IP Library Granted Patent US 7,189,949
Granted Patent B1
US 7,189,949 · App. 11/236,144 · Granted Mar 13, 2007

Power control system and method for regulating power provided to a heating device

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Quick Facts
Patent No.
US 7,189,949
App. No.
11/236,144
Granted
Mar 13, 2007
Kind
B1
Abstract

A circuit includes a switching device for controlling a power signal to be applied to a heating device. A control circuit is configured for comparing a temperature signal, indicative of the temperature of the heating device, to a temperature setpoint to generate a gate pulse signal that controls the duration of the power signal to be applied to the heating device. The control circuit is further configured for comparing the duration of the power signal to be applied to the heating device to a minimum pulse duration and, if the duration of the power signal to be applied to the heating device is at least equal to the minimum pulse duration, providing the gate pulse signal to the switching device.

Claims (42)

1. A circuit comprising:

a switching device for controlling a power signal to be applied to a heating device; and

a control circuit configured for comparing a temperature signal, indicative of the temperature of the heating device, to a temperature setpoint to generate a gate pulse signal that controls the duration of the power signal to be applied to the heating device, wherein the control circuit is further configured for comparing the duration of the power signal to be applied to the heating device to a minimum pulse duration of the gate pulse signal and, if the duration of the power signal to be applied to the heating device is at least equal to the minimum pulse duration, providing the gate pulse signal to the switching device.

2. The circuit of claim 1 further comprising:

a temperature monitoring device for generating the temperature signal.

3. The circuit of claim 2 wherein the temperature monitoring device includes a thermistor.

4. The circuit of claim 1 wherein the control circuit is further configured for discarding the gate pulse signal if the duration of the power signal to be applied to the heating device is less than the minimum pulse duration.

5. The circuit of claim 1 wherein the switching device includes a triac.

6. The circuit of claim 1 wherein the switching device includes a silicon controlled rectifier.

7. The circuit of claim 1 wherein the power signal to be applied to the heating device is an AC power signal and the switching device is configured to provide the AC power signal to the heating device upon receiving the gate pulse signal and to continue to provide the AC power signal to the heating device until the AC power signal changes polarity.

8. An assembly comprising:

a heating device;

a switching device for controlling a power signal to be applied to the heating device; and

a control circuit configured for comparing a temperature signal, indicative of the temperature of the heating device, to a temperature setpoint to generate a gate pulse signal that controls the duration of the power signal to be applied to the heating device, wherein the control circuit is further configured for comparing the duration of the power signal to be applied to the heating device to a minimum pulse duration of the gate pulse signal and, if the duration of the power signal to be applied to the heating device is at least equal to the minimum pulse duration, providing the gate pulse signal to the switching device.

9. The assembly of claim 8 further comprising:

a temperature monitoring device for generating the temperature signal.

10. The assembly of claim 8 wherein the control circuit is further configured for discarding the gate pulse signal if the duration of the power signal to be applied to the heating device is less than the minimum pulse duration.

11. The assembly of claim 8 wherein the power signal to be applied to the heating device is an AC power signal and the switching device is configured to provide the AC power signal to the heating device upon receiving the gate pulse signal and to continue to provide the AC power signal to the heating device until the AC power signal changes polarity.

12. A method comprising:

comparing a temperature signal, indicative of the temperature of a heating device, to a temperature setpoint to generate a gate pulse signal that controls the duration of a power signal to be applied to the heating device;

comparing the duration of the power signal to be applied to the heating device to a minimum pulse duration of the gate pulse signal; and

providing the gate pulse signal to a switching device if the duration of the power signal to be applied to the heating device is at least equal to the minimum pulse duration, wherein the switching device is configured to control the power signal to be applied to the heating device.

13. The method of claim 12 further comprising:

generating the temperature signal using a temperature monitoring device.

14. The method of claim 13 wherein the temperature monitoring device includes a thermistor.

15. The method of claim 12 further comprising:

discarding the gate pulse signal if the duration of the power signal to be applied to the heating device is less than the minimum pulse duration.

16. The method of claim 12 wherein the switching device includes a triac.

17. The method of claim 12 wherein the switching device includes a silicon controlled rectifier.

18. The method of claim 12 wherein the power signal to be applied to the heating device is an AC power signal and the switching device is configured to provide the AC power signal to the heating device upon receiving the gate pulse signal and to continue to provide the AC power signal to the heating device until the AC power signal changes polarity.

19. A computer program product residing on a computer readable medium having a plurality of instructions stored thereon which, when executed by a processor, cause the processor to:

compare a temperature signal, indicative of the temperature of a heating device, to a temperature setpoint to generate a gate pulse signal that controls the duration of a power signal to be applied to the heating device;

compare the duration of the power signal to be applied to the heating device to a minimum pulse duration of the gate pulse signal; and

provide the gate pulse signal to a switching device if the duration of the power signal to be applied to the heating device is at least equal to the minimum pulse duration, wherein the switching device is configured to control the power signal to be applied to the heating device.

20. The computer program product of claim 19 further comprising instructions for:

generating the temperature signal using a temperature monitoring device.

21. The computer program product of claim 20 wherein the temperature monitoring device includes a thermistor.

22. The computer program product of claim 19 further comprising instructions for:

discarding the gate pulse signal if the duration of the power signal to be applied to the heating device is less than the minimum pulse duration.

23. The computer program product of claim 19 wherein the switching device includes a triac.

24. The computer program product of claim 19 wherein the switching device includes a silicon controlled rectifier.

25. The computer program product of claim 19 wherein the power signal to be applied to the heating device is an AC power signal and the switching device is configured to provide the AC power signal to the heating device upon receiving the gate pulse signal and to continue to provide the AC power signal to the heating device until the AC power signal changes polarity.

Assignments (7)
SECURITY INTEREST Recorded Jan 5, 2026
From: LEXMARK INTERNATIONAL, INC.
To: BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 074202/0192 →
SECURITY INTEREST Recorded Jan 5, 2026
From: LEXMARK INTERNATIONAL, INC.
To: BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 074202/0293 →
SECURITY INTEREST Recorded Sep 23, 2025
From: LEXMARK INTERNATIONAL, INC.
To: CITIBANK, N.A.
Reel/Frame 073007/0118 →
SECURITY INTEREST Recorded Sep 23, 2025
From: LEXMARK INTERNATIONAL, INC.
To: JEFFERIES FINANCE LLC
Reel/Frame 073007/0346 →
RELEASE OF SECURITY INTEREST Recorded Jan 18, 2024
From: CHINA CITIC BANK CORPORATION LIMITED, GUANGZHOU BRANCH, AS COLLATERAL AGENT
To: LEXMARK INTERNATIONAL, INC.
Reel/Frame 066345/0026 →
CORRECTIVE ASSIGNMENT TO CORRECT THE INCORRECT U.S. PATENT NUMBER PREVIOUSLY RECORDED AT REEL: 046989 FRAME: 0396. ASSIGNOR(S) HEREBY CONFIRMS THE PATENT SECURITY AGREEMENT. Recorded Oct 24, 2018
From: LEXMARK INTERNATIONAL, INC.
To: CHINA CITIC BANK CORPORATION LIMITED, GUANGZHOU BRANCH, AS COLLATERAL AGENT
Reel/Frame 047760/0795 →
PATENT SECURITY AGREEMENT Recorded Aug 30, 2018
From: LEXMARK INTERNATIONAL, INC.
To: CHINA CITIC BANK CORPORATION LIMITED, GUANGZHOU BRANCH, AS COLLATERAL AGENT
Reel/Frame 046989/0396 →