US3859583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse-width modulation converter circuit providing asymmetry correction and current monitoring
Assignee: AT&T Inc
•
Filing: 1973-10-23
•
Granted: 1975-01-07
•
Expires: 1993-10-23
Abstract
Abstract A dc-to-dc voltage converter circuit regulated by pulse-width modulation techniques in which correction circuitry is provided to maintain balanced conduction in the converter switching transistors. The correction circuitry monitors the conduction of each transistor by means of a sensing transformer in a circuit common to the emitters of both transistors and an imbalance signal is derived when the emitter currents are unequal in amplitude. The imbalance signal in conjunction with one or the other transistor control signals adjusts the transistor drive circuits in turn to adjust the transistor duty cycles to obtain the required conduction symmetry. The same imbalance signal is employed in comparison with predetermined signal levels to monitor various circuit current levels for circuit protection.
Inventors
- 👤 Ray Allen Reed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:10
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/337; H02M3/3376; H02M3/3378
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
330 words
A voltage converter circuit comprising a converter stage comprising a first and a second transistor, an output transformer having a primary winding connected at opposite ends to respective corresponding first electrodes of said transistors and having a secondary winding, and a common circuit for respective corresponding second electrodes of said transistors connected at one end to a center-tap of said primary winding, said common circuit being adapted for including a source of voltage; a pulse width modulator stage comprising drive means for alternately applying a first and a second control pulse to corresponding control electrodes of said transistors for controlling conducting time durations of said transistors, said transistors alternately generating first and second output signals in said common circuit; first means for individually and selectively controlling said conducting time durations comprising a sensing transformer coupled in said common circuit for generating a first and a second current level indicator signal responsive to said first and second output signals, respectively, means for generating an imbalance signal when one of said current level indicator signals is greater in magnitude than the other of said current level indicator signals, and first control circuit means responsive to said first and second pulses and said imbalance signal for controlling said drive means to individually alter the time duration of said first and second control pulses and thereby the magnitudes of said first and second output signals in said common circuit; and second means for simultaneously controlling said conducting time durations comprising an output circuit stage connected to said secondary winding, second control circuit means including a comparator circuit responsive to signals of a predetermined magnitude for controlling said drive means to simultaneously alter the time duration of said first and second control pulses and thereby the magnitudes of said first and second output signals in said common circuit, and feedback circuit means connected to said output circuit stage for applying a portion of signals appearing in said output circuit to said second control circuit means.
Claim 2
Dependent Claim
330 words
A voltage converter circuit comprising a converter stage comprising a first and a second transistor, an output transformer having a primary winding connected at opposite ends to respective corresponding first electrodes of said transistors and having a secondary winding, and a common circuit for respective corresponding second electrodes of said transistors connected at one end to a center-tap of said primary winding, said common circuit being adapted for including a source of voltage; a pulse width modulator stage comprising drive means for alternately applying a first and a second control pulse to corresponding control electrodes of said transistors for controlling conducting time durations of said transistors, said transistors alternately generating first and second output signals in said common circuit; first means for individually and selectively controlling said conducting time durations comprising a sensing transformer coupled in said common circuit for generating a first and a second current level indicator signal responsive to said first and second output signals, respectively, means for generating an imbalance signal when one of said current level indicator signals is greater in magnitude than the other of said current level indicator signals, and first control circuit means responsive to said first and second pulses and said imbalance signal for controlling said drive means to individually alter the time duration of said first and second control pulses and thereby the magnitudes of said first and second output signals in said common circuit; and second means for simultaneously controlling said conducting time durations comprising an output circuit stage connected to said secondary winding, second control circuit means including a comparator circuit responsive to signals of a predetermined magnitude for controlling said drive means to simultaneously alter the time duration of said first and second control pulses and thereby the magnitudes of said first and second output signals in said common circuit, and feedback circuit means connected to said output circuit stage for applying a portion of signals appearing in said output circuit to said second control circuit means.
Claim 3
Dependent Claim
79 words
A voltage converter circuit as claimed in claim 1 also comprising a first monitoring circuit for monitoring the output current level of said converter circuit comprising means operated responsive to said first and second current level indicator signals for comparing the magnitude of said last-mentioned signals with a first predetermined signal magnitude and means for generating a first turn-off signal when said first and second current level indicator signals are greater in magnitude than said first predetermined signal magnitude.
Claim 4
Dependent Claim
96 words
A voltage converter circuit as claimed in Claim 2 also comprising a second monitoring circuit for monitoring the input current level of said converter circuit comprising means operated responsive to said first and second current level indicator signals for generating a first average signal representing the average magnitude of said first and second current level indicator signals, means for comparing the magnitude of said first average signal with a second predetermined signal magnitude, and means for generating a second turn-off signal when said first average signal is greater in magnitude than said second predetermined signal magnitude.
Claim 5
Dependent Claim
103 words
A voltage converter circuit as claimed in claim 3 also comprising a third monitoring circuit for monitoring current changes in said converter circuit comprising means operated responsive to said first and second current level indicator signals for generating a second average signal representing the average magnitude of said first and second current level indicator signals, means for lowering the reference level of said second average signal, means for comparing the amplitudes of said first and second average signals, and means for generating a third turn-off signal when the amplitude of said second average signal rises above the amplitude of said first average signal.
Claim 6
Dependent Claim
31 words
A voltage converter circuit as claimed in claim 4 also comprising circuit means operated responsive to any one of said first, second, and third turn-off signals for deactivating said drive means.
Claim 7
Dependent Claim
239 words
In a dc-to-dc voltage converter circuit, in combination, a pulse-width modulation stage comprising a first and a second conducting element, a common output circuit path for said conducting elements, a first and a second drive circuit means for alternately generating first and second drive signals for alternately causing said first and second conducting elements to generate first and second alternating output signals for predetermined time durations in said common output circuit path, and first control circuit means operated responsive to a variation of both said first and second output signals from a predetermined signal level for controlling said first and second drive circuit means to adjust said time durations of said first and second output signals in the same direction; and an output signal symmetry monitoring stage comprising a transformer connected in said common circuit path for tapping first and second monitoring signals representative, respectively, of said first and second output signals, circuit means responsive to the monitoring signal of greater amplitude when said first and second monitoring signals differ in amplitude for generating a first symmetry control signal, circuit means for combining said first symmetry control signal and said first and second drive signals for generating a second symmetry control signal, and second control circuit means operated responsive to said second symmetry control signal for controlling said first and second drive circuit means to adjust said time durations of said first and second output signals in opposite directions.
Claim 8
Dependent Claim
239 words
In a dc-to-dc voltage converter circuit, in combination, a pulse-width modulation stage comprising a first and a second conducting element, a common output circuit path for said conducting elements, a first and a second drive circuit means for alternately generating first and second drive signals for alternately causing said first and second conducting elements to generate first and second alternating output signals for predetermined time durations in said common output circuit path, and first control circuit means operated responsive to a variation of both said first and second output signals from a predetermined signal level for controlling said first and second drive circuit means to adjust said time durations of said first and second output signals in the same direction; and an output signal symmetry monitoring stage comprising a transformer connected in said common circuit path for tapping first and second monitoring signals representative, respectively, of said first and second output signals, circuit means responsive to the monitoring signal of greater amplitude when said first and second monitoring signals differ in amplitude for generating a first symmetry control signal, circuit means for combining said first symmetry control signal and said first and second drive signals for generating a second symmetry control signal, and second control circuit means operated responsive to said second symmetry control signal for controlling said first and second drive circuit means to adjust said time durations of said first and second output signals in opposite directions.
Claim 9
Dependent Claim
61 words
In a dc-to-dc voltage converter circuit, the combination according to claim 6 also comprising a current level monitoring stage comprising circuit means for comparing the amplitudes of said first and second monitoring signals with a first predetermined signal amplitude for generating a first turn-off signal when the amplitudes of said first and second monitoring signals exceed said first predetermined signal amplitude.
Claim 10
Dependent Claim
75 words
In a dc-to-dc voltage converter circuit, the combination according to claim 7, said current level monitoring stage also comprising circuit means for averaging the amplitudes of said first and second monitoring signals for generating a first average amplitude signal and circuit means for comparing said average amplitude signal with a second predetermined signal amplitude for generating a second turn-off signal when the amplitude of said first average amplitude signal exceeds said second predetermined signal amplitude.
Claim 11
Dependent Claim
96 words
IN a dc-to-dc voltage converter circuit, the combination according to claim 8, said current level monitoring stage also comprising circuit means for again averaging the amplitudes of said first and second monitoring signals for generating a second average amplitude signal and circuit means for reducing the reference level of said second average amplitude signal and for comparing said second average amplitude signal with said first average amplitude signal for generating a third turn-off signal when the amplitude of said second average amplitude signal of reduced reference level exceeds the amplitude of said first average amplitude signal.
Claim 12
Dependent Claim
44 words
In a dc-to-dc voltage converter circuit, the combination according to claim 9, said current level monitoring stage also comprising circuit means responsive to any one or more of said first, second, and third turn-off signals for deactivating said first and second drive circuit means.
Claim 13
Dependent Claim
165 words
Symmetry correction circuitry for balancing signals in a first and a second switching device in a pulse-width modulated dc-to-dc converter comprising drive circuit means for alternately applying a control potential to control terminals of said switching devices for predetermined time durations for controlling said switching devices to generate a first and a second output signal and monitoring means for monitoring said output signals comprising a sensing transformer coupled in a common output circuit path of said switching devices, circuit means operated responsive to an amplitude difference in signals appearing in said sensing transformer for generating a difference potential, AND gate means for combining said difference potential with the control potential appearing on the control terminal of one of said switching devices for generating a symmetry correction signal, and correction circuit means responsive to said symmetry correction signal for controlling said drive circuit means for increasing and decreasing said predetermined time durations of the control potentials applied, respectively, to said control terminals of said switching devices.
Claim 14
Dependent Claim
165 words
Symmetry correction circuitry for balancing signals in a first and a second switching device in a pulse-width modulated dc-to-dc converter comprising drive circuit means for alternately applying a control potential to control terminals of said switching devices for predetermined time durations for controlling said switching devices to generate a first and a second output signal and monitoring means for monitoring said output signals comprising a sensing transformer coupled in a common output circuit path of said switching devices, circuit means operated responsive to an amplitude difference in signals appearing in said sensing transformer for generating a difference potential, AND gate means for combining said difference potential with the control potential appearing on the control terminal of one of said switching devices for generating a symmetry correction signal, and correction circuit means responsive to said symmetry correction signal for controlling said drive circuit means for increasing and decreasing said predetermined time durations of the control potentials applied, respectively, to said control terminals of said switching devices.
Claim 15
Dependent Claim
114 words
Symmetry correction circuitry as claimed in claim 11 in which said drive circuit means comprises a pair of differential amplifiers each having a first and a second input, a signal generator for applying to said first inputs of both said amplifiers a potential having a substantially sawtooth waveform, and a potential source for individually applying to said second inputs of each of said amplifiers a potential of a first and second magnitude, respectively, one of said amplifiers generating a first of said control potentials when said sawtooth potential falls below said first potential, the other of said amplifiers generating a second of said control potentials when said sawtooth potential rises above said second potential.
Claim 16
Dependent Claim
40 words
Symmetry correction circuitry as claimed in claim 12 in which said correction circuit means comprises circuit means operated responsive to said symmetry correction signal for simultaneously and correspondingly altering the magnitudes of said potentials of said first and second magnitudes.
References Cited (Backward Citations)
US3439251A
Cited
US3657631A
Cited
US3648150A
Cited
US3697855A
Cited
US3710229A
Cited
US3737756A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |