Overshoot prevention for deep dimming startup

Patent metadata

Field	Value
Publication number	US-9608527-B1
Application number	US-201514621310-A
Country	US
Kind code	B1
Filing date	Feb 12, 2015
Priority date	Feb 13, 2014
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

An apparatus includes an energy storage device, a driver circuit configured to receive energy from the energy storage device, and a bleed circuit configured to reduce an amount of the energy received by the driver circuit from the energy storage device. The bleed circuit is configured to reduce the amount of the energy received by the driver circuit during a startup period. The energy storage device may include a transformer, the driver circuit and bleed circuit being coupled to first and second windings of the transformer, respectively. A method includes receiving, by a driver circuit, energy from an energy storage device, and reducing, using a bleed circuit, the energy received by the driver circuit during a startup period. The energy storage device may include a transformer, the driver circuit and bleed circuit being coupled to first and second windings of the transformer, respectively.

First claim

What is claimed is:

1. An apparatus comprising:
an energy storage device;
a driver circuit configured to receive energy from the energy storage device; and
a bleed circuit configured to reduce an amount of the energy received by the driver circuit from the energy storage device,
wherein the driver circuit is configured to receive the energy from the storage device during a discharge interval, and
wherein the bleed circuit is configured to reduce the amount of the energy received by the driver circuit during the discharge interval.

2. The apparatus of claim 1 , wherein the bleed circuit is configured to reduce the amount of the energy received by the driver circuit during a startup period.

3. The apparatus of claim 1 , wherein the apparatus is configured to store the energy into the energy storage device during a charge interval, and
wherein the charge interval is disjoint from the discharge interval.

4. The apparatus of claim 3 , wherein the apparatus is configured to receive a control signal and control a magnitude of the energy stored into the energy storage device according to the control signal.

5. The apparatus of claim 1 , wherein the bleed circuit is configured to begin reducing the amount of the energy received by the driver circuit at a bleed start time determined according to a delay time from an end of the charge interval, a voltage produced by the energy stored in the energy storage device, or both.

6. The apparatus of claim 1 , wherein the bleed circuit is configured to stop reducing the amount of the energy received by the driver circuit at a bleed stop time determined according to one or more of a duration from an end of the charge interval, a time from a bleed start time, and a voltage produced by the energy stored in the energy storage device.

7. The apparatus of claim 1 , wherein the energy storage device includes a transformer,
wherein the driver circuit is coupled to a primary winding of the transformer, and
wherein the bleed circuit is coupled to an auxiliary winding of the transformer.

8. The apparatus of claim 7 , wherein the bleed circuit is configured to reduce the amount of the energy received by the driver circuit by controlling a current of the auxiliary winding.

9. The apparatus of claim 7 , further comprising a voltage supply circuit configured to provide a supply voltage and coupled to the auxiliary winding.

10. The apparatus of claim 1 , wherein the apparatus is a dimming system.

11. The apparatus of claim 1 , wherein the apparatus is provided in an integrated circuit.

12. A method comprising:
receiving, by a driver circuit, energy from an energy storage device;
reducing, using a bleed circuit, the energy received by the driver circuit during a startup period;
storing the energy into the energy storage device during a plurality of charge intervals;
receiving the energy from the energy storage device during a plurality of discharge intervals interleaved with the plurality of charge intervals; and
reducing the energy received by the driver circuit during the plurality of discharge intervals during the startup period.

13. The method of claim 12 , wherein the energy storage device is a transformer, wherein the driver circuit is coupled to a first winding of the transformer, and wherein the bleed circuit is coupled to a second winding of the transformer.

14. The method of claim 13 , wherein reducing the energy received by the driver circuit includes controlling a current of the second winding of the transformer.

15. The method of claim 12 , further comprising:
starting the reduction of the energy received by the driver circuit according to a delay time after a charge interval, a voltage of the energy storage device, or both.

16. The method of claim 15 , further comprising:
stopping the reduction of the energy received by the driver circuit according to one or more of a duration from an end of the charge interval, a time of starting the reduction of the energy received by the driver circuit, and the voltage produced by the energy stored in the energy storage device.

17. The method of claim 12 , further comprising:
receiving a control signal; and
controlling a magnitude of the energy stored in the energy storage device according to the control signal.

Assignees

• Marvell Int Ltd

Inventors

• Choi Jinho
• Peng Hao
• Shu Biing Long
• Zhang Wanfeng

Classifications

• H02M3/33507 Primary

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M1/0006

  Arrangements for supplying an adequate voltage to the control circuit of converters · CPC title

• H02M1/36

  Means for starting or stopping converters · CPC title