Controller, light source driving circuit and method for controlling light source module

• US 10,537,000 B2
• Filed: 04/03/2019
• Issued: 01/14/2020
• Est. Priority Date: 04/18/2018
• Status: Active Grant

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Ren, Zhimou, Li, Yanjun, Li, Binqiang, Hu, Zhenqiu
• Primary Examiner(s): Tran, Thuy V
• Application Number:
  US16/374,435
• Publication Number:
  US 20190327805A1
• Time in Patent Office: 286 Days
• Field of Search: 315291, 315308
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/30 Driver circuits
• CPC Class Codes: H05B 47/16 by timing means

Abstract

A controller includes a current input terminal, a switch monitoring terminal, a first control terminal, a second control terminal and a current monitoring terminal. The current input terminal is coupled to a power source through a rectifier and receives electric power from the power source. The switch monitoring terminal is coupled to a power switch and receives a switch monitoring signal indicating the on/off state of the power switch. The power switch is coupled between the rectifier and the power source. Based on the switch monitoring signal, the first control terminal turns on or turns off a first light source in a light source module and the second control terminal turns on or turns off a second light source in the light source module. The current monitoring terminal monitors a current flowing through the first light source and a current flowing through the second light source.

Claims

1. A controller operable for controlling a light source module, said controller comprising:

a current input terminal, coupled to a power source through a rectifier, operable for receiving electric power from said power source;

a switch monitoring terminal, coupled to a power switch, operable for receiving a switch monitoring signal indicating the on/off state of said power switch, wherein said power switch is coupled between said rectifier and said power source;

a first control terminal, operable for turning on a first light source in said light source module and operable for turning off said first light source, based on said switch monitoring signal;

a second control terminal, operable for turning on a second light source in said light source module and operable for turning off said second light source, based on said switch monitoring signal; and

a current monitoring terminal, operable for monitoring a current flowing through said first light source and a current flowing through said second light source.

2. The controller of claim 1, wherein said controller further comprises:

a first switch coupled to said first control terminal;

a second switch coupled to said second control terminal;

a third switch coupled to said current input terminal; and

a logic control module, coupled to said first switch, said second switch and said third switch, wherein said logic control module is operable for;

regulating a total current of said light source module by controlling said third switch, turning on said first light source by controlling said first switch and turning off said first light source by controlling said first switch, and turning on said second light source by controlling said second switch and turning off said second light source by controlling said second switch.

3. The controller of claim 2, wherein a current flows from said current input terminal through said third switch, said current monitoring terminal and an inductor to ground when said third switch is on.

4. The controller of claim 3, wherein a current flows through said inductor, said first light source, said first control terminal, said first switch and said current monitoring terminal when said third switch is off and said first switch is on;

and wherein a current flows through said inductor, said second light source, said second control terminal, said second switch and said current monitoring terminal when said third switch is off and said second switch is on.

5. The controller of claim 2, wherein said logic control module comprises a memory module, wherein said logic control module is operable for generating a first control signal, said first control signal for turning on said first light source and for turning off said first light source, based on data stored in said memory module;

wherein said logic control module is further operable for generating a second control signal, said second control signal for turning on said second light source and for turning off said second light source, based on said data stored in said memory module.

6. The controller of claim 5, wherein said memory module comprises:

a first metal-oxide semiconductor capacitor (MOS capacitor);

a second MOS capacitor; and

a metal-oxide semiconductor field effect transistor (MOSFET),

wherein the gate of said first MOS capacitor, the gate of said second MOS capacitor and the gate of said MOSFET are connected together;

wherein the area of said first MOS capacitor is greater than the area of said second MOS capacitor;

wherein the substrate, the source and the drain of said first MOS capacitor are connected together; and

wherein the substrate, the source and the drain of said second MOS capacitor are connected together.

7. The controller of claim 5, wherein said logic control module further comprises:

a trigger monitoring unit, operable for generating a trigger signal based on said switch monitoring signal;

a logic unit, operable for generating a read enable signal and a write enable signal based on said switch monitoring signal, and also operable for generating a regulating signal based on said trigger signal; and

a reading and writing unit, operable for writing to said memory module based on said write enable signal and said regulating signal, and also operable for reading said memory module based on said read enable signal.

8. The controller of claim 7, wherein said logic unit comprises:

a counter, operable for storing a count value and for updating said count value based on said trigger signal, wherein said reading and writing unit writes said count value to said memory module based on said write enable signal and said regulating signal.

9. The controller of claim 8, wherein if said switch monitoring signal indicates that said power switch is turned on again within a preset time period after being turned off, then said logic unit generates said write enable signal and said regulating signal, and writes said count value to said memory module using said reading and writing unit.

10. The controller of claim 7, wherein said logic control module further comprises:

a power supply unit, operable for providing a first voltage to enable said reading and writing unit to write to said memory module, and also operable for clamping a voltage at said switch monitoring terminal to a second voltage to turn on said light source module, wherein said first voltage is greater than said second voltage.

11. A light source driving circuit, comprising:

a light source module, comprising a first light source and a second light source; and

a controller, coupled to said light source module, operable for receiving electric power from a power source through a rectifier to power said light source module, said controller comprising a memory module;

wherein said controller is operable for generating a first control signal for turning on said first light source and for turning off said first light source, based on data stored in said memory module; and

wherein said controller is further operable for generating a second control signal for turning on said second light source and for turning off said second light source, based on said data stored in said memory module.

12. The light source driving circuit of claim 11, wherein said memory module comprises:

a first metal-oxide semiconductor capacitor (MOS capacitor);

a second MOS capacitor; and

a metal-oxide semiconductor field effect transistor (MOSFET),

wherein the gate of said first MOS capacitor, the gate of said second MOS capacitor and the gate of said MOSFET are connected together;

wherein the area of said first MOS capacitor is greater than the area of said second MOS capacitor;

wherein the substrate, the source and the drain of said first MOS capacitor are connected together; and

wherein the substrate, the source and the drain of said second MOS capacitor are connected together.

13. The light source driving circuit of claim 11, wherein said controller comprises:

a logic control module, operable for regulating a total current of said light source module by controlling a third switch and also operable for updating said data stored in said memory module based on a switch monitoring signal, wherein said first control signal controls a first switch coupled to said first light source, wherein said second control signal controls a second switch coupled to said second light source, and wherein said switch monitoring signal indicates an on/off state of a power switch coupled between said power source and said rectifier.

14. The light source driving circuit of claim 13, further comprising:

an inductor, coupled between said controller and said light source module;

wherein a current flows through said third switch and said inductor to ground when said third switch is on, wherein a current flows through said inductor, said first light source and said first switch when said third switch is off and said first switch is on, and wherein a current flows through said inductor, said second light source and said second switch when said third switch is off and said second switch is on.

15. The light source driving circuit of claim 13, wherein said logic control module further comprises:

a trigger monitoring unit, operable for generating a trigger signal based on said switch monitoring signal;

a logic unit, operable for generating a read enable signal and a write enable signal based on said switch monitoring signal, and also operable for generating a regulating signal based on said trigger signal; and

a reading and writing unit, operable for writing to said memory module based on said write enable signal and said regulating signal, and also operable for reading said memory module based on said read enable signal.

16. The light source driving circuit of claim 15, wherein said logic unit comprises:

a counter, operable for storing a count value and for updating said count value based on said trigger signal, wherein said reading and writing unit writes said count value to said memory module based on said write enable signal and said regulating signal.

17. The light source driving circuit of claim 15, wherein said logic control module further comprises:

a power supply unit, operable for providing a first voltage to enable said reading and writing unit to write to said memory module, and also operable for clamping a voltage at said switch monitoring terminal to a second voltage to turn on said light source module, wherein said controller receives said switch monitoring signal from said switch monitoring terminal, and wherein said first voltage is greater than said second voltage.

18. A method for controlling a light source module, wherein said light source module comprises a first light source and a second light source, said method comprising:

receiving electric power from a power source at a controller, to power said light source module;

reading data stored in a memory module;

generating a first control signal by said controller based on data stored in said memory module, said first control signal for turning on said first light source and for turning off said first light source; and

generating a second control signal by said controller based on said data stored in said memory module, said second control signal for turning on said second light source and for turning off said second light source.

19. The method of claim 18, further comprising:

receiving a switch monitoring signal indicating an on/off state of a power switch, wherein said power switch is coupled between a power source and a rectifier;

generating a trigger signal based on said switch monitoring signal;

updating a count value of a counter based on said trigger signal; and

writing said count value to said memory module if said switch monitoring signal indicates that said power switch is turned on again within a preset time period after being turned off.

20. The method of claim 19, further comprising:

increasing a voltage at said switch monitoring terminal to a first voltage to enable a write operation to said memory module; and

decreasing said voltage at said switch monitoring terminal to a second voltage to turn on said light source module, wherein said first voltage is greater than said second voltage.