored is very important. In this way, when using a lithium ion capacitor that is a power storage means that can efficiently use the power generated by the generator, measures such as overdischarge are necessary, and the lithium ion capacitor is used for high reliability. A simpler circuit has been desired.

  The present invention has been made in view of the above, and provides a power circuit for a power generation faucet that can easily obtain a circuit that can always store electricity while taking measures against overdischarge of a lithium ion capacitor. For the purpose.

  In order to solve the above-described problems and achieve the object, the power supply circuit of the power generation type faucet according to the present invention includes a generator that generates power by the flow of water flowing through a water supply pipe, and a current generated by the generator. In a power supply circuit for a power generation faucet comprising a power storage means for storing water and a control unit for controlling water discharge by the power stored in the power storage means, a lithium ion capacitor is used as the power storage means, and the lithium ion A field effect transistor is provided as switching means for switching between connection and disconnection between the capacitor and the control unit, and the field effect transistor has when the lithium ion capacitor is disconnected from the control unit by the field effect transistor. A current generated by the generator by a parasitic diode is caused to flow through the lithium ion capacitor.

  In the power generation faucet power circuit, the field effect transistor is preferably p-type, the source electrode is connected to the lithium ion capacitor side, and the drain electrode side is connected to the voltage regulator circuit side. .

  The power supply circuit of the power generation faucet according to the present invention has an effect that a circuit capable of always storing electricity can be easily obtained while taking measures against overdischarge of the lithium ion capacitor.

FIG. 1 is a schematic diagram illustrating a configuration example of a power supply circuit of a power generation faucet according to an embodiment. FIG. 2 is an explanatory diagram showing the correlation between the FET shown in FIG. 1 and other devices. FIG. 3 is a detailed view of the FET shown in FIG. FIG. 4 is a perspective view of a power supply circuit unit including the power supply circuit shown in FIG. FIG. 5 is a perspective view of the lithium ion capacitor shown in FIG. FIG. 6 is an explanatory diagram showing a non-conducting state of the FET. FIG. 7 is an explanatory diagram showing a state in which the FET is conductive. FIG. 8 is a schematic diagram showing a comparative example in the case where an FET is not used as the switching means.

  Hereinafter, embodiments of a power supply circuit for a power generation faucet according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

Embodiment
FIG. 1 is a schematic diagram illustrating a configuration example of a power supply circuit of a power generation faucet according to an embodiment. The power supply circuit 1 shown in the figure is a circuit of an automatic faucet that detects a hand put out in the vicinity of the faucet outlet by a detection sensor 44 provided in the vicinity of the faucet and automatically discharges water from the outlet. It is configured. The automatic faucet is a power generation type that switches between water discharge and water stop by driving a water stop valve 85 that is an electromagnetic valve with a current generated by a generator 60 that generates power by the flow of water flowing through a water supply pipe. It is a faucet. The generator 60 has a water wheel that rotates by the flow of water in a water supply pipe through which water discharged from the water discharge port flows, and generates electricity by rotating the water wheel by the flow of water.

  The power supply circuit 1 has power storage means for storing the current generated by the generator 60, and a lithium ion capacitor 75 is used as the power storage means. The water discharge valve 85 is driven by the electric power stored in the lithium ion capacitor 75. Furthermore, an auxiliary battery 80 is connected to the power supply circuit 1 as an auxiliary power source when the amount of electricity stored in the lithium ion capacitor 75 is reduced. The water valve 85 is driven by electric power from the auxiliary battery 80.

  The generator 60, the lithium ion capacitor 75, the auxiliary battery 80, and the water discharge valve 85 are each connected to an electric circuit by a detachable connector. That is, the generator 60 is detachably attached to the circuit by the generator connector 61, and the lithium ion capacitor 75 is detachably provided by the storage element connector 76. Is detachably disposed by an auxiliary battery connector 82, and the water discharge valve 85 is detachably disposed by a water discharge valve connector 86. The generator 60, the lithium ion capacitor 75, the auxiliary battery 80, and the water discharge valve 85 are provided as a part of the power supply circuit 1 according to the present embodiment by being connected to the circuit by connectors as described above. Yes. Although various batteries can be selected as the auxiliary battery 80, in this embodiment, two manganese dry batteries are assumed to be in series (operating voltage 2.0V to 3.0V).

  The power supply circuit 1 includes a diode bridge 10 that is a rectifier circuit that rectifies a current generated by the generator 60. That is, the generator 60 generates alternating current, whereas the lithium ion capacitor 75 stores or discharges direct current. Moreover, each part, such as the water discharge valve 85, is also operated by a direct current. For these reasons, the power supply circuit 1 is provided with a diode bridge 10 as a rectifier circuit that rectifies an alternating current generated by the generator 60 to make a direct current. The diode bridge 10 includes a rectifier diode 12 that is a semiconductor diode generally used for rectifying current and a Schottky barrier diode 14 that uses a rectifying action of a Schottky junction between a metal and a semiconductor. It is comprised by using one by one.

  Further, the lithium ion capacitor 75 needs to be used in a charged state where the operating voltage is within a predetermined range. For this reason, the power supply circuit 1 has an upper limit side voltage determination unit 20 that determines whether or not the use voltage is an upper limit value of the usable voltage of the lithium ion capacitor 75, and a lower limit side that determines whether or not the use voltage is a lower limit value. Voltage determination unit 25.

  Both the upper limit voltage determination unit 20 and the lower limit voltage determination unit 25 are provided by a voltage detector that switches signals at a predetermined voltage. Specifically, the lithium ion capacitor 75 needs to be used in a charged state where the operating voltage is approximately in the range of 2.2V to 3.8V. For this reason, in the power supply circuit 1 according to the present embodiment, the determination value of the voltage is set with a margin in consideration of safety, and the upper limit voltage determination unit 20 uses the one whose output signal is switched at 3.5 V, As the lower limit side voltage determination unit 25, the one whose output signal is switched at 2.5V is used.

  The upper limit voltage determination unit 20 and the lower limit voltage determination unit 25 are connected to a switching unit that switches the flow of current in the circuit based on signals from these determination units. That is, the upper limit side voltage determination unit 20 is connected to an upper limit side switching unit 21 that switches a current flow based on a signal from the upper limit side voltage determination unit 20. A lower limit side switching unit 26 that switches a current flow based on a signal from the voltage determination unit 25 is connected. Both the upper limit side switching unit 21 and the lower limit side switching unit 26 are provided by an n-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and the upper limit side switching unit 21 and the lower limit side switching unit 26 Are connected to the upper limit voltage determination unit 20 and the lower limit voltage determination unit 25.

  Further, the lower limit side switching unit 26 is a p-type switching unit that switches between connection and disconnection between the lithium ion capacitor 75 and the control unit 40 that controls water discharge by the electric power stored in the lithium ion capacitor 75. A MOS-FET (Field-Effect Transistor) 30 is connected. The FET 30 has a source electrode connected to the lithium ion capacitor 75 side, a drain electrode side connected to the cathode side of the rectifier diode 12, and an output of the lower limit side switching unit 26 connected to the gate electrode of the FET 30.

  FIG. 2 is an explanatory diagram showing the correlation between the FET shown in FIG. 1 and other devices. FIG. 3 is a detailed view of the FET shown in FIG. Specifically, the FET 30 has a source electrode 31 connected to the + (plus) side of the lithium ion capacitor 75. The drain electrode 32 is connected to the diode bridge 10 that rectifies the alternating current generated by the generator 60 into direct current, and the drain electrode 32 is further connected to the voltage adjustment circuit 52 for the lithium ion capacitor. Further, the gate electrode 33 of the FET 30 is connected to the output of the lower limit side switching unit 26. The FET 30 provided in this way is composed of a p-type semiconductor and an n-type semiconductor. Further, the FET 30 has a parasitic diode 35 which is a built-in diode built in the FET 30.

  The lower limit side voltage determination unit 25 is connected to the voltage lower limit transmission unit 28 in addition to the lower limit side switching unit 26. The voltage lower limit transmission unit 28 is provided by an n-type MOSFET similarly to the lower limit side switching unit 26, and the lower limit side voltage determination unit 25 is connected to the gate electrode of the voltage lower limit transmission unit 28. Further, the drain electrode of the voltage lower limit transmission unit 28 is connected to the control microcomputer unit 49, so that the control microcomputer unit 49 changes the signal state of the lower limit side voltage determination unit 25 to the voltage lower limit transmission unit 28. Can be detected via

  The control microcomputer unit 49 is configured as an electronic control unit, and the hardware configuration includes a processing unit having a CPU (Central Processing Unit), a storage unit such as a RAM (Random Access Memory), and the like. Since it is the structure of this, description is abbreviate | omitted.

  The control microcomputer unit 49 uses the power supplied from the voltage adjustment circuit 52 for the lithium ion capacitor or the voltage adjustment circuit 50 for the auxiliary battery, which is a voltage adjustment circuit for adjusting the voltage of the electric power stored in the lithium ion capacitor 75. To drive. Further, the water discharge valve 85 can also be driven by electric power supplied from the voltage adjustment circuit 52 for the lithium ion capacitor or the voltage adjustment circuit 50 for the auxiliary battery. Among them, the voltage adjustment circuit 52 for the lithium ion capacitor is a voltage adjustment circuit that adjusts the voltage output from the lithium ion capacitor 75 to a voltage used for controlling water discharge in the control microcomputer unit 49, and is used for the auxiliary battery. The voltage adjustment circuit 50 is a voltage adjustment circuit that adjusts the voltage output from the auxiliary battery 80 to a voltage used for controlling water discharge in the control microcomputer unit 49. Further, the control microcomputer unit 49, the lithium ion capacitor voltage adjustment circuit 52, and the auxiliary battery voltage adjustment circuit 50 are all included in the control unit 40 and constitute the control unit 40.

  The water stop valve 85 is driven by the water stop valve control circuit 55. The water discharge valve control circuit 55 includes a plurality of open / close control transistors 56. Further, the discharge water valve control circuit 55 has a plurality of open / close control diodes 57 for absorbing the back electromotive voltage. A control microcomputer unit 49 is connected to the base electrode of the open / close control transistor 56, and the control microcomputer unit 49 controls the plurality of open / close control transistors 56 to discharge from the voltage adjustment circuit 52 for the lithium ion capacitor. The flow path of the current flowing through the water stop valve 85 can be switched. Thereby, it is possible to switch opening and closing of the water stop valve 85.

  The water stop valve 85 is a latch type solenoid valve. For this reason, when the current in the opening direction or the closing direction is supplied to the discharge water valve 85 and the discharge water valve 85 is driven, the discharge water is stopped even if the current to the discharge water valve 85 is interrupted thereafter. The valve 85 is maintained in an open state or a closed state.

  Further, the control unit 40 is provided with a detection sensor 44 for detecting a hand put out in the vicinity of the water outlet of the faucet. The detection sensor 44 includes a sensor light emitting unit 45 formed of a light emitting diode, and a photo sensor. And a sensor light receiving unit 46 made of a diode. Among these, the sensor light emission part 45 light-emits intermittently with the voltage adjusted with the voltage adjustment circuit 52 for lithium ion capacitors, or the voltage adjustment circuit 50 for auxiliary batteries, and irradiates the water outlet vicinity. Further, the sensor light receiving unit 46 is connected to the control microcomputer unit 49, and the reflected light when the light from the sensor light emitting unit 45 irradiated to the hand near the water outlet is reflected by the hand is used. A current flows by receiving light. The control microcomputer unit 49 detects that the hand has been put out near the water outlet by detecting this current.

  The power generation circuit 1 of the power generation type faucet according to this embodiment is configured as described above, and the operation thereof will be described below. FIG. 4 is a perspective view of a power supply circuit unit including the power supply circuit shown in FIG. FIG. 5 is a perspective view of the lithium ion capacitor shown in FIG. The power supply circuit 1 is configured as a power supply circuit unit 5 that is one unit including the generator 60 and the lithium ion capacitor 75. The lithium ion capacitor 75 can be attached to and detached from the power supply circuit unit 5 by attaching and detaching the storage element connector 76. When the product is stored (before mounting), the lithium ion capacitor 75 is separated from the power supply circuit 1 and packed in a moisture-proof bag or the like in order to prevent discharge due to dust or moisture. At the time of installation of the power supply circuit 1, that is, at the time of construction, the lithium ion capacitor 75 is taken out from a packaged bag or the like and connected to the circuit. The lithium ion capacitor 75 is held by a holder 77 and sealed with an O-ring 78. Connect with moisture-proof measures.

  Further, the auxiliary battery 80 can be used as an auxiliary power source by being housed in the auxiliary battery case 81, and the auxiliary battery case 81 can also be used as a power circuit by attaching / detaching the auxiliary battery connector 82. The unit 5 is detachable. The lithium ion capacitor 75 is configured such that the current path of the lithium ion capacitor 75 to the circuit is not formed unless the auxiliary battery connectors 82 are connected to each other.

  When the power supply circuit unit 5 is completely attached and before water discharge, the input voltage of the lower limit side voltage determination unit 25, that is, the cathode side voltage of the rectifier diode 12 is 0, so the lower limit side voltage determination unit 25 does not operate and the lower limit side The output voltage of the voltage determination unit 25 is also zero. Therefore, since there is no conduction from the drain electrode to the source electrode of the lower limit side switching unit 26 and no conduction from the source electrode to the drain electrode of the FET 30, the lithium ion capacitor 75 is disconnected from the circuit. Therefore, at this time, the auxiliary battery voltage adjustment circuit 50 is operated by the electric power from the auxiliary battery 80 and the control unit 40 is activated. Thereafter, until the first water discharge, the control microcomputer 49 and the water discharge valve control circuit 55 are driven by the electric power from the auxiliary battery 80.

  Further, until the first water discharge, the detection sensor 44 is also driven by the electric power from the auxiliary battery 80. When the user of the automatic water faucet puts his hand near the water discharge port, the light from the sensor light emitting unit 45 hits the hand, Light is reflected by hand. When the reflected light reflected by the hand is received by the sensor light receiving unit 46 in this way, the control microcomputer unit 49 detects that the hand is being pushed out.

  The control microcomputer unit 49 that has detected that the hand is being inserted transmits a control signal in a direction to open the discharge water valve 85 to the open / close control transistor 56 of the discharge water valve control circuit 55. Thereby, the current in the direction in which the stop water valve 85 opens flows through the stop water valve 85. The current in this case is also supplied from the auxiliary battery 80, and the water discharge valve 85 is driven by this current to open. When the water stop valve 85 is opened, water flows downstream from the water stop valve 85 in the flow direction of the water flowing through the water supply pipe, and this water is discharged from the water outlet of the automatic water faucet. The power supply to the water discharge valve 85 is controlled to stop after several tens of ms. Since a latch valve is used for the water discharge valve 85, the water discharge valve 85 remains open even after the power supply is stopped. That is, it is kept open until power for that is supplied at the time of water stoppage.

  When the first water discharge starts, the generator 60 rotates by the flow of water flowing in the water supply pipe, and the generator 60 rotates to generate power, and the input voltage of the lower limit side voltage determination unit 25 increases due to the power generation of the generator 60. When the input voltage of the lower limit side voltage determination unit 25 rises and exceeds the lower limit voltage, the output of the lower limit side voltage determination unit 25 becomes H, and the source electrode and the drain electrode of the FET 30 are electrically connected. At this time, if the stored voltage of the lithium ion capacitor 75 is equal to or higher than the set lower limit voltage, the output H of the lower limit voltage determination unit 25 is maintained even after the generator 60 is stopped, and the conduction of the FET 30 is continued.

  When the FET 30 is turned on, power is supplied from the lithium ion capacitor 75 to the voltage adjustment circuit 52 for the lithium ion capacitor, and the control microcomputer unit 49 and the water discharge valve control circuit 55 are driven by the stored power of the lithium ion capacitor 75. . At the same time, the output from the lower limit side voltage determination unit 25 is also transmitted to the voltage lower limit transmission unit 28, and the control microcomputer unit 49 confirms that the lithium ion capacitor 75 is sufficiently charged by the signal from the voltage lower limit transmission unit 28. It detects and stops the voltage adjustment circuit 50 for auxiliary batteries. That is, the power supply from the auxiliary battery 80 is stopped.

  In general, the equivalent series resistance of the lithium ion capacitor 75 is smaller than the equivalent series resistance of the auxiliary battery 80. For this reason, if the output voltage of the voltage adjustment circuit 52 for the lithium ion capacitor is equal to or lower than the output voltage of the voltage adjustment circuit 50 for the auxiliary battery, the circuit does not have to be stopped without stopping the voltage adjustment circuit 50 for the auxiliary battery. Most of the electric power is supplied from the lithium ion capacitor 75. Therefore, the stop command from the control microcomputer unit 49 to the auxiliary battery voltage adjustment circuit 50 can be omitted.

  When the generated power is larger than the power consumed by the power supply circuit 1, the stored voltage of the lithium ion capacitor 75 gradually increases, and eventually the stored voltage of the lithium ion capacitor 75 exceeds the set upper limit during the power generation of the generator 60. That is, when the FET 30 is conductive, the stored voltage of the lithium ion capacitor 75 is equal to the cathode side voltage of the rectifier diode 12, that is, the input voltage of the upper limit side voltage determination unit 20. Whether or not the storage voltage exceeds the set upper limit can be determined by the upper limit side voltage determination unit 20.

  When the storage voltage of the lithium ion capacitor 75 exceeds the set upper limit and the output of the upper limit side voltage determination unit 20 becomes H, the upper limit side switching unit 21 is turned on, and the power of the generator 60 is transferred from the diode 15 to the upper limit side switching unit 21. And is consumed in a path flowing to the Schottky barrier diode 14, and charging to the lithium ion capacitor 75 is stopped. In this case, since the FET 30 is conductive, power supply from the lithium ion capacitor 75 to the upper limit side voltage determination unit 20 and the voltage adjustment circuit 52 for the lithium ion capacitor is continued.

  When the generated power is smaller than the power consumption in the power supply circuit 1, the stored voltage of the lithium ion capacitor 75 gradually decreases and eventually falls below the set lower limit. Then, since the output of the lower limit side voltage determination unit 25 becomes L, the lower limit side switching unit 26 becomes non-conductive, the non-conductive state is also established between the source electrode and the drain electrode of the FET 30, and the lithium ion capacitor 75 is disconnected from the circuit. Then, since the input of the lower limit side voltage determination unit 25 is also lost, the output of the lower limit side voltage determination unit 25 is held at L, and the non-conduction of the FET 30 is continued. That is, the separation of the lithium ion capacitor 75 is maintained without using any power of the lithium ion capacitor 75, and this state is maintained even if the power of the auxiliary battery 80 is exhausted.

  At the same time, the control microcomputer unit 49 detects that the lithium ion capacitor 75 has been disconnected from the circuit by the power supply switching transmission unit 28 and activates the auxiliary battery voltage adjustment circuit 50. Thereby, the operation can be continued by the electric power supplied from the auxiliary battery 80.

  Here, even when the lower limit side switching unit 26 and the FET 30 are non-conductive, there is a possibility that a slight discharge, for example, nA level may continue due to the insulation resistance of the circuit board and the leakage current of the element. Then, the influence is mitigated by the diode 17 disposed in the path between the control microcomputer unit 49 and the FET 30.

  Therefore, if the auxiliary battery 80 is healthy, approximately 2.3 V, which is obtained by subtracting the forward voltage drop 0.7 V of the diode 17 from the voltage 3.0 V of the auxiliary battery 80, is supplied to the lithium ion capacitor 75. Therefore, while the auxiliary battery 80 is healthy, the voltage of the lithium ion capacitor 75 does not fall below the use lower limit voltage of 2.2 V of the element.

  Further, since the FET 30 includes the parasitic diode 35, the FET 30 can pass a current in the forward direction in the parasitic diode 35 even when the FET 30 is non-conductive. FIG. 6 is an explanatory diagram showing a non-conducting state of the FET. When the lower limit side switching unit 26 is nonconductive, the FET 30 has no potential difference between the source electrode and the gate electrode, and the direction from the source electrode to the drain electrode is nonconductive. That is, the FET 30 is an element that conducts between the source electrode and the drain electrode when the voltage of the gate electrode is sufficiently lower than the voltage of the source electrode. For this reason, when the output from the lower limit side voltage determination unit 25 becomes L and the lower limit side switching unit 26 becomes non-conductive, a large potential difference does not occur between the source electrode and the gate electrode of the FET 30. The FET 30 becomes non-conductive.

  When the FET 30 becomes non-conductive in this way, the lithium ion capacitor 75 of the source electrode and the control microcomputer unit 49 on the drain electrode side due to the current flow when the FET 30 is conductive are disconnected, but the FET 30 has a parasitic diode 35. doing. For this reason, a current can flow in the forward direction of the parasitic diode 35. Specifically, the parasitic diode 35 has a forward direction from the drain electrode side to the source electrode side. Accordingly, the non-conducting FET 30 cannot flow current from the source electrode side to the drain electrode side, but can flow through the parasitic diode 35 from the drain electrode side to the source electrode side.

  That is, the FET 30 can indicate normal operation by the open / close switch 93 that switches between connection and disconnection of the drain electrode and the source electrode, and the parasitic diode 35 is provided in parallel with the open / close switch 93 and is connected to the drain electrode side. This can be indicated by a diode 94 whose direction from the source electrode side to the source electrode side is a forward direction. For this reason, when the FET 30 is in a non-conductive state by the open / close switch 93 and the diode 94, the open / close switch 93 is opened, and the drain electrode and the source electrode are connected by the diode 94 arranged in parallel to the open / close switch 93. Connected. In this case, since current cannot flow through the open / close switch 93, the open / close switch 93 shuts off the drain electrode and the source electrode. However, the diode 94 allows current to flow from the drain electrode side to the source electrode side. It becomes possible.

  Therefore, when the FET 30 becomes non-conductive, the lithium ion capacitor 75 connected to the source electrode side of the FET 30 does not discharge to the voltage adjustment circuit 52 side for the lithium ion capacitor. The current being supplied is not supplied to the circuit side. On the other hand, current can flow from the drain electrode side to the source electrode side via the parasitic diode 35 from the diode bridge 10 side connected to the drain electrode side of the FET 30 to the lithium ion capacitor 75. Thereby, even when the FET 30 is non-conductive, the current generated by the generator 60 can be stored by the lithium ion capacitor 75. As described above, when the FET 30 cuts off the lithium ion capacitor 75 and the voltage adjustment circuit 52 for the lithium ion capacitor, the current generated by the generator 60 by the parasitic diode 35 of the FET 30 is supplied to the lithium ion capacitor 75 and stored.

  When the connection between the source electrode and the drain electrode of the FET 30 is non-conductive, the circuit is driven by the power supplied from the auxiliary battery 80 to open the water discharge valve 85, and when water discharge is performed, the generator 60 Output voltage is generated. This voltage is rectified and generated on the cathode side of the rectifier diode 12, passes through the parasitic diode 35 (reference numeral 94 in FIG. 6) in the FET 30, and is stored in the lithium ion capacitor 75.

  That is, even when the source electrode and the drain electrode of the FET 30 are not conductive, the drain electrode and the source electrode are conductive through the parasitic diode 35, and the lithium ion capacitor 75 is charged. If the direction from the source electrode to the drain electrode of the FET 30 is in a non-conductive state and the generator 60 is charged, the stored voltage of the lithium ion capacitor 75 may exceed the lower limit voltage at a certain time. In that case, the same situation as in “first water discharge after completion of attachment” occurs, and conduction between the source electrode and the drain electrode of the FET 30 is restored.

  FIG. 7 is an explanatory diagram showing a state in which the FET is conductive. When the input voltage of the lower limit side voltage determination unit 25 exceeds the lower limit voltage, the lower limit side switching unit 26 conducts, and the gate electrode side of the FET 30 is connected to the ground, thereby reducing the voltage on the gate electrode side of the FET 30. Let For this reason, when the output from the lower limit side voltage determination unit 25 becomes H and the lower limit side switching unit 26 becomes conductive, the source electrode and the drain electrode of the FET 30 become conductive. When the FET 30 is thus conducted, the lithium ion capacitor 75 on the source electrode side of the FET 30 and the voltage adjustment circuit 52 for the lithium ion capacitor on the drain electrode side are connected, and the current stored in the lithium ion capacitor 75 is supplied to the circuit. Will be. That is, the FET 30 in the conductive state can be indicated by the open / close switch 93 and the diode 94 that are closed. In this case, a current can flow in either direction as necessary between the drain electrode side and the source electrode side of the FET 30.

  As a result, the stored voltage of the lithium ion capacitor 75 is kept within a predetermined range, and overcharge and overdischarge of the lithium ion capacitor 75 are suppressed. Further, even when the lithium ion capacitor 75 is disconnected from the circuit due to the low voltage, the lithium ion capacitor 75 can be charged.

  The output from the lower limit side voltage determination unit 25 is also transmitted to the voltage lower limit transmission unit 28. Similarly to the lower limit side switching unit 26, the voltage lower limit transmission unit 28 becomes conductive when the output from the lower limit side voltage determination unit 25 is H, and becomes nonconductive when the output is L. Further, since the drain electrode side of the lower limit side switching unit 26 is connected to the control microcomputer unit 49 and the source electrode side is connected to the ground, the control microcomputer unit 49 is connected to the voltage lower limit transmission unit 28. Thus, the output state of the lower limit side voltage determination unit 25 can be detected. For this reason, it is possible to detect that the voltage detected by the lower limit side voltage determination unit 25 is 2.5 V or less through detection that the voltage lower limit transmission unit 28 is OFF.

When the connection of the lithium ion capacitor 75 to the power supply circuit 1 is restored, more strictly,
1. H determination of the lower limit side voltage determination unit 25 is performed.
2. The FET 30 becomes conductive.
3. The input of the lower limit side voltage determination unit 25 decreases by the voltage drop of the parasitic diode 35 of the FET 30.
4). The lower limit side voltage determination unit 25 determines L.
5. The FET 30 becomes non-conductive.
6). The input of the lower limit side voltage determination unit 25 rises and makes an H determination.
There is a possibility to repeat. For this reason, the determination by the lower limit side voltage determination unit 25 is provided with hysteresis. For example, the lower limit side voltage determination unit 25 shifts the determination from L to H when the input voltage becomes 2.6 V or more, and shifts from H to L when the input voltage becomes 2.4 V or less.

  When the power supply circuit 1 does not want to interrupt the control of the circuit regardless of the stored voltage of the lithium ion capacitor 75, such as when the discharge valve 85 is being driven, the control microcomputer unit 49 maintains the conduction of the FET 30, Various controls are possible such as increasing the reliability of the control operation.

  The power generation faucet power supply circuit 1 according to the above embodiment switches between connection and disconnection of the lithium ion capacitor 75 and the control microcomputer unit 49, that is, connection and disconnection between the lithium ion capacitor 75 and the control unit 40. The FET 30 is used as the switching means, and when the lithium ion capacitor 75 and the control unit 40 are shut off by the FET 30, the current generated by the generator 60 by the parasitic diode 35 is supplied to the lithium ion capacitor 75 and stored, so the power storage is continued. It is possible to easily obtain a circuit to perform.

  FIG. 8 is a schematic diagram showing a comparative example in the case where an FET is not used as the switching means. In this example, a latching relay 96 that switches a current flow from the generator 60 to the lithium ion capacitor 75 and a switching control transistor 97 that controls the latching relay 96 are used. In this case, the number of parts increases, and the control unit 40 must control the plurality of switching control transistors 97 to switch the state in which current flows, so that the circuit becomes complicated.

  On the other hand, in the power supply circuit 1 according to the present embodiment, the number of components can be reduced by using the FET 30 as the switching means, and the storage voltage of the lithium ion capacitor 75 can be reduced without being controlled by the control unit 40. Accordingly, it is possible to continuously store electricity while suppressing discharge. As a result, it is possible to easily obtain a circuit that can always store power while taking measures against overdischarge of the lithium ion capacitor 75.

  In addition, since the lithium ion capacitor 75 has low series equivalent resistance and leakage current compared to the EDLC (electric double layer capacitor) that has been used for similar applications, the voltage fluctuation during large current storage / discharge is small. Accurate measurement of the storage voltage is possible, and the influence on the overvoltage prevention circuit and the like can be reduced. In addition, the large-capacity electrolytic capacitor provided for the purpose of stabilizing the output voltage can be reduced or omitted. As a result, the generated power can be used effectively with a simple circuit.

  Further, since the lithium ion capacitor 75 is connected at the construction site, it is possible to prevent the lithium ion capacitor 75 from being overdischarged during distribution and becoming unusable. As a result, the reliability of the product can be improved.

  Further, since the auxiliary battery connector 82 is connected to the connection of the lithium ion capacitor 75, the lithium ion capacitor 75 is not connected to the circuit before the auxiliary battery 80 is attached. The chance of discharge can be reduced. That is, even if the lithium ion capacitor 75 is discharged to the allowable lower limit, the power supply circuit 1 is operated by the auxiliary battery 80. In this case, the auxiliary battery 80 is not operated until the amount of power stored in the lithium ion capacitor 75 is recovered by power generation by water discharge. Since it is consumed, it is preferable to avoid unnecessary discharge of the lithium ion capacitor 75 as much as possible. For this reason, unnecessary discharge can be avoided by reducing the chance of discharge of the lithium ion capacitor 75 due to careless attachment such as not attaching the auxiliary battery 80, for example. As a result, the reliability of the product can be improved more reliably.

  Further, in the power supply circuit 1 described above, when the voltage of the lithium ion capacitor 75 is lowered, only the connection with the control unit 40 side is cut off, but when the voltage of the lithium ion capacitor 75 is lowered, You may make it alert | report an abnormality to a user. Thus, the user can continue to use for a long time without knowing the abnormality, and the lithium ion capacitor 75 can be prevented from being damaged due to overdischarge due to the continuous slight discharge.

  The power supply circuit 1 described above is a power supply circuit 1 for an automatic faucet that automatically discharges water by detecting that a hand has been inserted, and is described assuming a faucet used in a washstand or the like. However, the power generation faucet that controls water discharge by the power supply circuit 1 may be other than this. The power generation faucet may be, for example, a urinal that automatically detects a person with the detection sensor 44 and performs cleaning. The power generation type faucet controlled by the power supply circuit 1 can be used as long as it detects the detection object by the detection sensor 44 and switches water discharge or water stoppage through the water supply pipe according to the state of the detection object. Does not matter.

1 Power supply circuit 5 Power supply circuit unit 10 Diode bridge (rectifier circuit)
DESCRIPTION OF SYMBOLS 12 Rectifier diode 14 Schottky barrier diode 20 Upper limit side voltage determination part 21 Upper limit side switching part 25 Lower limit side voltage determination part 26 Lower limit side switching part 28 Voltage lower limit transmission part 30 FET (field effect transistor)
31 Source electrode 32 Drain electrode 33 Gate electrode 35 Parasitic diode 40 Control unit 44 Detection sensor 49 Control microcomputer unit 50 Auxiliary battery voltage adjustment circuit 52 Lithium ion capacitor voltage adjustment circuit 55 Water discharge valve control circuit 60 Generator 61 Power generation Machine connector 75 Lithium ion capacitor (electric storage means)
80 Auxiliary battery 85 Water stop valve (solenoid valve)

Claims (2)

A generator that generates electricity by the flow of water flowing through the water supply pipe;
Power storage means for storing current generated by the generator;
A control unit for controlling water discharge by the electric power stored in the power storage means;
In the power circuit of the power generation faucet comprising
Using a lithium ion capacitor as the power storage means,
It has a field effect transistor as a switching means for switching between connection and disconnection of the lithium ion capacitor and the control unit,
When the lithium ion capacitor and the control unit are shut off by the field effect transistor, a current generated by the generator is caused to flow through the lithium ion capacitor by a parasitic diode included in the field effect transistor. Plug power circuit.   2. The power generation faucet according to claim 1, wherein the field effect transistor is p-type, a source electrode is connected to the lithium ion capacitor side, and a drain electrode side is connected to the control unit side. Power supply circuit.

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