ELECTRONIC BALLAST FOR LIGHTING UNIT AND LIGHTING APPARATUS

• US 20130169185A1
• Filed: 08/25/2011
• Published: 07/04/2013
• Est. Priority Date: 09/10/2010
• Status: Active Grant

• Current Assignee: OSRAM GmbH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Dai, Hong, Guo, Yuancheng, Gao, Wei, Ma, Changsong
• Granted Patent: US 8,917,030 B2
• Time in Patent Office: Days
• US Class Current: 315/247
• CPC Class Codes: H05B 41/2825 by means of a bridge converter in the final stage H05B41/285 takes precedence
• CPC Class Codes: H05B 41/36 Controlling
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

An electronic ballast for a lighting unit may include: a Power Factor Correction (PFC) circuit, an inverter, and a control circuit for controlling startup of the inverter, wherein the control circuit is coupled between the PFC circuit and the inverter and includes: a switching device coupled in a startup loop for the inverter; a unidirectional conductive device coupled between a PFC power supply circuit for providing an operation current to a PFC controller of the PFC circuit and an input of the PFC controller, for preventing a startup current flowing through the PFC circuit from triggering the switching device; and a triggering device coupled to the switching device and a connection point between the unidirectional conductive device and the PFC power supply circuit, for controlling switch-on and -off of the switching device.

Claims

1. An electronic ballast for a lighting unit, comprising:

a Power Factor Correction (PFC) circuit,

an inverter, and

a control circuit for controlling startup of the inverter,

wherein the control circuit is coupled between the PFC circuit and the inverter and comprises;

a switching device coupled in a startup loop for the inverter;

a unidirectional conductive device coupled between a PFC power supply circuit for providing an operation current to a PFC controller of the PFC circuit and an input of the PFC controller, for preventing a startup current flowing through the PFC circuit from triggering the switching device; and

a triggering device coupled to the switching device and a connection point between the unidirectional conductive device and the PFC power supply circuit, for controlling switch-on and -off of the switching device.

2. The electronic ballast according to claim 1,

wherein the switching device is further coupled in an oscillation loop for the inverter.

3. The electronic ballast according to claim 2, further comprising:

first and second reservoir capacitors coupled between the PFC circuit and the inverter,

wherein the second reservoir capacitor functions as a voltage source of the startup loop and the oscillation loop for the inverter.

4. The electronic ballast according to claim 1,

wherein the PFC power supply circuit comprises a secondary winding of a boost transformer, a capacitor, a resistor, a diode and a voltage stabilizing diode.

5. The electronic ballast according to claim 1,

wherein the inverter is configured as a half-bridge form including first and second inverter switches, and a startup capacitor in the startup loop is charged by a startup current flowing through the startup loop for the inverter, so as to provide a startup voltage for initially activating the second inverter switch.

6. The electronic ballast according to claim 1,

wherein the switching device comprises any one of a triac, a bipolar transistor and a field effect transistor.

7. The electronic ballast according to claim 1,

wherein the triggering device comprises a voltage stabilizing diode and a resistor which are connected in series or a capacitor.

8. The electronic ballast according to claim 1,

wherein the unidirectional conductive device comprises a diode or a thyristor.

9. A lighting apparatus, comprising:

an electronic ballast, comprising;

a Power Factor Correction (PFC) circuit,

an inverter, and

a control circuit for controlling startup of the inverter,

wherein the control circuit is coupled between the PFC circuit and the inverter and comprises;

a switching device coupled in a startup loop for the inverter;

a unidirectional conductive device coupled between a PFC power supply circuit for providing an operation current to a PFC controller of the PFC circuit and an input of the PFC controller, for preventing a startup current flowing through the PFC circuit from triggering the switching device; and

a triggering device coupled to the switching device and a connection point between the unidirectional conductive device and the PFC power supply circuit, for controlling switch-on and -off of the switching device;

a lighting unit which is driven by the electronic ballast to operate.

10. The lighting apparatus according to claim 9,

wherein the lighting unit is a gas discharge lamp.