JP2012152059A - Power supply circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply circuit for producing electric power capable of operating actual electric circuits with electric power generated by a power generation element that generates minute electric power.SOLUTION: In a power supply circuit, the electric power produced by a power generation element is once stored in a first capacitor C1 through a full-wave rectifier circuit 20, a second capacitor C2 is charged by a charge control circuit 30 using the electric power stored in the first capacitor C1 until the second capacitor gains a voltage necessary for operating a load, and the electric power stored in the second capacitor C2 is supplied to the load by an output control circuit 40. Consequently, by means of the electric power produced by a power generation element for producing minute power, the electric power having a voltage that can operate actual electric circuits is supplied.

Description

  The present invention relates to a power supply circuit used for a power generation element that outputs minute electric power, and more particularly to a power supply circuit that outputs electric power of a voltage necessary for a load.

  Conventionally, a method of supplying electric energy of a predetermined voltage to a load via a rectifier circuit or a smoothing circuit is generally used when generating and using a minute electric power by using a piezoelectric element or an element that converts vibration energy into electric energy. It is.

  As an example of a micro power generation element, for example, a power generation element that generates micro power, such as an electret micro power generation apparatus disclosed in JP 2010-119280 A or JP 2009-77614 A, is known. . Since the electric power generated by such a power generation element is minute AC power, in most cases, the DC voltage is supplied to the load after being rectified and converted to DC. For example, rectification is performed by a half-wave rectifier circuit using diodes or a full-wave rectifier circuit.

JP 2010-119280 A JP 2009-77614 A

  However, when using the electric power generated by the power generation element that generates the minute electric power as described above, only a minute electric power can be obtained only by converting it into direct current by the rectifier circuit. There was a problem that was too small.

  In view of the above problems, the present invention is to provide a power supply circuit capable of obtaining electric power that can operate an actual electric circuit or the like using electric power generated by a power generation element that generates minute electric power.

  In order to solve the above problems, the present invention is a power supply circuit that stores a minute amount of generated power generated by a power generation element and supplies the stored power to a load, and includes a low potential side terminal and a high potential side A first capacitor having a predetermined first capacitance and a power storage means for storing the generated power in the first capacitor; a low potential side terminal; and a high potential side terminal. A second capacitor having a second capacitance larger than one capacitance is connected to the low potential side terminal of the first capacitor and the low potential side terminal of the second capacitor, and the terminal voltage of the first capacitor is predetermined. Until the first threshold voltage of the first capacitor is reached, the first capacitor is turned on and the voltage across the first capacitor becomes the second threshold voltage lower than the first threshold voltage. When power is supplied from the high potential side terminal of the capacitor to the high potential side terminal of the second capacitor and stored in the second capacitor, and the voltage across the first capacitor becomes the second threshold voltage Charging control means for stopping the power supply from the high potential side terminal of the first capacitor to the high potential side terminal of the second capacitor, and the voltage across the terminals of the second capacitor is less than the predetermined second threshold voltage From the second capacitor until it reaches the fourth threshold voltage lower than the third threshold voltage when it reaches a low third threshold voltage and becomes conductive. Output control means for supplying power to the load and for stopping power supply from the second capacitor to the load when the voltage across the second capacitor reaches the fourth threshold voltage. Power supply To propose a road.

  According to the present invention, the electric power generated by the external power generation element by the power storage means is stored in the first capacitor. Further, the charge control means becomes conductive when the voltage across the first capacitor reaches a predetermined first threshold voltage, and the voltage across the first capacitor is greater than the first threshold voltage. Electric power is supplied from the high-potential side terminal of the first capacitor to the high-potential side terminal of the second capacitor until the second threshold voltage is lowered to store the second capacitor. Furthermore, the charge control means stops the power supply from the high potential side terminal of the first capacitor to the high potential side terminal of the second capacitor when the voltage between the terminals of the first capacitor reaches the second threshold voltage. .

  The electric power stored in the second capacitor is supplied to the load by the output control means. At this time, the output control means becomes conductive when the voltage between the terminals of the second capacitor reaches the third threshold voltage lower than the second threshold voltage, and the voltage between the terminals of the second capacitor becomes the third voltage. Power is supplied from the second capacitor to the load until a fourth threshold voltage lower than the threshold voltage is reached, and when the voltage across the second capacitor reaches the fourth threshold voltage, Stop power supply to the load.

  In the power supply circuit of the present invention, the power generated by the power generation element is stored in the first capacitor at one end, and the power necessary for operating the load is obtained by the power stored in the first capacitor. Since the power stored in the second capacitor is supplied to the load after the capacitor is charged, an actual electric circuit or the like can be operated by the power generated by the power generation element that generates the minute power.

The circuit diagram which shows the power supply circuit in one Embodiment of this invention Voltage waveform diagram of power supply circuit in one embodiment of the present invention Voltage waveform diagram of power supply circuit in one embodiment of the present invention Voltage waveform diagram of power supply circuit in one embodiment of the present invention The block diagram which shows the power supply circuit in other embodiment of this invention

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

  In FIG. 1, reference numeral 10 denotes a power supply circuit, which is composed of a full-wave rectifier circuit 20, a first capacitor C1, a charge control circuit 30, a second capacitor C2, and an output control circuit 40. In the present embodiment, the full-wave rectifier circuit 20 and the first capacitor C1 constitute power storage means in the present invention, the charge control circuit 30 constitutes charge control means in the present invention, and the output control circuit 40 outputs in the present invention. A control means is configured. In the present embodiment, the voltage waveform of each component is measured by using a micro power generation element that can obtain power of 4 micro W when a load pure resistance of 80 Mohm is connected.

  The full-wave rectifier circuit 10 is a known diode full-wave rectifier circuit, and includes a capacitor Cp and four rectifier diodes D1 to D4. One end of the capacitor Cp is connected to one input terminal 11a, and the other end of the capacitor Cp is connected to the anode of the diode D2 and the cathode of the diode D4. The anode of the diode D1 and the cathode of the diode D3 are connected to the other input terminal 11b. Further, the cathode of the diode D1 and the cathode of the diode D2 are connected to one terminal of the first capacitor C1, and the anode of the diode D3 and the anode of the diode D4 are connected to the other terminal of the first capacitor C1.

  The charge control circuit 30 includes three PNP transistors TR1 to TR3, one NPN transistor TR4, seven resistors R1 to R7, one diode D5, and two Zener diodes ZD1 and ZD2. The emitter of the transistor TR1 is connected to one end of the resistor R1, one end of the first capacitor C1, one end of the resistor R5, and the emitter of the transistor TR2.

  The base of the transistor TR1 is connected to the other end of the resistor R1 and one end of the resistor R2. The other end of the resistor R2 is connected to the cathode of the Zener diode ZD1, and the anode of the Zener diode ZD1 is connected to the other end of the first capacitor C1. The collector of the transistor TR1 is connected to one end of the resistor R3, one end of the resistor R4, and the anode of the Zener diode ZD2. The other end of the resistor R3 is connected to the other end of the first capacitor C1.

  The collector of the transistor TR2 is connected to one end of the resistor R7, the anode of the diode D5, and the collector of the transistor TR3. The base of the transistor TR2 is connected to the emitter of the transistor TR3. The cathode of the diode D5 is connected to the cathode of the Zener diode ZD2. The other end of the resistor R7 is connected to one end of the second capacitor C2.

  The base of the transistor TR3 is connected to the other end of the resistor R5 and one end of the resistor R6.

  The collector of the transistor TR4 is connected to the other end of the resistor R6, the base of the transistor TR4 is connected to the other end of the resistor R4, and the emitter of the transistor TR4 is the other end of the first capacitor C1 and the other end of the second capacitor C2. It is connected to the.

  The output control circuit 40 includes two PNP transistors TR5 and TR6, one NPN transistor TR7, three Zener diodes ZD3 to ZD5, seven resistors R9 to R15, one linear regulator IC1, two capacitors C3 and C4, and The external control signal input circuit 41 is configured.

  The cathode of the Zener diode ZD3 is connected to one end of the second capacitor C2, one end of the resistor R8, the emitter of the transistor TR5, one end of the capacitor C3, and the input terminal IN of the linear regulator IC1. The anode of the Zener diode ZD3 is connected to the other end of the second capacitor C2, the anode of the Zener diode ZD4, the anode of the Zener diode ZD5, and the GND output terminal 12b.

  The base of the transistor TR5 is connected to the other end of the resistor R8, one end of the resistor R9, and one end of the resistor R15. The collector of the transistor TR5 is connected to the emitter of the transistor TR6 and one end of the resistor R10. The other end of the resistor R9 is connected to the cathode of the Zener diode ZD4.

  The base of the transistor TR6 is connected to the other end of the resistor R10 and one end of the resistor R11. The other end of the resistor R11 is connected to the cathode of the Zener diode ZD5. The collector of the transistor TR6 is connected to one end of the resistor R12.

  The collector of the transistor TR7 is connected to the other end of the resistor R15. The base of the transistor TR7 is connected to the other end of the resistor T12 and one end of the resistor R13, and the emitter of the transistor TR7 is connected to the other end of the resistor R13, one end of the resistor R14, and the enable terminal EN of the linear regulator IC1. Yes. The other end of the resistor R14 is connected to the GND output terminal 12b. The other end of the capacitor C3 is connected to the GND terminal GND and the GND output terminal 12b of the linear regulator IC1.

  The output terminal OUT of the linear regulator IC1 is connected to one end of the capacitor C4 and the output terminal 12a, and the noise reduction terminal NR of the linear regulator IC1 is open.

  The external control signal input circuit 41 includes one N-channel field effect transistor (hereinafter referred to as FET) TR8 and two resistors R16 and R17. The drain of the FET TR8 is connected to the base of the transistor TR7, and the gate of the FET TR8 is connected to one end of the resistor R16 and one end of the resistor R17. The source of the FET TR8 is connected to the other end of the resistor R17 and the GND output terminal 12b. The other end of the resistor R16 is connected to the control signal input terminal 13.

  Next, the operation of the power supply circuit according to the present embodiment having the above configuration will be described with reference to voltage waveform diagrams of FIGS. In the figure, Vc1 is a voltage at one end of the first capacitor C1 when the voltage at the other end of the first capacitor C1 is 0V, and Vc2 is a second voltage when the voltage at the other end of the second capacitor C2 is 0V. The voltage at one end of the capacitor C2, Vo is the voltage output from the output terminal 12a.

  Further, in the present embodiment, when the output of the power generation element is connected to the input terminals 11a and 11b, the pulse that changes between 5V and 7V with a predetermined period T1 (about 1.2 seconds) with respect to the first capacitor C1. An example in which the above-described power generating element that generates a voltage that allows the full-wave rectifier circuit 20 to output a current voltage is used will be described. In the present embodiment, a capacitor having a capacity of 1 μF is used as the first capacitor C1, and a capacitor having a capacity of 10 μF is used as the second capacitor C2. In addition, a power generating element connected to the input terminals 11a and 11b has an output impedance of 4M ohms, and a load connected to the output terminals 12a and 12b uses a 3K ohm pure resistance load.

  The full-wave rectifier circuit 20 inputs the AC voltage generated by the power generation element via the input terminals 11a and 11b and the capacitor Cp, and full-wave rectifies the input AC voltage, and the pulsating voltage with a predetermined period obtained thereby is obtained. The first capacitor C1 is charged by applying to the first capacitor C1.

  Next, the operation of the charge control circuit 30 will be described.

  When the first capacitor C1 is charged by the full-wave rectifier circuit 20 and the voltage across the first capacitor C1 reaches 7V, the transistor TR1 is turned on. That is, the base potential of the transistor TR1 is the Zener potential of the Zener diode ZD1 + the voltage across the resistor R2, and when the voltage across the first capacitor C1 is low, the voltage across the resistor R1 is also low. Therefore, the collector current of the transistor TR1 does not flow very much. When the voltage between the terminals of the first capacitor C1 reaches 7V which is set as the first threshold voltage, the voltage between the base and the emitter of the transistor TR1 becomes high, the collector current of the transistor TR1 flows so much that the terminal of the resistor R3 The voltage increases to a predetermined value. As a result, the base potential of the transistor TR4 becomes a TTL level high level (hereinafter referred to as a high level).

  Thereby, the collector current of the transistor TR1 flows, the voltage between the terminals of the resistor R3 becomes high level, and the transistor TR4 is turned on. When the collector current flows through the transistor TR4, the base of the transistor TR3 becomes a low level (hereinafter referred to as a low level) of the TTL level, and the transistor TR3 is turned on, whereby the transistor TR2 is turned on. When the transistor TR2 is turned on, charging from the first capacitor C1 to the second capacitor C2 is started via the transistor TR2.

  The charging of the first capacitor C1 to the second capacitor C2 proceeds, and the collector current of the transistor TR1 decreases until the voltage of the first capacitor C1 decreases and reaches 5V set as the second threshold voltage. Thus, the transistor TR1 is substantially turned off, but the base potential of the transistor TR4 is maintained at a high level by the diode D5 and the Zener diode ZD2. Further, when the voltage of the first capacitor C1 is lowered, the voltage across the Zener diode ZD2 is maintained at a predetermined value, so that the voltage across the resistor R3 is lowered and the base potential of the transistor TR4 is lowered. Decreases, and the transistor TR4 is substantially turned off. As a result, the transistors TR3 and TR2 are also turned off.

  Next, the operation of the output control circuit 40 will be described.

  The linear regulator IC1 is a well-known regulator, and when the voltage applied to the enable terminal EN is at a high level, the current input to the input terminal IN is output to the output terminal OUT at a constant output voltage and applied to the enable terminal EN. When the applied voltage is low level, the output from the input terminal IN to the output terminal OUT is cut off.

  Resistors R8, R9 and Zener diode ZD4 are provided to turn on transistors TR5, TR6, and resistors R10, R11 and Zener diode ZD5 are provided to turn off transistors TR5, TR6. The operation of the output control circuit 40 based on these is as follows.

  That is, when the second capacitor C2 is charged with a voltage equal to or higher than a predetermined value, a current flows through the Zener diode ZD4 via the resistor R8 according to the charging voltage (voltage between the terminals of the second capacitor C2), and the Zener diode ZD4 The inter-terminal voltage is maintained at a predetermined voltage. The voltage of the second capacitor C2−the voltage between the terminals of the Zener diode ZD4 is applied to the resistors R8 and R9, and the voltage divided by the two resistors R8 and R9 (the transistor TR5 which is the voltage between the terminals of the resistor R8) The collector current of the transistor TR5 flows in response to the voltage between the emitter and base of the second capacitor C2, and the voltage Vc2 between the terminals of the second capacitor C2 reaches 4.8V, which is set as the third threshold voltage, and between the terminals of the resistor R8 When the voltage exceeds a predetermined value, the transistor TR5 is turned on. As a result, current flows through the resistors R10 and R11 and the Zener diode ZD5, and the voltage between the terminals of the Zener diode ZD5 is maintained at a predetermined value, so that the collector current of the transistor TR6 flows according to the voltage between the terminals of the resistor R10, When the voltage between the terminals of the resistor R10 exceeds a predetermined value, the transistor TR6 is turned on. When the transistor TR6 is turned on, current flows through the transistor TR5, the transistor TR6, and the three resistors R12, R13, and R14, and the transistor TR7 is turned on according to the voltage across the resistor R13 so that the voltage of the resistor R13 is The transistors TR7, TR5, and TR6 are turned on until the voltage decreases. At this time, the voltage applied to the enable terminal EN of the linear regulator IC1 is at a high level, and the linear regulator IC1 is energized and energized from the second capacitor C2 to the external load.

  When the voltage Vc2 between the terminals of the second capacitor C2 decreases due to energization from the second capacitor C2 to the load and reaches 3V set as the fourth threshold voltage, the voltage between the terminals of the resistor R10 decreases. Thus, the collector current of the transistor TR6 decreases, and the transistor TR6 is turned off. As a result, the voltage across the resistor R13 drops to turn off the transistor TR7 and the voltage across the resistor R14 drops, causing the voltage applied to the enable terminal EN of the linear regulator IC1 to go low. The linear regulator IC1 is cut off. Further, the transistor TR5 is also turned off after the transistor TR6 is turned off in response to the decrease in the voltage Vc2 between the terminals of the second capacitor C2. The time until the inter-terminal voltage Vc2 of the second capacitor C2 becomes the third threshold voltage (4.8V) from the fourth threshold voltage (3V), that is, the charging time T2 is about 13 seconds.

  The voltage Vo is output to the output terminals 12a and 12b when the linear regulator IC1 is in a conductive state. A voltage of about 3 V is output from the output terminals 12a and 12b for a time T3 (about 17 milliseconds).

  When a high level voltage is applied to the control signal input terminal 13, since the gate voltage of the FETTR8 of the external control signal input circuit 41 is high level, the FETTR8 is turned on, and the drain and source of the FET 18 are almost conductive. Therefore, the base voltage of the transistor TR7 becomes low level, the transistor TR7 is turned off, and the linear regulator IC1 is forcibly cut off. Further, when the control signal input terminal 13 is open or when a low level voltage is applied to the control signal input terminal 13, the gate voltage of the FETTR8 of the external control signal input circuit 41 is low level, so that the FETTR8 Is in an OFF state, and the drain and source of the FET 18 are almost open, so that the base voltage of the transistor TR7 is not changed.

  As described above, the power supply circuit 10 according to the present embodiment stores the power generated by the power generation element in the first capacitor C1 and the voltage necessary for operating the load by the power stored in the first capacitor C1. After the second capacitor C2 is charged to a state where it can be obtained, the electric power stored in the second capacitor C2 is supplied to the load. It can be operated.

  The configuration of the present embodiment described above is an example, and the present invention is not limited to the configuration of the rule embodiment. For example, as shown in FIG. 5, when two or more power generation elements are provided to charge one second capacitor C2, the full-wave rectifier circuit 20 and the first capacitor C1 are associated with each of the power generation elements. A charge control circuit 30 may be provided.

  10 ... Power supply circuit, 11a, 11b ... Input terminal, 12a, 12b ... Output terminal, 13 ... Control signal input terminal, 20 ... Full-wave rectifier circuit, 30 ... Charge control circuit, 40 ... Output control circuit, TR1 to TR7 ... Transistor , TR8 ... FET, IC1 ... Linear regulator, D1-D5 ... Diode, ZD1-ZD5 ... Zener diode, R1-R17 ... Resistor, Cp ... Capacitor, C1 ... First capacitor, C2 ... Second capacitor, C3, C4 ... Capacitor.

Claims (4)

A power supply circuit that stores minute generated power generated by a power generation element and supplies the stored power to a load,
Power storage means for storing a first capacitor having a predetermined first capacitance having a low potential side terminal and a high potential side terminal, and storing the generated power in the first capacitor;
A second capacitor having a low potential side terminal and a high potential side terminal and having a second capacitance larger than the first capacitance;
The low-potential side terminal of the first capacitor is connected to the low-potential side terminal of the second capacitor, and the conductive state is established when the inter-terminal voltage of the first capacitor reaches a predetermined first threshold voltage. From the high potential side terminal of the first capacitor to the high potential side terminal of the second capacitor until the inter-terminal voltage of the first capacitor becomes a second threshold voltage lower than the first threshold voltage. Electric power is supplied and stored in the second capacitor, and when the voltage between the terminals of the first capacitor reaches the second threshold voltage, the high voltage of the second capacitor is increased from the high potential side terminal of the first capacitor. Charging control means for stopping power supply to the potential side terminal;
When the inter-terminal voltage of the second capacitor reaches a third threshold voltage lower than the predetermined second threshold voltage, the conductive state is established and the inter-terminal voltage of the second capacitor becomes the third threshold voltage. Electric power is supplied from the second capacitor to the load until a fourth threshold voltage lower than the voltage is reached, and the second capacitor voltage when the terminal voltage of the second capacitor reaches the fourth threshold voltage. An output control means for stopping power supply from the capacitor to the load. The power output from the power generation element is power by alternating current,
The first power storage means includes a rectifier circuit that rectifies input generated power,
The power supply circuit according to claim 1, wherein the first capacitor is connected in parallel to an output terminal of the rectifier circuit. The output means includes means for cutting off power supply from the second capacitor to the load based on a control signal input from the outside via a control signal input terminal. The power supply circuit described. Comprising two or more sets of the first power storage means and the second power storage means;
The power supply circuit according to claim 1, wherein one second capacitor is charged from the two or more sets of the first power storage unit and the second power storage unit.

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