SWITCHING POWER CIRCUIT, AND LIGHTING DEVICE FOR SEMICONDUCTOR LIGHT-EMITTING ELEMENT AND ILLUMINATION APPARATUS USING SAME

• US 20120194090A1
• Filed: 01/27/2012
• Published: 08/02/2012
• Est. Priority Date: 01/28/2011
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: ESAKI, Sana, HIRAMATU, Akinori
• Granted Patent: US 8,564,213 B2
• Time in Patent Office: Days
• US Class Current: 315/200.R
• CPC Class Codes: H02H 9/002 limiting inrush current on switching on of inductive loads subjected to remanence, e.g. transformers
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 7/2176 comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output
• CPC Class Codes: H03K 19/00346 Modifications for eliminating interference or parasitic voltages or currents
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology

Abstract

A switching power circuit includes a first switching element having one end connected to a positive electrode of a first capacitor, a second switching element having one end connected to a negative electrode of the first capacitor, an inductive element having one end connected to the other ends of the first and the second switching element, a semiconductor switching element connected in parallel to the current limiting resistor, and a second capacitor connected to a control electrode of the semiconductor switching element. The second capacitor is charged by using a voltage induced to the inductive element when the first or the second switching element is off.

Claims

1. A switching power circuit comprising:

a rectifying circuit for rectifying AC power;

a first capacitor connected to an output terminal of the rectifying circuit through a current limiting resistor for restraining an inrush current, the first capacitor being a smoothing capacitor;

a first switching element having one end connected to a positive electrode of the first capacitor;

a second switching element having one end connected to a negative electrode of the first capacitor;

an inductive element having one end connected to the other ends of the first and the second switching element;

a semiconductor switching element connected in parallel to the current limiting resistor; and

a second capacitor connected to a control electrode of the semiconductor switching element,

wherein the second capacitor is charged by using a voltage induced to the inductive element when the first or the second switching element is off.

2. The switching power circuit of claim 1, wherein a negative electrode of the second capacitor is connected to the positive electrode of the first capacitor,

wherein the switching power circuit further comprises:

a third capacitor having a negative electrode connected to said one end of the inductive element; and

a current path for transmitting charges toward a positive electrode of the second capacitor from a positive electrode of the third capacitor when the first switching element is on.

3. The switching power circuit of claim 2, wherein the third capacitor is charged from an intermediate tab of the inductive element or charged by a voltage applied between two ends of the first switching element when the second switching element is on.

4. The switching power circuit of claim 2, wherein the first switching element has a control electrode,

wherein the switching power circuit further comprises a control circuit for providing a control signal to the control electrode, and

wherein the third capacitor provides a control power voltage to the control circuit.

5. The switching power circuit of claim 2, wherein the second switching element has a control electrode,

wherein the switching power circuit further comprises at the negative electrode side of the first capacitor:

a control circuit for providing a control signal to the control electrode; and

a control power circuit for providing a control power voltage to the control circuit,

wherein the switching power circuit further comprises a current path for allowing a charge current to flow to the positive electrode of the third capacitor from a positive electrode of the control power circuit when the second switching element is on.

6. The switching power circuit of claim 1, wherein one of the first and the second switching element has a control electrode, and the other is a diode reversely biased by the first capacitor.

7. A lighting device for lighting a semiconductor light-emitting element comprising:

the switching power circuit of claim 1.

8. An illumination apparatus comprising:

the lighting device of claim 7; and

the semiconductor light-emitting element connected between the other end of the inductive element and the positive electrode or the negative electrode of the first capacitor.