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US3753155A
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Apparatus for center-referenced pulse width modulation
Assignee: POWER CONTROL CORP
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Filing: 1972-01-21
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Granted: 1973-08-14
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Expires: 1992-01-21
Abstract
Abstract Center-referenced pulse width modulation is accomplished by turning on a bistable element when an initial step sweep signal reaches a voltage reference level during the ON period of an applied gating pulse and turning the bistable element OFF during the OFF period of the gating pulse after a time interval complementary to the ON period of the bistable element preceding the gating pulse center.
Inventors
- 👤 K Opal
- 👤 C Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:03
CPC Classifications
H; H03; H03K; H03K7/00; H03K7/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
120 words
In a pulse width modulation system, means for providing a series of gating pulses of predetermined frequency, means for producing a first signal pulse at a time after the start of a gating pulse inversely related to a reference voltage, means for producing a second signal pulse at a time after termination of the gating pulse substantially equal to the time between the occurrence of the first signal pulse and the termination of the gating pulse, and means responsive to said signal pulses for starting an output pulse upon occurrence of a first signal pulse and terminating the output pulse upon occurrence of a second signal pulse, whereby the width of the output pulses is proportional to said reference voltage.
Claim 2
Dependent Claim
120 words
In a pulse width modulation system, means for providing a series of gating pulses of predetermined frequency, means for producing a first signal pulse at a time after the start of a gating pulse inversely related to a reference voltage, means for producing a second signal pulse at a time after termination of the gating pulse substantially equal to the time between the occurrence of the first signal pulse and the termination of the gating pulse, and means responsive to said signal pulses for starting an output pulse upon occurrence of a first signal pulse and terminating the output pulse upon occurrence of a second signal pulse, whereby the width of the output pulses is proportional to said reference voltage.
Claim 3
Dependent Claim
40 words
The system of claim 1 in which the means responsive to the signal pulses is a bistable element adapted to be turned ON by application of the first signal pulse and turned OFF by application of the second signal pulse.
Claim 4
Dependent Claim
49 words
The system of claim 1 including means for producing a timing signal in response to the start of a gating pulse, the duration of said timing signal being inversely proportional to the reference voltage, and means operative upon completion of the timing signal for pRoducing said first signal pulse.
Claim 5
Dependent Claim
54 words
The system of claim 3 in which said timing signal means includes means for setting an initial voltage level proportional to said reference voltage, means for applying a linearly rising signal to said initial level, and means for producing said first signal pulse when said linearly rising signal equals a constant maximum voltage level.
Claim 6
Dependent Claim
59 words
The system of claim 1 including means responsive to termination of a gating pulse for producing a timing signal, the duration of said timing signal being substantially equal to the duration of the output pulse from its start until termination of the gating pulse, and means operative upon completion of said timing signal for producing said second signal pulse.
Claim 7
Dependent Claim
70 words
The system of claim 5 in which said timing signal means includes a capacitor, means for charging said capacitor at a uniform rate during the period from the start of the output pulse until the termination of the gating pulse, means for thereafter discharging the capacitor at substantially the same rate, and means for producing said second signal pulse when the voltage of the capacitor falls to its initial value.
Claim 8
Dependent Claim
104 words
In a pulse width modulation system, means for providing a series of gating pulses, each of said pulses having a predetermined duration between the start and termination of the pulse, means for producing first and second signal pulses at substantially equal times before and after the termination of each gating pulse, means responsive to said signal pulses for starting an output pulse upon occurrence of the first signal pulse and terminating the output pulse upon occurrence of the second signal pulse, means for supplying a reference voltage and timing means for controlling the duration of said equal times in proportion to said reference voltage.
Claim 9
Dependent Claim
104 words
In a pulse width modulation system, means for providing a series of gating pulses, each of said pulses having a predetermined duration between the start and termination of the pulse, means for producing first and second signal pulses at substantially equal times before and after the termination of each gating pulse, means responsive to said signal pulses for starting an output pulse upon occurrence of the first signal pulse and terminating the output pulse upon occurrence of the second signal pulse, means for supplying a reference voltage and timing means for controlling the duration of said equal times in proportion to said reference voltage.
Claim 10
Dependent Claim
76 words
The system of claim 7 in which said timing means includes means for producing a first signal pulse at a time after the start of a gating pulse inversely proportional to the reference voltage, and means for measuring the time period between the occurrence of the first signal pulse and the termination of the gating pulse and for producing a second signal pulse at the end of an equal time after termination of the gating pulse.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |