Piezoelectric power generation module and remote controller

Patent metadata

Field	Value
Publication number	US-10014801-B2
Application number	US-201615202946-A
Country	US
Kind code	B2
Filing date	Jul 6, 2016
Priority date	Jan 22, 2014
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A rectifier circuit rectifies power generation voltage of a piezoelectric element to generate DC voltage and supplies the power generation voltage to a load. Upon termination of a process started upon reception of the DC voltage supplied from the rectifier circuit, the load sets a discharge switch to a conduction state using an output port signal. The electric charge remaining in the piezoelectric element is reset to zero by the discharge switch.

First claim

The invention claimed is:

1. A power generation device comprising:
a piezoelectric element;
a discharge mechanism connected in parallel to the piezoelectric element;
a rectifier circuit including input terminals connected to the piezoelectric element and output terminals that output a direct-current voltage;
a switch control circuit including first and second input terminals respectively connected to the output terminals of the rectifier circuit, and an output terminal that outputs a switch control signal;
a capacitive element connected in parallel to the first and second input terminals of the switch control circuit; and
a switch that is connected to the output terminal of the rectifier circuit and that switches between a conductive state and an off state based on the switch control signal,
wherein a control signal sets the discharge mechanism to a conductive state after the switch is set to the conductive state.

2. The power generation device according to claim 1 , further comprising:
a load coupled to the output terminals of the rectifier circuit when the switch is in the conductive state,
wherein the load is configured to generate the control signal to set the discharge mechanism to the conductive state after the load performs an operation.

3. The power generation device according to claim 1 , wherein an electrostatic capacity of the piezoelectric element is greater than or equal to an electrostatic capacity of the capacitive element.

4. The power generation device according to claim 1 , wherein the discharge mechanism is an electronic switch.

5. The power generation device according to claim 1 , wherein the discharge mechanism switches between the conductive state and an off state based on the control signal that is generated by a load.

6. The power generation device according to claim 1 , further comprising:
a control circuit coupled between the output terminal of the switch control circuit and the discharge mechanism and configured to generate the control signal,
wherein the discharge mechanism switches between the conductive state and an off state based on the control signal generated by the control circuit in response to the conductive state of the first switch.

7. The power generation device according to claim 1 , wherein the piezoelectric element is configured to generate a voltage that is supplied to the rectifier circuit when pressure is applied to or released from the piezoelectric element.

8. The power generation device according to claim 7 , wherein the piezoelectric element comprises a piezoelectric body, a metal plate and a pair of electrodes disposed on opposing sides of the piezoelectric body.

9. The power generation device according to claim 7 , wherein the switch control circuit compares a rectified voltage output by the rectifier circuit with a threshold voltage and controls the switch to the conductive state, via the switch control signal, when the rectified voltage is greater than the threshold voltage.

10. The power generation device according to claim 9 , wherein, when the switch is in the conductive state, the switch control circuit compares a rectified voltage output by the rectifier circuit with an additional threshold voltage lower than the threshold voltage and controls the switch to the off state, via the switch control signal, when the rectified voltage is equal to or less than the additional threshold voltage.

11. The power generation device according to claim 9 , wherein the switch control circuit comprises:
first, second and third resistors connected in series between the first and second input terminals;
an additional switch coupled to the first input terminal and a node between the first and second resistors; and
a comparator have a non-inverting input coupled to a node between the second and third resistors, an inverting input coupled to the voltage threshold, and an output coupled to the output terminal of the switch control circuit.

12. The power generation device according to claim 11 , wherein the output of the comparator is further coupled to the additional switch to control a state of the additional switch between a conductive state and an off state.

13. A remote controller comprising:
the piezoelectric power generation device according to claim 1 ; and
a radio-frequency circuit configured to perform a process upon supply of the direct-current voltage from the switch to the radio-frequency circuit, and
wherein, after the process is complete, the radio-frequency circuit generates the control signal that sets the discharge mechanism to the conductive state.

14. A power generation module comprising:
a piezoelectric element;
a discharge mechanism connected in parallel to the piezoelectric element;
a rectifier circuit including input terminals connected to the piezoelectric element and output terminals that output a direct-current voltage;
a switch control circuit including first and second input terminals respectively connected to the output terminals of the rectifier circuit, and an output terminal that outputs a switch control signal;
a capacitive element connected in parallel to the first and second input terminals of the switch control circuit;
a switch that is connected to the output terminal of the rectifier circuit and that switches between a conductive state and an off state based on the switch control signal; and
a load coupled to the output terminals of the rectifier circuit when the switch is in the conductive state, the load being configured to generate a control signal to set the discharge mechanism to a conductive state after the switch is set to the conductive state.

15. The power generation module according to claim 14 , wherein the load is configured to perform a process upon supply of the direct-current voltage from the switch, and, after the process is complete, generate the control signal to set the discharge mechanism to the conductive state.

16. The power generation module according to claim 15 , wherein the discharge mechanism switches between the conductive state and an off state based on the control signal that is generated by the load.

17. The power generation module according to claim 14 , wherein the piezoelectric element is configured to generate a voltage that is supplied to the rectifier circuit when pressure is applied to or released from the piezoelectric element.

18. The power generation module according to claim 17 , wherein the switch control circuit compares a rectified voltage output by the rectifier circuit with a threshold voltage and controls the switch to the conductive state, via the switch control signal, when the rectified voltage is greater than the threshold voltage.

19. The power generation module according to claim 18 , wherein, when the switch is in the conductive state, the switch control circuit compares a rectified voltage output by the rectifier circuit with an additional threshold voltage lower than the threshold voltage and controls the switch to the off state, via the switch control signal, when the rectified voltage is equal to or less than the additional threshold voltage.

20. The power generation module according to claim 19 , wherein the switch control circuit comprises:
first, second and third resistors connected in series between the first and second input terminals;
an additional switch coupled to the first input terminal and a node between the first and second resistors; and
a comparator have a non-inverting input coupled to a node between the second and third resistors, an inverti

Assignees

• Murata Manufacturing Co

Inventors

• Horiguchi Chikahiro
• Takahashi Kohei

Classifications

• G08C2201/112

  Mechanical energy, e.g. vibration, piezoelectric · CPC title

• G08C17/02

  using a radio link · CPC title

• H02N2/181 Primary

  Circuits; Control arrangements or methods · CPC title

• H01L41/1136

  Electricity · mapped topic

• H01L41/1134

  Electricity · mapped topic