Start-up voltage for solid-state lighting controller

• US 9,179,523 B1
• Filed: 09/04/2014
• Issued: 11/03/2015
• Est. Priority Date: 09/09/2013
• Status: Expired due to Fees

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Choi, Jinho, Zhang, Wanfeng, Ryu, Young Chul, Qian, Chang
• Primary Examiner(s): A, Minh D
• Assistant Examiner(s): Alaeddini, Borna
• Application Number:
  US14/476,992
• Time in Patent Office: 425 Days
• Field of Search: 315/193, 315/197, 315/201, 315/247
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/382 with galvanic isolation between input and output
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A controller, which may be a controller for solid-state lighting, includes a transformer, and a control circuit having a bias voltage input. The control circuit activates when voltage applied to the bias voltage input reaches a threshold. The transformer has a feedback output to the bias voltage input. The controller also has a bias voltage circuit including a resonant circuit providing a resonant current, and a bias capacitor charged by the resonant current, applying start-up bias voltage to the bias voltage input. The controller further has a cutoff to shut down the resonant current when the transformer feedback output is above the threshold. A method of operating the a controller includes providing a resonant current to charge a start-up bias capacitor. The method also includes automatically cutting off the resonant current when the transformer feedback output is above the threshold. This may be determined by monitoring the bias voltage input.

Claims

1. A controller, comprising:

a transformer;

a control circuit having a bias voltage input, the control circuit activating when voltage applied to the bias voltage input reaches a threshold, the transformer having feedback output to the bias voltage input;

a bias voltage circuit applying start-up bias voltage to the bias voltage input, the bias voltage circuit having;

a resonant circuit providing a resonant current,

a bias capacitor charged by the resonant current, wherein voltage on the bias capacitor is the start-up bias voltage applied to the bias voltage input, and

a cutoff, comprising at least one diode, to shut down the resonant current when the transformer feedback output is above the threshold;

wherein;

the resonant circuit includes a voltage divider that divides a supply voltage to produce a divided voltage for the resonant current; and

the voltage divider is adjusted so that when the transformer feedback output is above the threshold, voltage on the transformer feedback output is above the divided voltage, thereby turning off the at least one diode.

2. The controller of claim 1 wherein the voltage divider includes a first voltage divider capacitor in series with a second voltage divider capacitor.

3. The controller of claim 2 wherein:

the voltage divider further includes a first voltage divider resistor in series with a second voltage divider resistor; and

the first and second voltage divider resistors are in parallel with the first and second voltage divider capacitors.

4. The controller of claim 1 wherein the at least one diode comprises a first diode between the voltage divider and the bias capacitor, the first diode having its forward direction from the voltage divider toward the bias capacitor.

5. The controller of claim 4 wherein the at least one diode further comprises a second diode between the transformer feedback output and the bias voltage input, the second diode having its forward direction from the transformer feedback output toward the bias voltage input.

6. The controller of claim 1 further comprising:

a dimmer circuit;

wherein;

when the transformer feedback output is above the threshold, and the cutoff shuts down the resonant current in the resonant circuit, the resonant circuit functions as a damping circuit to dampen interference from the dimming circuit.

7. The controller of claim 6 wherein the dimmer circuit comprises a triac.

8. The controller of claim 6 wherein the dimmer circuit comprises a thyristor.

9. The controller of claim 1 further comprising:

a supply of alternating current; and

a rectifier that rectifies the alternating current and supplies rectified current to the resonant circuit.

10. The controller of claim 9 wherein the rectifier comprises a diode bridge.

11. The controller of claim 1 wherein the controller is a controller for solid-state lighting.

12. A method of operating a controller, the controller including a transformer, and a control circuit having a bias voltage input, the control circuit activating when voltage applied to the bias voltage input reaches a threshold, the transformer having feedback output to the bias voltage input;

the method comprising;

applying start-up bias voltage to the bias voltage input, by providing a resonant current to charge a start-up bias capacitor, wherein voltage on the start-up bias capacitor is applied to the bias voltage input as the start-up bias voltage; and

automatically cutting off the resonant current, using at least one diode, when the transformer feedback output is above the threshold;

wherein;

the providing the resonant current includes a dividing a supply voltage to produce a divided voltage for the resonant current; and

the dividing the supply voltage is adjusted so that when the transformer feedback output is above the threshold, voltage on the transformer feedback output is above the divided voltage, thereby turning off the at least one diode.

13. The method of claim 12, wherein:

the applying is performed using a resonant circuit; and

when the transformer feedback output is above the threshold, and the resonant current is shut off, the resonant circuit is used as a damping circuit.

14. The method of claim 12 wherein the method is for controlling solid-state lighting.

15. A method of operating a solid-state lighting controller, the solid-state lighting controller including a transformer, and a control circuit having a bias voltage input, the transformer having feedback output to the bias voltage input;

the method comprising;

applying start-up bias voltage to the bias voltage input, by providing a start-up current to charge a start-up bias capacitor, wherein voltage on the start-up bias capacitor is applied to the bias voltage input as the start-up bias voltage;

monitoring, by the solid state lighting controller, voltage at the bias voltage input;

activating, by the solid state lighting controller, of a driving signal when the voltage at the bias voltage input reaches a threshold, whereby current flows in the transformer, including in the transformer feedback output, to charge an operating mode bias capacitor, thereby generating an operating mode bias voltage; and

discontinuing the start-up current, using at least one diode, when the operating mode bias voltage reaches the threshold;

wherein;

the providing the start-up current includes a dividing a supply voltage to produce a divided voltage for the start-up current; and

the dividing the supply voltage is adjusted so that when the transformer feedback output is above the threshold, voltage on the transformer feedback output is above the divided voltage, thereby turning off the at least one diode.

16. The method of claim 15, wherein:

the applying is performed using a resonant circuit; and

after the discontinuing, the resonant circuit is used as a damping circuit.

17. The method of claim 16 wherein the applying comprises providing a rectified alternating current.