US4288831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shutdown circuit for a switching power supply
Assignee: Motorola Solutions Inc
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Filing: 1979-12-12
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Granted: 1981-09-08
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Expires: 1999-12-12
Abstract
Abstract A switching mode power supply provides a D.C. output voltage having a value related to the duty cycle of the supply's controlled oscillator produced signal. The inventive shutdown circuit inhibits operation of the supply if the duty cycle increases to a value indicative of failure of the supply to produce a minimum desired output voltage. Operation of the supply is inhibited for a predetermined shutdown interval following which a restart cycle deactivates the shutdown circuit for a period to allow the supply to attempt to establish its desired output.
Inventors
- 👤 Arman V. Dolikian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:24
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33507; H02H; H02H7/00; H02H7/10; H02H7/12
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
107 words
A shutdown circuit for a switching type power supply having a fixed reference oscillator with an output wherein the voltage produced by the supply is a function of the output from a controlled oscillator, comprising: low voltage sense means for comparing the output of the controlled oscillator to the output of the fixed reference oscillator, and generating an inhibit signal in response to a predetermined relationship between the fixed reference oscillator output and the output from the controlled oscillator; shutdown timer means coupled to the low voltage sense means for inhibiting operation of the power supply for a predetermined time interval in response to said inhibit signal.
Claim 2
Dependent Claim
107 words
A shutdown circuit for a switching type power supply having a fixed reference oscillator with an output wherein the voltage produced by the supply is a function of the output from a controlled oscillator, comprising: low voltage sense means for comparing the output of the controlled oscillator to the output of the fixed reference oscillator, and generating an inhibit signal in response to a predetermined relationship between the fixed reference oscillator output and the output from the controlled oscillator; shutdown timer means coupled to the low voltage sense means for inhibiting operation of the power supply for a predetermined time interval in response to said inhibit signal.
Claim 3
Dependent Claim
70 words
The shutdown circuit of claim 1 wherein the controlled oscillator produces a variable duty cycle signal for controlling the power supply produced voltage, and the fixed reference oscillator has a fixed duty cycle, wherein the low voltage sense means comprises means for generating the inhibit signal in response to a predetermined relationship between the duty cycle of the controlled oscillator and the fixed duty cycle of the fixed reference oscillator
Claim 4
Dependent Claim
39 words
The shutdown circuit of claims 1 or 2 wherein the low voltage sense means further comprises: restart timer means for deactivating the low voltage sense means for a predetermined time interval following the predetermined interval of said shutdown timer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-07 | 1985-03-09 | 1985-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-07 | 1989-03-09 | 1989-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-07 | 1993-03-09 | 1993-09-08 | $7700.00 | Window Closed / Lapsed |