Multi-mode dimming control method and dimming circuit

Patent metadata

Field	Value
Publication number	US-10638580-B2
Application number	US-201916391372-A
Country	US
Kind code	B2
Filing date	Apr 23, 2019
Priority date	Jun 20, 2018
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

The present disclosure provides a multi-mode dimming control method and a dimming circuit. The multi-mode current control method includes: receiving a dimming signal, and controlling the dimming circuit to be operated in a plurality of modes in an arbitrary order according to the dimming signal, wherein the plurality of modes include any two or all of a first dimming mode, a second dimming mode, and a third dimming mode. Also, the dimming circuit can be operated in different combinations of different modes according to actual needs, so that the requirements of a wide dimming range and a low output current ripple can be realized.

First claim

What is claimed is:

1. A dimming circuit, comprising:
a power conversion unit comprising at least one main switch;
a dimming signal processor, configured to receive a dimming signal, and generate a control signal according to the dimming signal;
a dimming controller electrically connected to the dimming signal processor, and configured to generate a driving signal according to the control signal, and output the driving signal to the main switch;
wherein the dimming controller controls the power conversion unit to be operated in a plurality of modes in an arbitrary order, the plurality of modes comprise any two or all of a first dimming mode, a second dimming mode, and a third dimming mode,
in the first dimming mode, the dimming signal processor is configured to generate a first control signal according to the dimming signal, and the dimming controller is configured to generate a first peak current reference according to the first control signal to control an output current of the dimming circuit;
in the second dimming mode, the dimming signal processor is configured to generate a second control signal according to the dimming signal, and the dimming controller is configured to set a second peak current reference, and control a turn-off time of the main switch according to the second peak current reference and the second control signal, to control the output current of the dimming circuit; and
in the third dimming mode, the dimming signal processor is configured to generate a third control signal according to the dimming signal, the dimming controller is configured to set a third peak current reference, and chop the third peak current reference according to the third control signal to control the output current of the dimming circuit.

2. The dimming circuit according to claim 1 , wherein the dimming controller comprises:
a control chip including a reference-signal input terminal, a driving-signal output terminal, a sampling signal terminal and a ZCD detection terminal.

3. The dimming circuit according to claim 2 , wherein the dimming controller further comprises:
a first dimming unit electrically connected to the reference-signal input terminal of the control chip, and configured to receive the first control signal and output the first peak current reference to the reference-signal input terminal.

4. The dimming circuit according to claim 2 , wherein the dimming controller further comprises:
a second dimming unit electrically connected to the ZCD detection terminal of the control chip, and configured to receive the second control signal to turn on the main switch.

5. The dimming circuit according to claim 2 , wherein the dimming controller further comprises:
a third dimming unit electrically connected to the reference-signal input terminal of the control chip, and configured to receive the third control signal to chop the third peak current reference.

6. The dimming circuit according to claim 5 , wherein in the first dimming mode, the first control signal is a PWM signal, and the second control signal enables ZCD detection, and the third control signal turns off a controlled switch in the third dimming unit.

7. The dimming circuit according to claim 5 , wherein in the second dimming mode, the second peak current reference is a minimum value of the first peak current reference, and the third control signal turns off a controlled switch in the third dimming unit.

8. The dimming circuit according to claim 5 , wherein the third dimming unit is electrically connected to the first diming unit, and in the third dimming mode, the third peak current reference is a minimum of the first peak current reference, and the second control signal is a low level voltage.

9. The dimming circuit according to claim 8 , wherein the dimming controller comprises:
a fourth dimming unit electrically connected between the reference-signal input terminal of the control chip and the third dimming unit, and configured to receive a fourth control signal to further chop the chopped third peak current reference.

10. The dimming circuit according to claim 9 , wherein the fourth dimming unit includes a controlled switch.

11. A multi-mode dimming control method for a dimming circuit, the dimming circuit comprising at least one main switch, the method comprising:
receiving a dimming signal;
controlling the dimming circuit to be operated in a plurality of modes in an arbitrary order according to the dimming signal, the plurality of modes comprising any two or all of a first dimming mode, a second dimming mode, and a third dimming mode; wherein,
in the first dimming mode, generating a first control signal according to the dimming signal, generating a first peak current reference according to the first control signal, and controlling an output current of the dimming circuit according to the first peak current reference;
in the second dimming mode, generating a second control signal according to the dimming signal, setting a second peak current reference, and controlling a turn off time of the main switch comprised in the dimming circuit according to the second peak current reference and the second control signal, to control the output current of the dimming circuit; and
in the third dimming mode, generating a third control signal according to the dimming signal, setting a third peak current reference, and chopping the third peak current reference according to the third control signal to control the output current of the dimming circuit.

12. The multi-mode current control method according to claim 11 , further comprising:
controlling the dimming circuit to be operated in a fourth dimming mode according to the dimming signal; and
in the fourth dimming mode, generating a fourth control signal according to the dimming signal, and further chopping the chopped third peak current reference according to the fourth control signal to further control the output current of the dimming circuit.

13. The multi-mode current control method according to claim 12 , wherein the first control signal, the second control signal, the third control signal, and the fourth control signal are PWM signals.

14. The multi-mode current control method according to claim 11 , wherein the second peak current reference is a minimum value of the first peak current reference.

15. The multi-mode current control method according to claim 11 , wherein the third peak current reference is a minimum value of the first peak current reference.

Assignees

• Delta Electronics Inc

Inventors

• Wu Que
• Fu Xiaoping
• Zheng Kaibin
• Zhang Xinghua

Classifications

• H05B45/37 Primary

  Converter circuits · CPC title

• H05B45/10

  Controlling the intensity of the light · CPC title

• H05B45/14 Primary

  using electrical feedback from LEDs or from LED modules · CPC title