EP0105541A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A DC-to-AC voltage converter having galvanically separated input and output(s)
Assignee: Nederlandsche Apparatenfabriek NEDAP NV
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Filing: 1983-09-01
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Granted: —
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Expires: 2003-09-01
Abstract
Abstract @ A DC-to-AC voltage converter for the supply of power to at least one load, comprising an input circuit and at least one output circuit galvanically separated from said input circuit, and a converter transformer. According to the invention a primary winding of the converter transformer is series-connected to a switching transistor, which series circuit arrangement is connected between a positive input terminal and a negative input terminal, with one or more resonance capacitors being connected in parallel with the collector-emitter circuit of the switching transistor and/or in parallel with said primary winding. Control means are provided for said switching transistor, with the resonance capacitor(s) and said primary winding being dimensioned so that, under all anticipated load conditions of the converter, including short-circuiting of the output circuits, the control means cause the voltage across the collector-emitter circuit of the switching transistor, after the latter has become non-conductive, to fall back to a very low value before the switching transistor is again driven into the conductive state. The converter transformer has a first auxiliary winding strongly coupled with said primary winding and, at least in part, provides the driving power required for the switching transistor. A time-delay and turn-off circuit is energized and synchronized by at least one second auxiliary winding of the converter transformer, and a smoothing circuit provides the driving power for turning off the switching transistor, which driving power is withdrawn from a third auxiliary winding of the converter transformer.
Inventors
- 👤 Gerben Simon Hoeksma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 08:31
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/539; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33507; H02M3/33523
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
255 words
A DC-to-AC voltage converter for the supply of power to at least one load, comprising an input circuit and at least one output circuit galvanically separated from said input circuit, and a converter transformer, characterized in that a primary winding (1) of the converter transformer (2) is series-connected to a switching transistor (3), which series circuit arrangement is connected between a positive input terminal (20) and a negative input terminal (21), with one or more resonance capacitors (4) being connected in parallel with the collector-emitter circuit of the switching transistor and/or in parallel with said primary winding; there being provided control means for said switching transistor, with the resonance capacitor(s) and said primary winding being dimensioned so that, under all anticipated load conditions of the converter, including short-circuiting of the output circuits, the control means cause the voltage across the collector-emitter circuit of the switching transistor, after the latter has become non-conductive, to fall back to a very low value before the switching transistor is again driven into the conductive state; said converter transformer having a first auxiliary winding (7) strongly coupled with said primary winding and, at least in part, providing the driving power required for the switching transistor; there being provided a time-delay and turn-off circuit (13) energized and synchronized t by at least one second auxiliary winding of the converter transformer; there being provided a smoothing circuit (11) providing the driving power for turning off the switching transistor, which driving power is withdrawn from a third auxiliary winding of the converter transformer.
Claim 2
Dependent Claim
255 words
A DC-to-AC voltage converter for the supply of power to at least one load, comprising an input circuit and at least one output circuit galvanically separated from said input circuit, and a converter transformer, characterized in that a primary winding (1) of the converter transformer (2) is series-connected to a switching transistor (3), which series circuit arrangement is connected between a positive input terminal (20) and a negative input terminal (21), with one or more resonance capacitors (4) being connected in parallel with the collector-emitter circuit of the switching transistor and/or in parallel with said primary winding; there being provided control means for said switching transistor, with the resonance capacitor(s) and said primary winding being dimensioned so that, under all anticipated load conditions of the converter, including short-circuiting of the output circuits, the control means cause the voltage across the collector-emitter circuit of the switching transistor, after the latter has become non-conductive, to fall back to a very low value before the switching transistor is again driven into the conductive state; said converter transformer having a first auxiliary winding (7) strongly coupled with said primary winding and, at least in part, providing the driving power required for the switching transistor; there being provided a time-delay and turn-off circuit (13) energized and synchronized t by at least one second auxiliary winding of the converter transformer; there being provided a smoothing circuit (11) providing the driving power for turning off the switching transistor, which driving power is withdrawn from a third auxiliary winding of the converter transformer.
Claim 3
Dependent Claim
23 words
A converter according to claim 1, characterized in that the first and second auxiliary windings are one and the same auxiliary winding (7).
Claim 4
Dependent Claim
25 words
A converter according to claim 1 or 2, characterized in that the first and third auxiliary windings are one and the same auxiliary winding (7).
Claim 5
Dependent Claim
81 words
A converter according to claim 1, 2 or 3, characterized in that a diode (5) is connected anti-parallel to the base-emitter diode of the transistor (3), and that the driving power of the switching transistor (3) is supplied at least in part by charge storage in the base-collector diode of the switching transistor, which driving power adapts itself automatically to the collector end current of the switching transistor to'prevent supersaturation of the transistor in the event of small collector output currents.
Claim 6
Dependent Claim
42 words
A converter according to anyone of the preceding claims, characterized by an adjustment means connected to said time-delay and turn-off circuit (13), and capable of affecting the conduction interval of the switching transistor to control the power supplied to the load(s) (17).
Claim 7
Dependent Claim
44 words
A converter according to claim 5, characterized in that said adjusting means comprises a feedback member (14) connected between the input circuit and the output circuit(s) (17), designed so that the galvanic separation between input and output circuit(s) is maintained in said feedback member.
Claim 8
Dependent Claim
15 words
A converter according to claim 6, characterized in that said feedback member comprises an "octocoupler".
Claim 9
Dependent Claim
57 words
A converter according to claim 5 or 6, characterized by a comparator circuit (15) connected between the output circuit(s) and the feedback member (14), said comparator circuit being arranged to compare the actual value of an output magnitude with a set target value, and to supply an output signal dependent on such comparison to said feedback member.
Claim 10
Dependent Claim
63 words
A converter according to claim 5, characterized in that said adjusting means comprises a comparator circuit (15) coupled with the output circuit(s) while maintaining a galvanic separation, said comparator circuit being arranged to compare the actual value of an output magnitude with a set target value and to supply an output signal dependent on such comparison to said time-delay and turn-off circuit (13).
Claim 11
Dependent Claim
31 words
A converter according to claim 8 or 9, characterized in that the output magnitude is formed by rectifying and smoothing the voltages across the secondary winding(s) (16) of the converter transformer.
Claim 12
Dependent Claim
35 words
A converter according to claim 8 or 9, characterized in that the output magnitude is the light intensity of one or more gas discharge lamps connected to the secondary winding(s) (16) of the converter transformer.
Claim 13
Dependent Claim
53 words
A converter according to anyone of the preceding claims, characterized by a current limiter (19) comprising a comparator circuit, and limiting the collector and current of the switching transistor, and turning off said switching transistor via the time-delay and turn-off circuit (13) upon a pre-determined value of the collector and current being reached.
Claim 14
Dependent Claim
68 words
A converter according to anyone of claims 6 - 8 or 9 - 11, respectively, characterized by a time measuring circuit (48, 50, 53) respectively coupled to said feedback member (14) or to the comparator circuit (15) and arranged to turn off the converter or adjust it to a low value if no feedback signal is received for a pre-determined period after the converter has been turned on.
Claim 15
Dependent Claim
31 words
A converter according to claim 13, characterized in that the time measuring circuit forms part of the time-delay and turn-off circuit (13) and is capable of turning off the switching transistor.
References Cited (Backward Citations)
No citation records indexed.
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