Synchronous light emitting diode lamp string controller

• US 20090273303A1
• Filed: 11/21/2007
• Published: 11/05/2009
• Est. Priority Date: 11/23/2006
• Status: Active Grant

• Current Assignee: Semisilicon Technology Corp.
• Original Assignee: Semisilicon Technology Corp.
• Inventors: Peng, Jacky
• Granted Patent: US 7,928,667 B2
• Time in Patent Office: Days
• US Class Current: 315/297
• CPC Class Codes: H05B 45/30 Driver circuits
• CPC Class Codes: H05B 45/345 Current stabilisation; Maintaining constant current

Abstract

The present invention discloses a synchronous LED lamp string controller, comprising a clock synchronous circuit to receive a reference signal with a constant frequency, and based on which, to generate a system clock; a counter circuit to counter the system clock and generate a clock signal; a control logic circuit to receive said clock signal to generate a control signal; and a driver circuit to receive said control signal to drive at least a light emitting diode.

Claims

1. A synchronous LED lamp string controller, comprising

a clock synchronous circuit for receiving a reference signal with a constant frequency, and based on the reference signal, to generate a system clock;

a counter circuit for counting the system clock and generating a clock signal;

a control logic circuit for receiving the clock signal to generate a control signal; and

a driver circuit for receiving the control signal to drive at least a light emitting diode.

2. The synchronous LED lamp string controller according to claim 1, further comprising a level shifter for receiving said reference signal, the level shifter containing a capacitor to filter the direct current value of said reference signal and retain the alternate current value, harmonizing the alternate current value of said reference signal with the voltage level of said controller by means of voltage biasing, and providing the harmonized reference signal to the clock synchronous circuit.

3. The synchronous LED lamp string controller according to claim 2, wherein the clock synchronous circuit receives the reference signal from the level shifter and synchronize the alternate current value of the reference value with the internal currency of the controller to output said system clock.

4. A synchronous LED lamp string controller, comprising

a recognition circuit for receiving a reference signal with a constant frequency to carry out level shift and voltage biasing and output a recognition signal;

a shift register for receiving and storing the recognition signal;

an encoder circuit for receiving the data stored in the shift register and encoding and outputting said data;

a register for receiving and storing the complete data stored in the shift register; and

a driver circuit for receiving the data stored in the register to drive at least a light emitting diode.

5. The synchronous LED lamp string controller according to claim 4, wherein the recognition circuit uses a capacitor to filter the direct current value of said reference signal and retain the alternate current value, uses a bias resistor to bias the filtered reference signal within the working voltage range of the synchronous LED lamp string controller, uses two voltage comparators each connected with a reference voltage level for comparison with the biased reference signal, and outputs a recognition signal representing the reference signal level being higher than the two reference voltage levels, lower than the two reference voltage levels, or lying between the two reference voltage levels.

6. The synchronous LED lamp string controller according to claim 4, wherein the encoder circuit has an output buffer and a bias resistor, the output power of the output buffer being higher than the output power of said bias resistor, the encoder circuit receiving the data stored in the shift register and outputting the same data via the output buffer, biasing the data output by the output buffer within the working voltage range of the synchronous LED lamp string controller via the bias resistor, and outputting the biased data.

7. A synchronous LED lamp string controller, comprising

a first control logic circuit coupled to a data input pin;

and

a second control logic circuit coupled to a data output pin;

wherein the data input pin and the data output pin represent data logic H, data logic L and data logic M at predefined level, and transmit the same clock transmission data.

8. The synchronous LED lamp string controller according to claim 7, wherein the signals on the data input pin and data output pin have a first level and a third level, and a second level between the first level and the third level, the first level representing the transmission of data logic H, the second level representing the transmission of data logic M, and the third level representing the transmission of data logic L.

9. The synchronous LED lamp string controller according to claim 8, wherein the data output pin outputs data logic M with the second level after outputting data logic H with the first level or data logic L with the third level.

10. A synchronous LED lamp string controller, comprising

a first control logic circuit coupled to a data input pin;

and

a second control logic circuit coupled to a data output pin;

wherein the input pin and the data output pin transmit data logic H signal, data logic L signal and clock signal at predetermined interval.