Sequential burst mode activation circuit

• US 7,847,491 B2
• Filed: 01/12/2009
• Issued: 12/07/2010
• Est. Priority Date: 01/09/2001
• Status: Expired due to Fees

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Lin, Yung-Lin, Chang, Yu-Cheng, Yao, Bingwei
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): A, Minh D
• Application Number:
  US12/321,092
• Publication Number:
  US 20090218954A1
• Time in Patent Office: 694 Days
• Field of Search: 315/307, 315/291, 315/308, 315/312, 315/314
• US Class Current: 315/307
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H05B 41/3927 by pulse width modulation H05B41/3922 takes precedence

Abstract

A sequential burst mode regulation system to deliver power to a plurality of loads. In the exemplary embodiments, the system of the present invention generates a plurality of phased pulse width modulated signals from a single pulse width modulated signal, where each of the phased signals regulates power to a respective load. Exemplary circuitry includes a PWM signal generator, and a phase delay array that receives a PWM signal and generates a plurality of phased PWM signals which are used to regulate power to respective loads. A frequency selector circuit can be provided that sets the frequency of the PWM signal using a fixed or variable frequency reference signal.

Claims

1. A light source power regulation system, comprising:

a phase delay array for receiving a frequency selection signal and a pulse-width modulated signal and for generating a plurality of phase-shifted pulse width modulated signals having a frequency determined by said frequency selection signal, and for determining a phase delay of said phase-shifted pulse width modulated signals, wherein each said phase-shifted pulse width modulated signal regulates power to a respective light source of a plurality of light sources; and

a plurality of phase array drivers coupled to said phase delay array and for receiving said phase-shifted pulse width modulated signals and generating a plurality of power regulating signals to regulate power to said light sources respectively based on said pulse width of said phase-shifted pulse width modulated signals,

wherein at least one of said power regulating signals has a phase value equal to the phase value of a corresponding phase-shifted pulse width modulated signal.

2. A light source power regulation system as claimed in claim 1, wherein said pulse width of said phase-shifted pulse width modulated signals is determined by a pulse width of the pulse width modulated signal received by said pulse delay array.

3. A light source power regulation system as claimed in claim 1, wherein said pulse-width modulated signal is provided by a modulator coupled to said phase delay array, and wherein said modulator adjusts said pulse width of said phase-shifted pulse width modulated signals according to a pulse width of the pulse width modulated signal.

4. A light source power regulation system as claimed in claim 3, wherein said modulator further comprises a variable selector for setting said pulse width of said pulse width modulated signal from said modulator.

5. A light source power regulation system as claimed in claim 1, further comprising:

a frequency selector for receiving a reference signal and generating a frequency selection signal based on said reference signal,

wherein said phase delay array receives said frequency selection signal and sets the frequency of said phase-shifted pulse width modulated signals based on said frequency selection signal.

6. A light source power regulation system as claimed in claim 1, wherein said light sources comprise a plurality of light-emitting diodes.

7. A system comprising:

a display panel;

a plurality of light-emitting diodes for lighting said display panel; and

a driving system for powering said light-emitting diodes, comprising;

a phase delay array for receiving a frequency selection signal and a pulse-width modulated signal and for generating a plurality of phase-shifted pulse width modulated signals having a frequency determined by said frequency selection signal, wherein each said phase-shifted pulse width modulated signal regulates power to a respective light-emitting diode; and

a plurality of phase array drivers coupled to said phase delay array and for receiving said phase-shifted pulse width modulated signals and generating a plurality of power regulating signals to regulate power to said plurality of light-emitting diodes respectively based on said pulse width of said phase-shifted pulse width modulated signals,

wherein at least one of said power regulating signals has a phase value equal to the phase value of a corresponding phase-shifted pulse width modulated signal.

8. A system as claimed in claims 7, wherein said pulse width of said phase-shifted pulse width modulated signals is determined by a pulse width of the pulse width modulated signal received by said phase delay array.

9. A system as claimed in claim 7, wherein said pulse-width modulated signal is provided by a modulator coupled to said phase delay array, and wherein said modulator adjusts said pulse width of said phase-shifted pulse width modulated signals according to a pulse width of the pulse-width modulated signal.

10. A system as claimed in claim 9, wherein said modulator further comprises a variable selector for setting said pulse width of said pulse width modulated signal from said modulator, thereby setting the brightness of each of said light-emitting diodes.

11. A system as claimed in claim 7, further comprising:

a frequency selector for receiving a reference signal and generating a frequency selection signal based on said reference signal,

wherein said phase delay array receives said frequency selection signal and sets the frequency of said phase-shifted pulse width modulated signals based on said frequency selection signal.

12. A system as claimed in claim 7, wherein said display panel comprises an LCD.

13. A display comprising:

a plurality of light-emitting diodes for lighting said display; and

a driving system for powering said light-emitting diodes, comprising;

a phase delay array for receiving a frequency selection signal and a pulse-width modulated signal and for generating a plurality of phase-shifted pulse width modulated signals having a frequency of said frequency selection signal, wherein each said phase-shifted pulse width modulated signal regulates power to a respective light-emitting diode; and

a plurality of phase array drivers coupled to said phase delay array and for receiving said phase-shifted pulse width modulated signals and generating a plurality of power regulating signals to regulate power to said light-emitting diodes respectively based on said pulse width of said phase-shifted pulse width modulated signals,

wherein at least one of said power regulating signals has a phase value equal to the phase value of a corresponding phase-shifted pulse width modulated signal.

14. A display as claimed in claim 13, wherein said pulse width of said phase-shifted pulse width modulated signals is determined by a pulse width of the pulse width modulated signal received by said phase delay array.

15. A display as claimed in claim 13, wherein said pulse-width modulated signal is provided by a modulator coupled to said phase delay array, and wherein said modulator adjusts said pulse width of said phase-shifted pulse width modulated signals according to a pulse width of the pulse width modulated signal.

16. A display as claimed in claim 15, wherein said modulator further comprises a variable selector for setting said pulse width of said pulse width modulated signal from said modulator, thereby setting the brightness of each of said light-emitting diodes.

17. A display as claimed in claim 13, further comprising:

a frequency selector for receiving a reference signal and generating a frequency selection signal based on said reference signal,

wherein said phase delay array receives said frequency selection signal and sets the frequency of said phase-shifted pulse width modulated signals based on said frequency selection signal.