Electronic device

Patent metadata

Field	Value
Publication number	US-10938205-B2
Application number	US-201716334182-A
Country	US
Kind code	B2
Filing date	Sep 21, 2017
Priority date	Sep 26, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

An electronic device according to the present invention includes a power supply unit and a load, the power supply unit including a ground terminal, a rectifier circuit, a circuit section connected to a DC output of the rectifier circuit, the circuit section supplying electric power to the load, a first varistor connected at one end thereof to one input end of the rectifier circuit, a second varistor connected at one end thereof to another input end of the rectifier circuit and connected at another end thereof to another end of the first varistor and an arrester connected at one end thereof to the another end of the second varistor and connected at another end thereof to the ground terminal, wherein an electrostatic capacity of each of the first and second varistors is 40% or more of a sum of earth capacitances of the power supply unit and the load.

First claim

The invention claimed is:

1. An electronic device, comprising:
a power supply unit; and
a load,
the power supply unit including:
an input section receiving electric power from an alternating current power supply;
a ground terminal;
a rectifier circuit connected to the input section;
a circuit section connected to a DC output of the rectifier circuit, the circuit section supplying electric power to the load;
a first varistor connected at one end thereof to one input end of the rectifier circuit between the input section and the rectifier circuit;
a second varistor connected at one end thereof to another input end of the rectifier circuit and connected at another end thereof to another end of the first varistor between the input section and the rectifier circuit; and
a suppression element connected at one end thereof to the another end of the second varistor and connected at another end thereof to the ground terminal,
wherein an electrostatic capacity of each of the first and second varistors is 40% or more of a sum of earth capacitances of the power supply unit and the load.

2. The electronic device according to claim 1 , wherein the electrostatic capacity of each of the first and second varistors is 200 pF or more.

3. The electronic device according to claim 1 , wherein the circuit section comprises a switch device and a diode, and
the sum of earth capacitances is a sum of earth capacitances of the switch device, the diode, and the load.

4. The electronic device according to claim 1 , further comprising a noise filter circuit connected between the first and second varistors and the input section.

5. The electronic device according to claim 4 , wherein the noise filter circuit comprises a coil.

6. The electronic device according to claim 1 , further comprising a noise filter circuit connected between the first and second varistors and the rectifier circuit.

7. The electronic device according to claim 1 , wherein the suppression element includes a capacitive element.

8. The electronic device according to claim 7 , wherein the capacitive element is a first capacitor.

9. The electronic device according to claim 7 , wherein an electrostatic capacity of the capacitive element is equal to or larger than the electrostatic capacity of each of the first and second varistors.

10. The electronic device according to claim 7 , further comprising an arrester connected in parallel to the capacitive element.

11. The electronic device according to claim 1 , wherein the load is a light source, and
the electronic device is an illumination device.

12. The electronic device according to claim 1 , wherein the suppression element comprises an arrester.

13. The electronic device according to claim 12 , wherein the suppression element comprises a capacitor.

14. The electronic device according to claim 1 , wherein the suppression element is configured to suppress noise associated with non-DC circuit components.

15. The electronic device according to claim 1 , wherein the suppression element is configured to suppress voltage associated with surge.

16. The electronic device according to claim 1 , wherein the suppression element is configured to suppress (1) noise associated with non-DC circuit components and (2) voltage associated with surge.

Assignees

• Mitsubishi Electric Corp
• Mitsubishi Electric Lighting Corp

Inventors

• Ohtsu Teiji
• Kamikura Mamoru
• Yamagami Akira
• Funayama Shinsuke

Classifications

• H02H9/06 Primary

  using spark-gap arresters · CPC title

• H05B47/10 Primary

  Controlling the light source · CPC title

• H02H9/04

  responsive to excess voltage (lightning arrestors H01C7/12, H01C8/04, H01G9/18, H01T) · CPC title

• H02M7/062

  Avoiding or suppressing excessive transient voltages or currents · CPC title

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title