US3916283A
Expired / Lapsed
US
⏱️ 0.0 years remaining
DC to DC Converter
Assignee: Pylon Electronic Development Co Ltd
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Filing: 1975-02-10
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Granted: 1975-10-28
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Expires: 1995-02-10
Abstract
Abstract Various types of static DC to DC converters are known. Some of these have output rectifiers including phase controlled SCRs. The present invention eliminates the need for controlled output SCRs by pulse width modulation of switching elements in a control circuit controlling the converter circuitry itself. This results in the elimination of some switching devices, higher reliability and higher-efficiency. A unijunction oscillator drives a one-shot multivibrator and a flip flop. The unijunction oscillator, oneshot multivibrator and flip flop feed two AND gates which are alternately enabled to allow pulses of current to flow from a DC source through opposite halves of a primary winding of a transformer. The output of the secondary winding is rectified and filtered to provide the converter output. Voltage regulation is accomplished by controlling the one-shot multivibrator. In one embodiment, paralleling of a number of converters is enabled by providing for frequency and pulse width synchronization.
Inventors
- 👤 John H Burrows
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:12
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: 19
Claim 1
Independent Claim
222 words
A DC to DC converter comprising a control circuit energizable by a source of DC current and having a first pair of output terminals connected in series with said source of DC current and one half of a center-tapped primary winding of a first transformer and a second pair of output terminals connected in series with said source of DC current and the other half of said center-tapped primary winding, said control circuit producing pulses alternately in the two halves of the center-tapped primary winding, said first transformer having a center-tapped secondary winding with each half of said secondary winding being connected to electronic switching means for causing pulses of current to flow said source of DC current alternately in two halves of a center-tapped primary winding of a second transformer, said second transformer having a secondary winding connected to a full wave rectifier having an output connected to an output filter for providing a smooth DC output from the converter, each of said pairs of output terminals being fed by an output transistor fed, in turn, by a driver transistor having an input fed by substantially square wave pulses and across which is connected a capacitor so that the pulses appearing at the output terminals of the control circuit are trapezoidal shaped and thus have substantially no harmonics of radio frequency.
Claim 2
Dependent Claim
222 words
A DC to DC converter comprising a control circuit energizable by a source of DC current and having a first pair of output terminals connected in series with said source of DC current and one half of a center-tapped primary winding of a first transformer and a second pair of output terminals connected in series with said source of DC current and the other half of said center-tapped primary winding, said control circuit producing pulses alternately in the two halves of the center-tapped primary winding, said first transformer having a center-tapped secondary winding with each half of said secondary winding being connected to electronic switching means for causing pulses of current to flow said source of DC current alternately in two halves of a center-tapped primary winding of a second transformer, said second transformer having a secondary winding connected to a full wave rectifier having an output connected to an output filter for providing a smooth DC output from the converter, each of said pairs of output terminals being fed by an output transistor fed, in turn, by a driver transistor having an input fed by substantially square wave pulses and across which is connected a capacitor so that the pulses appearing at the output terminals of the control circuit are trapezoidal shaped and thus have substantially no harmonics of radio frequency.
Claim 3
Dependent Claim
27 words
A DC to DC converter as claimed in claim 1 and further comprising an input filter connected between said source of DC current and said current circuit.
Claim 4
Dependent Claim
17 words
A DC to DC converter as claimed in claim 1 wherein said electronic switching means comprise transistors.
Claim 5
Dependent Claim
154 words
A DC to DC converter as claimed in claim 1 wherein said control circuit comprises a unijunction oscillator driving a flip-flop and a one-shot multivibrator and feeding a first input of each of two three-input AND gates, said flip-flop having one output feeding a second input of one of said AND gates and a second output feeding a second input of the other of said AND gates and said one-shot multivibrator having a pulse output feeding a third input of each of said AND gates, each AND gate being associated with a different one of the pairs of outputs of the control circuit and, when enabled, resulting in current flow from its associated pair of output terminals, said converter further comprising feedback means responsive to current flow in the output of the converter for regulating the pulse duration of the one-shot multivibrator and hence the duration of time that the AND gates are enabled.
Claim 6
Dependent Claim
97 words
A DC to DC converter as claimed in claim 4 wherein the feedback means comprises a resistor in series with the output of the converter and across which leads are connected for deriving a feedback voltage proportional to output current from the converter, said feedback voltage feeding a blocking oscillator which produces an output voltage which is fed to a rectifier and integrator to produce a control voltage proportional to the output current of the converter, said control voltage being fed to control means which, in turn, affects the duration of output pulses from the one-shot multivibrator.
Claim 7
Dependent Claim
152 words
A DC to DC converter as claimed in claim 1 wherein said control circuit comprises a unijunction oscillator driving a flip-flop and a one-shot multivibrator and a feeding a first input of each of two three-input AND gates, said flip-flop having one output feeding a second input of one of said AND gates and a second output feeding a second input of the other of said AND gates and said one-shot multivibrator having a pulse output feeding a third input of each of said AND gates, each AND gate being associated with a different one of the pairs of outputs of the control circuit and, when enabled, resulting in current flow from its associated pair oF output terminals, said converter further comprising feedback means responsive to output voltage of the converter for regulating the pulse duration of the one-shot multivibrator and hence the duration of time that the AND gates are enabled.
Claim 8
Dependent Claim
60 words
A DC to DC converter as claimed in claim 6 wherein the output voltage is fed back to a light emitting diode which produces light proportional to said output voltage, said light being coupled to a light sensitive transistor which produces a current which affects control means which, in turn, affects the duration of output pulses from the one-shot multivibrator.
Claim 9
Dependent Claim
38 words
A DC to DC converter as claimed in claim 7 wherein said light emitting diode is in series with a variable resistor so that the amount of feedback current to the light emitting diode can be manually adjusted.
Claim 10
Dependent Claim
47 words
A DC to DC converter as claimed in claim 5 wherein the integrator comprises a resistor in series with a capacitor and a potentiometer having a movable tap is connected in parallel with the capacitor, the control voltage being derived from the movable tap of the potentiometer.
Claim 11
Dependent Claim
33 words
A DC to DC converter as claimed in claim 4 wherein said unijunction oscillator drives said flip-flop and one-shot multivibrator and feeds the first inputs of the AND gates via a pulse former.
Claim 12
Dependent Claim
33 words
A DC to DC converter as claimed in claim 7 wherein said unijunction oscillator drives said flip-flop and one-shot multivibrator and feeds the first inputs of the AND gates via a pulse former.
Claim 13
Dependent Claim
31 words
A DC to DC converter as claimed in claim 4 wherein each AND gate, when enabled, produces a pulse which feeds an amplifier, which amplifier feeds one of said driver transistors.
Claim 14
Dependent Claim
31 words
A DC to DC converter as claimed in claim 7, wherein each AND gate, when enabled, produces a pulse which feeds an amplifier, which amplifier feeds one of said driver transistors.
Claim 15
Dependent Claim
42 words
A DC to DC converter as claim 1 and including means for directly energizing said control circuit from said source of DC current during startup of the converter and means for indirectly energizing said control circuit during normal operation of the converter.
Claim 16
Dependent Claim
27 words
A DC to DC converter as claimed in claim 14 wherein said means for indirectly energizing said control circuit comprises a tertiary winding on said second transformer.
Claim 17
Dependent Claim
22 words
A DC to DC converter as claimed in claim 15 wherein said tertiary winding provides a lower voltage than said DC source.
Claim 18
Dependent Claim
114 words
A DC to DC converter as claimed in claim 1 and further comprising a threshold responsive circuit having a first and a second input and an output connected to supply electrical energy to the control circuit, said first input being connected to the DC source and said second input being connected to a tertiary winding on said second transformer, said threshold responsive circuit being responsive to a predetermined voltage level on said second input so that when said threshold level is exceeded electrical energy is supplied to the control circuit from said second input whereas when said threshold level is not exceeded electrical energy is supplied to the control circuit from said first input.
Claim 19
Dependent Claim
131 words
A DC to DC converter as claimed in claim 17 wherein said threshold responsive circuit comprises a first and a second transistor each having a collector, a base, and an emitter, said first input being connected to the collector of the first transistor and through a resistor to the base of the second transistor, said second input being connected to the collector of the second transistor, the emitters of the two transistors being connected together and to an electrical energization line of positive polarity for the control circuit, the base of the first transistor being connected through a Zener diode to a negative polarity energization line for the control circuit, and the base of the second transistor being connected through at least one diode to the base of the second transistor.
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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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |