LED lighting control integrated circuit having embedded programmable nonvolatile memory

• US 7,999,491 B2
• Filed: 12/02/2008
• Issued: 08/16/2011
• Est. Priority Date: 12/02/2008
• Status: Active Grant

• Current Assignee: Ememory Technology Inc.
• Original Assignee: Ememory Technology Inc.
• Inventors: Peng, Sheng-Kai, Sun, Wein-Town
• Primary Examiner(s): Owens; Douglas W
• Assistant Examiner(s): A; Minh D
• Application Number:
  US12/326,872
• Publication Number:
  US 20100134020A1
• Time in Patent Office: 987 Days
• Field of Search: 315/291, 315/307, 315/224, 315/209.R, 315/312
• US Class Current: 315/291
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/28 using temperature feedback

Abstract

For providing a compact high-precision lighting control means to drive an LED lighting module, a lighting control integrated circuit is set forth to perform an accurate lighting control. At least one nonvolatile memory is embedded in the lighting control integrated circuit for storing a plurality of lookup tables. One lookup table provides related data for setting the driving currents of the LED lighting module based on spacing or pitch of LED disposition of the LED lighting module. Another lookup table provides related data to recover uniformity for different LED damage situations of the LED lighting module. The other lookup tables are applied to perform compensation processes on the driving currents concerning temperature variation, ambient light intensity, aging degradation, and power-on time. In addition, a signal processing unit, a pulse-width-modulation signal generating module, and a driving module are incorporated in the lighting control integrated circuit for signal processing and current driving.

Claims

1. An LED lighting control integrated circuit comprising:

a first nonvolatile memory;

a plurality of first lookup tables stored in the first nonvolatile memory comprising a current setting and trimming lookup table for providing a plurality of current setting and trimming calibration signals based on spacing or pitch of LED disposition of an LED lighting module;

a first timer for counting an elapsed operating time of the LED lighting module each time after power-on;

a second nonvolatile memory coupled to the first timer;

a power-on-time-related lookup table, stored in the second nonvolatile memory, for providing a plurality of power-on-time-related compensation signals based on the elapsed operating time;

a signal processing unit, coupled to the first nonvolatile memory and the second nonvolatile memory, for generating a plurality of sets of control signals based on the plurality of current setting and trimming calibration signals in conjunction with the power-on-time-related compensation signals;

a pulse-width-modulation (PWM) signal generating module coupled to the signal processing unit for generating a plurality of sets of PWM signals, the PWM signal generating module comprising;

a plurality of PWM signal generators for generating the plurality of sets of PWM signals based on the plurality of sets of control signals respectively; and

a driving module coupled to the PWM signal generating module for providing a plurality of sets of currents to the LED lighting module, the driving module comprising;

a plurality of driving circuits coupled to the plurality of PWM signal generators respectively for providing the plurality of sets of currents to the LED lighting module based on the plurality of sets of PWM signals respectively.

2. The LED lighting control integrated circuit of claim 1, further comprising:

a second timer, coupled to the second nonvolatile memory, for counting an accumulated operating time of the LED lighting module; and

a plurality of second lookup tables stored in the second nonvolatile memory, the plurality of second lookup tables comprising;

a degradation-related lookup table for providing a plurality of degradation-related compensation signals based on the accumulated operating time or a plurality of color sensing signals in digital form;

an ambient-light-related lookup table for providing a plurality of ambient-light-related compensation signals based on an ambient light sensing signal in digital form;

or

a temperature-related lookup table for providing a plurality of temperature-related compensation signals based on a temperature sensing signal in digital form;

wherein the signal processing unit generates the plurality of sets of control signals further based on the plurality of degradation-related compensation signals, the plurality of ambient-light-related compensation signals, or the plurality of temperature-related compensation signals.

3. The LED lighting control integrated circuit of claim 2, wherein:

the second timer comprises a multiple time programmable nonvolatile memory or a pseudo multiple time programmable nonvolatile memory for storing the accumulated operating time;

the first nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory; and

the second nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory;

wherein the LED lighting control integrated circuit is fabricated based on a Bipolar-CMOS-DMOS IC fabrication process or a High-Voltage IC fabrication process, and fabrication processes of the one time programmable nonvolatile memory, the pseudo multiple time programmable nonvolatile memory, and the multiple time programmable nonvolatile memory are compatible to the Bipolar-CMOS-DMOS IC fabrication process or the High-Voltage IC fabrication process.

4. The LED lighting control integrated circuit of claim 2, further comprising:

a first analog-to-digital converter coupled to the second nonvolatile memory for converting a temperature sensing signal in analog form to the temperature sensing signal in digital form;

a second analog-to-digital converter coupled to the second nonvolatile memory for converting an ambient light sensing signal in analog form to the ambient light sensing signal in digital form;

or

a plurality of third analog-to-digital converters coupled to the second nonvolatile memory for converting a plurality of color sensing signals in analog form to the plurality of color sensing signals in digital form.

5. The LED lighting control integrated circuit of claim 1, wherein:

the plurality of first lookup tables further comprise a voltage setting and trimming lookup table for providing a voltage setting and trimming calibration signal to the signal processing unit based on a number of series-connected LED sub-units in each LED unit of the LED lighting module, wherein the signal processing unit generates a voltage control signal based on the voltage setting and trimming calibration signal; and

the driving module further comprises a voltage driving circuit coupled to the signal processing unit for providing a common voltage to the LED lighting module based on the voltage control signal.

6. The LED lighting control integrated circuit of claim 1, further comprising:

a third nonvolatile memory coupled to the signal processing unit;

a uniformity-recovery lookup table stored in the third nonvolatile memory for providing a plurality of uniformity-recovery compensation signals to the signal processing unit according to an LED damage situation of the LED lighting module, the uniformity-recovery lookup table being created based on predetermined uniformity-recovery regulations for recovering spatial uniformity of chromaticity and luminance concerning a variety of LED damage situations of the LED lighting module; and

a current sensing unit coupled to the third nonvolatile memory and the plurality of driving circuits for generating a plurality of current sensing signals based on the plurality of sets of currents, wherein the LED damage situation of the LED lighting module is determined based on the plurality of current sensing signals;

wherein the third nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory, and the signal processing unit generates the plurality of sets of control signals based on the plurality of current setting and trimming calibration signals in conjunction with the plurality of uniformity-recovery compensation signals.

7. The LED lighting control integrated circuit of claim 1, wherein:

the signal processing unit comprises;

a plurality of first buffers for outputting the plurality of sets of control signals respectively in serial-transmitting mode; and

the PWM signal generating module further comprises;

a plurality of second buffers coupled between the plurality of first buffers and the plurality of PWM signal generators respectively for receiving the plurality of sets of serially transmitted control signals.

8. An LED lighting control integrated circuit comprising:

a first nonvolatile memory;

a plurality of first lookup tables stored in the first nonvolatile memory comprising

a uniformity-recovery lookup table for providing a plurality of uniformity-recovery compensation signals according to an LED damage situation of an LED lighting module, the uniformity-recovery lookup table being created based on predetermined uniformity-recovery regulations for recovering spatial uniformity of chromaticity and luminance concerning a variety of LED damage situations of the LED lighting module;

a signal processing unit coupled to the first nonvolatile memory for generating a plurality of sets of control signals based on the plurality of uniformity-recovery compensation signals;

a pulse-width-modulation signal generating module coupled to the signal processing unit for generating a plurality of sets of PWM signals, the PWM signal generating module comprising;

a plurality of PWM signal generators for generating the plurality of sets of PWM signals based on the plurality of sets of control signals respectively;

a driving module coupled to the PWM signal generating module for providing a plurality of sets of currents to the LED lighting module, the driving module comprising;

a plurality of driving circuits coupled to the plurality of PWM signal generators respectively for providing the plurality of sets of currents to the LED lighting module based on the plurality of sets of PWM signals respectively; and

a current sensing unit coupled to the first nonvolatile memory and the plurality of driving circuits for generating a plurality of current sensing signals based on the plurality of sets of currents;

wherein the LED damage situation of the LED lighting module is determined based on the plurality of current sensing signals.

9. The LED lighting control integrated circuit of claim 8, further comprising:

a first timer for counting an elapsed operating time of the LED lighting module each time after power-on;

a second timer for counting an accumulated operating time of the LED lighting module;

a second nonvolatile memory coupled to the signal processing unit, the first timer, and the second timer; and

a plurality of second lookup tables stored in the second nonvolatile memory, the plurality of second lookup tables comprising;

a power-on-time-related lookup table for providing a plurality of power-on-time-related compensation signals based on the elapsed operating time;

a degradation-related lookup table for providing a plurality of degradation-related compensation signals based on the accumulated operating time or a plurality of color sensing signals in digital form;

an ambient-light-related lookup table for providing a plurality of ambient-light-related compensation signals based on an ambient light sensing signal in digital form;

or

a temperature-related lookup table for providing a plurality of temperature-related compensation signals based on a temperature sensing signal in digital form;

wherein the signal processing unit generates the plurality of sets of control signals based on the plurality of uniformity-recovery compensation signals in conjunction with the plurality of power-on-time-related compensation signals, the plurality of degradation-related compensation signals, the plurality of ambient-light-related compensation signals, or the plurality of temperature-related compensation signals.

10. The LED lighting control integrated circuit of claim 9, wherein:

the second timer comprises a multiple time programmable nonvolatile memory or a pseudo multiple time programmable nonvolatile memory for storing the accumulated operating time;

the first nonvolatile memory is a multiple time programmable nonvolatile memory or a one time programmable nonvolatile memory; and

the second nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory;

wherein the LED lighting control integrated circuit is fabricated based on a Bipolar-CMOS-DMOS IC fabrication process or a High-Voltage IC fabrication process, and fabrication processes of the one time programmable nonvolatile memory, the pseudo multiple time programmable nonvolatile memory, and the multiple time programmable nonvolatile memory are compatible to the Bipolar-CMOS-DMOS IC fabrication process or the High-Voltage IC fabrication process.

11. The LED lighting control integrated circuit of claim 9, further comprising:

a first analog-to-digital converter coupled to the second nonvolatile memory for converting a temperature sensing signal in analog form to the temperature sensing signal in digital form;

a second analog-to-digital converter coupled to the second nonvolatile memory for converting an ambient light sensing signal in analog form to the ambient light sensing signal in digital form;

or

a plurality of third analog-to-digital converter coupled to the second nonvolatile memory for converting a plurality of color sensing signals in analog form to the plurality of color sensing signals in digital form.

12. The LED lighting control integrated circuit of claim 8, wherein:

the plurality of first lookup tables further comprise a voltage setting and trimming lookup table for providing a voltage setting and trimming calibration signal to the signal processing unit based on a number of series-connected LED sub-units in each LED unit of the LED lighting module, wherein the signal processing unit generates a voltage control signal based on the voltage setting and trimming calibration signal; and

the driving module further comprises a voltage driving circuit coupled to the signal processing unit for providing a common voltage to the LED lighting module based on the voltage control signal.

13. The LED lighting control integrated circuit of claim 8, wherein:

the signal processing unit comprises;

a plurality of first buffers for outputting the plurality of sets of control signals respectively in serial-transmitting mode; and

the PWM signal generating module further comprises;

a plurality of second buffers coupled between the plurality of first buffers and the plurality of PWM signal generators respectively for receiving the plurality of sets of serially transmitted control signals.

14. An LED lighting control integrated circuit comprising:

a first nonvolatile memory;

a uniformity-recovery lookup table stored in the first nonvolatile memory for providing a plurality of uniformity-recovery compensation signals according to an LED damage situation of an LED lighting module, the uniformity-recovery lookup table being created based on predetermined uniformity-recovery regulations for recovering spatial uniformity of chromaticity and luminance concerning a variety of LED damage situations of the LED lighting module;

a signal processing unit coupled to the first nonvolatile memory for generating a plurality of sets of control signals based on the plurality of uniformity-recovery compensation signals;

a pulse-width-modulation signal generating module coupled to the signal processing unit for generating a plurality of sets of PWM signals, the PWM signal generating module comprising;

a plurality of PWM signal generators for generating the plurality of sets of PWM signals based on the plurality of sets of control signals respectively;

a driving module coupled to the PWM signal generating module for providing a plurality of sets of currents and a plurality of common voltages to the LED lighting module, the driving module comprising;

a plurality of driving circuits coupled to the plurality of PWM signal generators respectively for providing the plurality of sets of currents to the LED lighting module based on the plurality of sets of PWM signals respectively; and

a voltage driving circuit coupled to the signal processing unit for providing a plurality of common voltages to the LED lighting module based on a voltage control signal generated by the signal processing unit; and

a current sensing unit coupled to the first nonvolatile memory, the voltage driving circuit, and the plurality of driving circuits for generating a plurality of current sensing signals based on the plurality of sets of currents and a plurality of output currents from the voltage driving circuit;

wherein the LED damage situation of the LED lighting module is determined based on the plurality of current sensing signals.

15. The LED lighting control integrated circuit of claim 14, further comprising:

a second nonvolatile memory coupled to the signal processing unit; and

a plurality of first lookup tables stored in the second nonvolatile memory, the plurality of first lookup tables comprising;

a current setting and trimming lookup table for providing a plurality of current setting and trimming calibration signals based on spacing or pitch of LED disposition of the LED lighting module; and

a voltage setting and trimming lookup table for providing a voltage setting and trimming calibration signal to the signal processing unit based on a number of series-connected LED sub-units in each LED unit of the LED lighting module;

wherein the signal processing unit generates the plurality of sets of control signals based on the plurality of uniformity-recovery compensation signals and the plurality of current setting and trimming calibration signals, and the signal processing unit generates the voltage control signal based on the voltage setting and trimming calibration signal.

16. The LED lighting control integrated circuit of claim 15, wherein:

the first nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory;

the second nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory; and

the LED lighting control integrated circuit is fabricated based on a Bipolar-CMOS-DMOS IC fabrication process or a High-Voltage IC fabrication process, and fabrication processes of the one time programmable nonvolatile memory and the multiple time programmable nonvolatile memory are compatible to the Bipolar-CMOS-DMOS IC fabrication process or the High-Voltage IC fabrication process.

17. The LED lighting control integrated circuit of claim 14, further comprising:

a first timer for counting an elapsed operating time of the LED lighting module each time after power-on;

a second timer for counting an accumulated operating time of the LED lighting module;

a third nonvolatile memory coupled to the signal processing unit, the first timer, and the second timer; and

a plurality of second lookup tables stored in the third nonvolatile memory, the plurality of second lookup tables comprising;

a power-on-time-related lookup table for providing a plurality of power-on-time-related compensation signals based on the elapsed operating time;

a degradation-related lookup table for providing a plurality of degradation-related compensation signals based on the accumulated operating time or a plurality of color sensing signals in digital form;

an ambient-light-related lookup table for providing a plurality of ambient-light-related compensation signals based on an ambient light sensing signal in digital form;

or

a temperature-related lookup table for providing a plurality of temperature-related compensation signals based on a temperature sensing signal in digital form;

wherein the signal processing unit generates the plurality of sets of control signals based on the plurality of uniformity-recovery compensation signals in conjunction with the plurality of power-on-time-related compensation signals, the plurality of degradation-related compensation signals, the plurality of ambient-light-related compensation signals, or the plurality of temperature-related compensation signals.

18. The LED lighting control integrated circuit of claim 17, wherein:

the second timer comprises a multiple time programmable nonvolatile memory or a pseudo multiple time programmable nonvolatile memory for storing the accumulated operating time;

the first nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory;

the third nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory; and

the LED lighting control integrated circuit is fabricated based on a Bipolar-CMOS-DMOS IC fabrication process or a High-Voltage IC fabrication process, and fabrication processes of the one time programmable nonvolatile memory, the pseudo multiple time programmable nonvolatile memory, and the multiple time programmable nonvolatile memory are compatible to the Bipolar-CMOS-DMOS IC fabrication process or the High-Voltage IC fabrication process.

19. The LED lighting control integrated circuit of claim 17, further comprising:

a first analog-to-digital converter coupled to the third nonvolatile memory for converting a temperature sensing signal in analog form to the temperature sensing signal in digital form;

a second analog-to-digital converter coupled to the third nonvolatile memory for converting an ambient light sensing signal in analog form to the ambient light sensing signal in digital form;

or

a plurality of third analog-to-digital converters coupled to the third nonvolatile memory for converting a plurality of color sensing signals in analog form to the plurality of color sensing signals in digital form.

20. The LED lighting control integrated circuit of claim 14, wherein:

the signal processing unit comprises;

a plurality of first buffers for outputting the plurality of sets of control signals respectively in serial-transmitting mode; and

the PWM signal generating module further comprises;

a plurality of second buffers coupled between the plurality of first buffers and the plurality of PWM signal generators respectively for receiving the plurality of sets of serially transmitted control signals.

21. An LED lighting control integrated circuit comprising:

a first nonvolatile memory;

a current setting and trimming lookup table, stored in the first nonvolatile memory, for providing a plurality of current setting and trimming calibration signals based on spacing or pitch of LED disposition of an LED lighting module;

a second nonvolatile memory;

a uniformity-recovery lookup table, stored in the second nonvolatile memory, for providing a plurality of uniformity-recovery compensation signals to the signal processing unit according to an LED damage situation of the LED lighting module, the uniformity-recovery lookup table being created based on predetermined uniformity-recovery regulations for recovering spatial uniformity of chromaticity and luminance concerning a variety of LED damage situations of the LED lighting module;

a signal processing unit, coupled to the first nonvolatile memory and the second nonvolatile memory, for generating a plurality of sets of control signals based on the current setting and trimming calibration signals in conjunction with the uniformity-recovery compensation signals;

a pulse-width-modulation (PWM) signal generating module, coupled to the signal processing unit, for generating a plurality of sets of PWM signals, the PWM signal generating module comprising;

a plurality of PWM signal generators for generating the plurality of sets of PWM signals based on the plurality of sets of control signals respectively;

a driving module, coupled to the PWM signal generating module, for providing a plurality of sets of currents to the LED lighting module, the driving module comprising;

a plurality of driving circuits coupled to the plurality of PWM signal generators respectively for providing the plurality of sets of currents to the LED lighting module based on the plurality of sets of PWM signals respectively; and

a current sensing unit, coupled to the second nonvolatile memory and the plurality of driving circuits, for generating a plurality of current sensing signals based on the plurality of sets of currents, wherein the LED damage situation of the LED lighting module is determined based on the plurality of current sensing signals;

wherein the second nonvolatile memory is a one time programmable nonvolatile memory or a multiple time programmable nonvolatile memory.

22. An LED lighting control integrated circuit comprising:

a first nonvolatile memory;

a current setting and trimming lookup table, stored in the first nonvolatile memory, for providing a plurality of current setting and trimming calibration signals based on spacing or pitch of LED disposition of an LED lighting module;

a timer for counting an accumulated operating time of the LED lighting module;

a second nonvolatile memory coupled to the timer;

a degradation-related lookup table, stored in the second nonvolatile memory, for providing a plurality of degradation-related compensation signals based on the accumulated operating time or a plurality of color sensing signals in digital form;

a signal processing unit , coupled to the first nonvolatile memory and the second nonvolatile memory, for generating a plurality of sets of control signals based on the plurality of current setting and trimming calibration signals in conjunction with the degradation-related compensation signals;

a pulse-width-modulation (PWM) signal generating module, coupled to the signal processing unit, for generating a plurality of sets of PWM signals, the PWM signal generating module comprising;

a plurality of PWM signal generators for generating the plurality of sets of PWM signals based on the plurality of sets of control signals respectively; and

a driving module, coupled to the PWM signal generating module, for providing a plurality of sets of currents to the LED lighting module, the driving module comprising;

a plurality of driving circuits coupled to the plurality of PWM signal generators respectively for providing the plurality of sets of currents to the LED lighting module based on the plurality of sets of PWM signals respectively.