Power supply monitor

• US 4,245,289 A
• Filed: 10/25/1978
• Issued: 01/13/1981
• Est. Priority Date: 10/25/1978
• Status: Expired due to Term

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Mohr, Glen E., Mineck, David W.
• Primary Examiner(s): Beha, Jr., William H.
• Application Number:
  US05/954,394
• Time in Patent Office: 811 Days
• Field of Search: 363/25, 363/26, 363/41, 363/55, 363/56, 363/57, 363/96, 363/97, 323/17, 323/DIG. 1, 340/659, 307/234
• US Class Current: 363/41
• CPC Class Codes: H02M 3/3378 in a push-pull configuration of the parallel type H02M3/3374 takes precedence

Abstract

In a duty cycle modulated power regulating apparatus, loss of regulation is anticipated by monitoring the duty cycle of the regulating means.

Claims

1. Apparatus comprising (i) duty cycle modulated power regulating means for, in accordance with a duty cycle, alternately allowing, for a variable time T_x, and inhibiting, for a variable time T_y, contribution of an unregulated DC source to the regulating means output, said T_x varying in response to variation in said unregulated DC source so that a substantially constant voltage-time area per (T_x +T_y) interval is maintained at the regulating means output, and (ii) detection means for monitoring said duty cycle and providing a signal indicative of the value of said duty cycle.

2. Apparatus as defined in claim 1 wherein said signal indicative of the value of said duty cycle is a signal which changes from a first constant level to a second constant level upon the occurrence of said duty cycle exceeding a predetermined duty cycle value M₁.

3. Apparatus as defined in claim 2 wherein said signal indicative of the value of said duty cycle is a signal which, after having changed to said second constant level, changes back to said first constant level upon the occurrence of said duty cycle dropping back below a predetermined duty cycle value M₂.

4. Apparatus as defined in claim 3 wherein M₂ is not equal to M₁.

5. Apparatus as defined in claim 4 wherein M₁ is greater than M₂.

6. Apparatus as defined in claim 5 wherein said detection means is hysteretic, whereby, inequality between M₁ and M₂ is effected.

7. Apparatus as defined in claim 1 wherein each time interval (T_x +T_y) equals T_k, where T_k is a predetermined constant time interval, and said detection means for monitoring said duty cycle and providing a signal indicative of the value of said duty cycle comprises means for monitoring a predetermined one of times T_x or T_y and providing a signal indicative of the duration of the monitored one of T_x or T_y.

8. Apparatus as defined in claim 7 wherein said signal indicative of the duration of the monitored one of T_x or T_y is a signal having a first constant level when the duration of the monitored one of T_x or T_y is less than a reference duration T_f and having a second constant level when the duration of the monitored one of T_x or T_y is greater than said reference duration T_f.

9. Apparatus as defined in claim 8 wherein said detection means includes hysteresis providing means for altering the reference duration T_f.

10. Apparatus as defined in claim 7 wherein the predetermined one of times T_x or T_y is the one of T_x or T_y which is usually shorter than the other.

11. Apparatus as defined in claim 1 wherein each time interval (T_x +T_y) equals T_k, where T_k isa predetermined constant time interval, and said detection means for monitoring said duty cycle and providing a signal indicative of the value of said duty cycle comprises means for monitoring T_y and providing a signal indicative of the duration of T_y.

12. Apparatus as defined in claim 11 wherein said signal indicative of the duration of T_y is a signal which changes from a first constant level to a second constant level when T_y becomes less than a reference duration T_q.

13. Apparatus as defined in claim 11 wherein said signal indicative of the duration of T_y is a signal which changes from a first constant level to a second constant level when T_y becomes less than a reference duration T_q and thereafter changes back to said first constant level when T_y becomes greater than a reference duration T_p.

14. Apparatus as defined in claim 13 wherein T_p is not equal to T_q.

15. Apparatus as defined in claim 14 wherein T_p is greater than T_q.

16. Apparatus as defined in claim 15 wherein said detection means is hysteretic, whereby, inequality between T_p and T_q is effected.