US3818312A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dc-ac converter
Assignee: US Philips Corp
•
Filing: 1972-09-11
•
Granted: 1974-06-18
•
Expires: 1992-09-11
Abstract
Abstract A DC-AC converter includes a transformer with its primary winding in series with a transistor across the terminals of a DC voltage source. A resistor is connected between the emitter and base of the transistor and a coupling capacitor connects a coupling winding of the transformer to the base of the transistor. An auxiliary DC voltage source is included in the connection between the emitter and the resistor so that the converter is less sensitive to variations in the DC source voltage.
Inventors
- 👤 M Luursema
- 👤 H Palmers
- 👤 D Wijsboom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:37
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5383; H02M7/53832; H02M7/53835; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/338; H02M3/3382; H02M3/3384
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
143 words
A dc-ac converter comprising a pair of input terminals adapted for connection to a source of voltage, a resistor, a transistor having an emitter, base and collector, means connecting the transistor emitter through the resistor to its base, a transformer having a primary winding, a coupling winding and a secondary winding, means connecting at least part of the primary winding as a part of the emitter-collector circuit of the transistor arranged across said input terminals of the converter, a coupling capacitor connected between the coupling winding of the transformer and the connection between the resistor and the base of the transistor, an auxiliary direct voltage source included in the connection between the emitter of the transistor and the resistor, said auxiliary direct voltage source having a polarity which tends to make the transistor conduct, and means connecting the secondary winding to a load.
Claim 2
Dependent Claim
143 words
A dc-ac converter comprising a pair of input terminals adapted for connection to a source of voltage, a resistor, a transistor having an emitter, base and collector, means connecting the transistor emitter through the resistor to its base, a transformer having a primary winding, a coupling winding and a secondary winding, means connecting at least part of the primary winding as a part of the emitter-collector circuit of the transistor arranged across said input terminals of the converter, a coupling capacitor connected between the coupling winding of the transformer and the connection between the resistor and the base of the transistor, an auxiliary direct voltage source included in the connection between the emitter of the transistor and the resistor, said auxiliary direct voltage source having a polarity which tends to make the transistor conduct, and means connecting the secondary winding to a load.
Claim 3
Dependent Claim
83 words
A dc-ac converter as claimed in claim 1, wherein the auxiliary direct voltage source comprises a Zener diode connected between the emitter of the transistor and the resistor and a second capacitor connected between the junction of the coupling capacitor and the coupling winding at one end and the junction between the Zener diode and the resistor at the other end so that a voltage in the cut-off direction is realized on the Zener diode via a current flowing through the second capacitor.
Claim 4
Dependent Claim
71 words
A dc-ac converter as claimed in claim 1 wherein the load includes a stabilised electric discharge lamp, an inductor connected in the emitter-collector circuit of the transistor, and the auxiliary direct voltage source comprises a third capacitor which is included in a charge circuit which also includes a second resistor and a diode, and means connecting said charge circuit in a closed circuit with at least a part of the inductor.
Claim 5
Dependent Claim
74 words
A dc-ac converter as claimed in claim 1 further comprising a second transistor connected in a push-pull circuit configuration with the first transistor and the primary winding across said input terminals, a second resistor connected between the emitter and base of the second transistor, and means connecting said auxiliary direct voltage source between the emitter of the second transistor and the second resistor with a polarity that tends to make the second transistor conduct.
Claim 6
Dependent Claim
94 words
A dc-ac converter as claimed in claim 4 further comprising a second coupling capacitor connected between the coupling winding and the connection between the second resistor and the base of the second transistor, and wherein said auxiliary direct voltage source comprises, first and second zener diodes connected between the emitter electrodes of said first and second transistors and said first and second resistors, respectively, and third and fourth capacitors connected between their respective junctions of the coupling capacitor and the coupling winding and the junctions between the respective zener diodes and their respective resistors.
Claim 7
Dependent Claim
63 words
A dc-ac converter as claimed in claim 4 further comprising an inductor connected in series with the emitter-collector paths of said first and second transistors across said input terminals, and wherein said auxiliary direct voltage source comprises, a diode, a third resistor and a second capacitor serially connected across at least a part of the inductor to form a closed loop circuit therewith.
Claim 8
Dependent Claim
131 words
A dc-ac converter comprising a pair of input terminals adapted to be connected to a source of DC voltage, a transistor, a transformer having a primary winding, a coupling winding and a secondary winding, means connecting at least a part of said primary winding in series with the transistor across said input terminals, a coupling capacitor connected between said coupling winding and the base of the transistor, a resistor connected between the emitter and base of the transistor so as to lie outside of the main DC current path of the transistor, an auxiliary DC voltage source connectEd in series with the resistor between the emitter and base of the transistor and with a polarity that tends to make the transistor conduct, and means connecting the secondary winding to a load.
Claim 9
Dependent Claim
131 words
A dc-ac converter comprising a pair of input terminals adapted to be connected to a source of DC voltage, a transistor, a transformer having a primary winding, a coupling winding and a secondary winding, means connecting at least a part of said primary winding in series with the transistor across said input terminals, a coupling capacitor connected between said coupling winding and the base of the transistor, a resistor connected between the emitter and base of the transistor so as to lie outside of the main DC current path of the transistor, an auxiliary DC voltage source connectEd in series with the resistor between the emitter and base of the transistor and with a polarity that tends to make the transistor conduct, and means connecting the secondary winding to a load.
Claim 10
Dependent Claim
37 words
A dc-ac converter as claimed in claim 7 further comprising a first capacitor connected in shunt with the series arrangement of the resistor and auxiliary DC voltage source across the emitter and base electrodes of the transistor.
Claim 11
Dependent Claim
43 words
A dc-ac converter as claimed in claim 7 wherein the auxiliary DC voltage source includes a constant voltage reference element in series with said resistor and a capacitor connected between the coupling winding and the junction between the reference element and the resistor.
Claim 12
Dependent Claim
64 words
A dc-ac converter as claimed in claim 7 further comprising an inductor connected in series with the transistor across said input terminals, and wherein said auxiliary DC voltage source comprises, a diode, a second resistor, a capacitor, and means serially connecting said diode, said second resistor and said capacitor across at least a part of the inductor to form a closed loop circuit therewith.
Claim 13
Dependent Claim
79 words
A dc-ac converter as claimed in claim 7 further comprising a second transistor connected in a push-pull circuit configuration with the first transistor and the primary winding across said input terminals, a second resistor connected between the emitter and base of the second transistor, and means connecting said auxiliary direct voltage source in series with the second resistor between the emitter and base of the second transistor and with a polarity that tends to make the second transistor conduct.
Claim 14
Dependent Claim
86 words
A dc-ac converter as claimed in claim 11 further comprising a first capacitor connected between the base and emitter of the first transistor and in series with the coupling capacitor between said coupling winding and said emitter, a second coupling capacitor connected between the coupling winding and the base of the second transistor, and a second capacitor connected between the base and emitter of the second transistor and in series with the second coupling capacitor between said coupling winding and said emitter of the second transistor.
Claim 15
Dependent Claim
67 words
A dc-ac converter as claimed in claim 11 further comprising an inductor connected in series with said first and second transistors across said input terminals, and wherein said auxiliary DC voltage source comprises, a diode, a third resistor, a capacitor, and means serially connecting said diode, said third resistor and said capacitor across at least a part of the inductor to form a closed loop circuit therewith.
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |