US4097773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switched mode power supply
Assignee: Individual
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Filing: 1976-11-01
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Granted: 1978-06-27
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Expires: 1996-11-01
Abstract
Abstract A switched mode power supply includes a pair of capacitors serially connected across a supply input and a pair of switching transistors serially connected across the supply input. The output load circuit is connected between the junction of the capacitors and the junction of the transistors by way of a series conductor. A capacitor is connected in parallel with the load and a further capacitor, which may consitute stray capacitance, is also connected between the junctions of the transistors and the junctions of the capacitors.
Inventors
- 👤 Magnus Carl Wilhelm Lindmark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:07
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
172 words
In a switched mode power supply having a pair of supply voltage terminals, a pair of transistors having their emitter-collector paths connected in series to said terminals, first and second capacitors connected in series between said terminals, a series circuit of a load circuit and an inductor connected between the junction of said first and second capacitors and the junction of said emitter-collector paths, and a source of control pulses connected to the basis of said transistors; the improvement wherein said source of control pulses is connected to render said transistors conductive on alternate pulses, and further comprising a third capacitor connected in parallel with said load circuit and forming a series resonant circuit in combination with said inductor at a frequency substantially equal to the pulse repetition frequency of said control pulses of said source of pulses, whereby back e.m.f. of said inductor at the time of switching off of each of said transistors reduces the emitter-collector voltage of the other transistor at the switch on time of said other transistor.
Claim 2
Dependent Claim
172 words
In a switched mode power supply having a pair of supply voltage terminals, a pair of transistors having their emitter-collector paths connected in series to said terminals, first and second capacitors connected in series between said terminals, a series circuit of a load circuit and an inductor connected between the junction of said first and second capacitors and the junction of said emitter-collector paths, and a source of control pulses connected to the basis of said transistors; the improvement wherein said source of control pulses is connected to render said transistors conductive on alternate pulses, and further comprising a third capacitor connected in parallel with said load circuit and forming a series resonant circuit in combination with said inductor at a frequency substantially equal to the pulse repetition frequency of said control pulses of said source of pulses, whereby back e.m.f. of said inductor at the time of switching off of each of said transistors reduces the emitter-collector voltage of the other transistor at the switch on time of said other transistor.
Claim 3
Dependent Claim
27 words
The switched mode power supply of claim 1 further comprising a fourth capacitor connected in parallel with said series circuit of said load circuit and said inductor.
Claim 4
Dependent Claim
24 words
The switched mode power supply of claim 2 wherein said fourth capacitor comprises the stray capacitance of said series connected inductor and load circuit.
Claim 5
Dependent Claim
26 words
The switched mode power supply of claim 1 further comprising a separate fly-wheel diode connected in parallel with the emitter-collector paths of each of said transistors.
Claim 6
Dependent Claim
24 words
The switched mode power supply of claim 1 further comprising means responsive to a voltage at said load circuit for controlling said control pulses.
Claim 7
Dependent Claim
48 words
The switched mode power supply of claim 5 wherein said means responsive to said output circuit voltage comprises means for simultaneously controlling the frequency of said control pulses and the pulse width of said control pulses, whereby residual current caused by base charges of said transistors is compensated.
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) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |