Patent US4253137A successfully refreshed from Google Patents.
US4253137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switched-mode power supply
Assignee: US Philips Corp
•
Filing: 1978-02-28
•
Granted: 1981-02-24
•
Expires: 1998-02-28
Abstract
Abstract A switched-mode power supply with mains isolation comprising a primary circuit with a switch, a first secondary circuit working simultaneously with the switch and which generates a non-regulated voltage and a second, non-simultaneous, secondary circuit which forms part of a flyback converter. The sum of the two generated voltages is regulated.
Inventors
- 👤 Neti R. M. Rao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:07
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33538; H02M3/33546
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
240 words
A switched-mode power supply circuit for converting an input D.C. voltage into an output D.C. voltage which is substantially independent of variations in the input voltage and to which output voltage a load is connected, the circuit comprising, a pair of input terminals for connection to a source of said input voltage, a transformer having a primary winding and secondary winding means, means connecting the series arrangement of said primary winding of the transformer and a controlled switch to the input terminals, means responsive to the output voltage for controlling the switch operation so that the switch is periodically brought alternately into the conducting and the cut-off states with the duration of the conducting state of the switch being adjustable as a function of the output voltage, a first rectifier connected to the secondary winding means of the tranformer with its polarity chosen in relation to the winding sense of the secondary winding means such that the rectifier conducts during the cut-off period of the switch, a second rectifier connected to the secondary winding means of the transformer with its polarity chosen in relation to the winding sense of said secondary winding means such that the second rectifier conducts during the conduction period of the switch, and means coupling the load to the first and second rectifiers so that the output D.C. voltage is the sum of first and second D.C. voltages derived from the first and second rectifiers, respectively.
Claim 2
Dependent Claim
240 words
A switched-mode power supply circuit for converting an input D.C. voltage into an output D.C. voltage which is substantially independent of variations in the input voltage and to which output voltage a load is connected, the circuit comprising, a pair of input terminals for connection to a source of said input voltage, a transformer having a primary winding and secondary winding means, means connecting the series arrangement of said primary winding of the transformer and a controlled switch to the input terminals, means responsive to the output voltage for controlling the switch operation so that the switch is periodically brought alternately into the conducting and the cut-off states with the duration of the conducting state of the switch being adjustable as a function of the output voltage, a first rectifier connected to the secondary winding means of the tranformer with its polarity chosen in relation to the winding sense of the secondary winding means such that the rectifier conducts during the cut-off period of the switch, a second rectifier connected to the secondary winding means of the transformer with its polarity chosen in relation to the winding sense of said secondary winding means such that the second rectifier conducts during the conduction period of the switch, and means coupling the load to the first and second rectifiers so that the output D.C. voltage is the sum of first and second D.C. voltages derived from the first and second rectifiers, respectively.
Claim 3
Dependent Claim
38 words
A circuit as claimed in claim 1 further comprising a first capacitor coupled to the first rectifier for smoothing the first D.C. voltage and a second capacitor coupled to the second rectifier for smoothing the second D.C. voltage.
Claim 4
Dependent Claim
45 words
A circuit as claimed in claim 1 further comprising a first capacitor coupled to one of said first and second rectifiers for smoothing the D.C. voltage derived thereby, and a second capacitor connected directly in parallel with the load for smoothing the output D.C. voltage.
Claim 5
Dependent Claim
40 words
A circuit as claimed in claims 2 or 3, wherein the transformer secondary winding means includes first and second secondary windings with the first rectifier connected to the first secondary winding and the second rectifier to the second secondary winding.
Claim 6
Dependent Claim
19 words
A circuit as claimed in claim 4, wherein said first and second secondary windings have a common winding section.
Claim 7
Dependent Claim
27 words
A circuit as claimed in claims 2 or 3, further comprising means directly connecting one terminal of the first capacitor to one terminal of the second capacitor.
Claim 8
Dependent Claim
25 words
A circuit as claimed in claim 6 further comprising means connecting the load between the other terminals of the first capacitor and the second capacitor.
Claim 9
Dependent Claim
24 words
A circuit as claimed in claims 1 or 2 or 3 and further comprising an impedance element connected in series with the second rectifier.
Claim 10
Dependent Claim
14 words
A circuit as claimed in claim 8, wherein the impedance element comprises an inductor.
Claim 11
Dependent Claim
24 words
A circuit as claimed in claim 9 further comprising a third diode connected to a junction formed between the second rectifier and the inductor.
Claim 12
Dependent Claim
53 words
A circuit as claimed in claim 1 further comprising a first capacitor coupled to one of said first and second rectifiers for smoothing the D.C. voltage derived therefrom and a second capacitor coupled to the other one of said first and second rectifiers and to the load for smoothing the output D.C. voltage.
Claim 13
Dependent Claim
77 words
A power supply circuit as claimed in claim 1 further comprising a first capacitor coupled to the first rectifier to derive a first D.C. voltage across said first capacitor that is determined by the duration of the conducting state of the controlled switch and a second capacitor coupled to the second rectifier to derive a second D.C. voltage across said second capacitor that is substantially independent of the duration of the conducting state of the controlled switch.
Claim 14
Dependent Claim
87 words
A power supply circuit as claimed in claim 1 wherein the transformer secondary winding means includes first and second secondary windings and further comprising a first capacitor connected in series with said first rectifier between one terminal of the first secondary winding and a point of reference potential and a second capacitor connected in series with said second rectifier between one terminal of the second secondary winding and said point of reference potential, and said load coupling means couples the load in parallel with the second capacitor.
Claim 15
Dependent Claim
55 words
A power supply circuit as claimed in claim 1 wherein the transformer secondary winding means comprises first and second secondary windings coupled to the first and second rectifiers, respectively, and said load coupling means connects said first and second rectifiers and at least one of said secondary windings in series circuit across the load terminals.
Claim 16
Dependent Claim
76 words
A power supply circuit as claimed in claim 1 further comprising first and second capacitors, and wherein the transformer secondary winding means comprises a secondary winding having a tap point connected to a first terminal of the load via the second rectifier and first and second terminals connected to a second terminal of the load via the first rectifier and the first capacitor, respectively, and wherein the second capacitor is connected in parallel with the load.
Claim 17
Dependent Claim
86 words
A power supply circuit as claimed in claim 1 further comprising first and second capacitors, and wheren the transformer secondary winding means comprises a secondary winding having a tap point connected to a first terminal of the load via the second rectifier and first and second terminals connected to a second terminal of the load via the first rectifier and the first capacitor, respectively, and wherein the second capacitor is connected in series with the first capacitor across the first and second terminals of the load.
Claim 18
Dependent Claim
228 words
A switching voltage regulator circuit comprising, a pair of input terminals for connection to a source of input voltage, an output terminal for supplying a D.C. output voltage to a load, a transformer having a primary winding and secondary winding means, controlled switching means having a control electrode, means connecting the transformer primary winding in series circuit with said switching means across the input terminals, first and second rectifiers coupling the secondary winding means to the output terminal with said rectifiers polarized relative to the winding sense of the secondary winding means so that the first rectifier conducts during the cut-off period of the switching means and the second rectifier conducts during the conduction period of the switching means, the output terminal being coupled to the first and second rectifiers so that the output D.C. voltage is the sum of first and second D.C. voltages derived by the first and second rectifiers, respectively, and control means responsive to the output voltage and coupled to the switching means control electrode for alternately driving the switching means into conduction and cut-off with a duty cycle that varies as a function of the output voltage such that the first and second D.C. voltages derived by the first and second rectifiers compensate each other whereby the D.C. output voltage at the output terminal is substantially independent of variations in the input voltage.
Claim 19
Dependent Claim
228 words
A switching voltage regulator circuit comprising, a pair of input terminals for connection to a source of input voltage, an output terminal for supplying a D.C. output voltage to a load, a transformer having a primary winding and secondary winding means, controlled switching means having a control electrode, means connecting the transformer primary winding in series circuit with said switching means across the input terminals, first and second rectifiers coupling the secondary winding means to the output terminal with said rectifiers polarized relative to the winding sense of the secondary winding means so that the first rectifier conducts during the cut-off period of the switching means and the second rectifier conducts during the conduction period of the switching means, the output terminal being coupled to the first and second rectifiers so that the output D.C. voltage is the sum of first and second D.C. voltages derived by the first and second rectifiers, respectively, and control means responsive to the output voltage and coupled to the switching means control electrode for alternately driving the switching means into conduction and cut-off with a duty cycle that varies as a function of the output voltage such that the first and second D.C. voltages derived by the first and second rectifiers compensate each other whereby the D.C. output voltage at the output terminal is substantially independent of variations in the input voltage.
Claim 20
Dependent Claim
36 words
A switching voltage regulator circuit as claimed in claim 17 further comprising first and second filter capacitors coupled to said first and second rectifiers, respectively, across which capacitors said first and second D.C. voltages are developed.
Claim 21
Dependent Claim
31 words
A switching voltage regulator circuit as claimed in claim 18 wherein said control means includes an oscillator and a pulse width modulator which controls the duty cycle of the switching means.
Claim 22
Dependent Claim
50 words
A switching voltage regulator circuit as claimed in claim 17 further comprising a first filter capacitor coupled to one of said rectifiers for smoothing the D.C. voltage derived by said one rectifier and a second filter capacitor coupled to the output terminal so as to smooth the output D.C. voltage.
Claim 23
Dependent Claim
30 words
A switching voltage regulator circuit as claimed in claim 20 wherein the transformer secondary winding means includes first and second secondary windings coupled to the first and second rectifiers, respectively.
Claim 24
Dependent Claim
72 words
A switching voltage regulator circuit as claimed in claims 17 or 18 wherein the transformer includes a magnetic core and further comprising an inductor connected in series with the second rectifier so as to limit the current flow in said switching means, said inductor having a low inductance value that is independent of the level of magnetic flux in the core of the transformer during the conduction period of the switching means.
Claim 25
Dependent Claim
61 words
A switching voltage regulator circuit as claimed in claim 18 wherein the transformer secondary winding means comprises first and second secondary windings coupled to the first and second rectifiers, respectively, the first and second transformer secondary windings having a different number of turns chosen so that said first and second D.C. voltages developed across the first and second capacitors are unequal.
Claim 26
Dependent Claim
71 words
A voltage regulator circuit as claimed in claim 17 further comprising a first capacitor coupled to the first rectifier to derive a first D.C. voltage across said first capacitor that is determined by the duty cycle of the switching means, and a second capacitor coupled to the second rectifier to derive a second D.C. voltage across said second capacitor that is substantially independent of the duty cycle of the switching means.
Claim 27
Dependent Claim
45 words
A switching voltage regulator circuit as claimed in claim 17 wherein the transformer secondary winding means comprises first and second secondary windings coupled to the first and second rectifiers, respectively, and with the second winding having a greater number of turns than the first winding.
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) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |