EP0059053A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Switched mode power supply
Assignee: EMI Group Ltd
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Filing: 1982-02-15
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Granted: —
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Expires: 2002-02-15
Abstract
Abstract Switched mode power supplies have been disclosed for powering discharge lamps and other loads. In one example the line current is shaped, in response to a signal representing the load, or optionally the input, current to provide a suitably high power factor. The circuit, however, includes a switch breaking the input path which is found to be disadvantageous. The invention provides a switching means (CT1) connected across the circuit to control the current without breaking the current path. A current sensing resistor (R1) in the input path senses the current and a potentiometer (6) senses the potential from the rectifier (1). These are compared in a comparator with hysteresis (7) the output of which controls the switching means (VT1). An FET (FET1) connected across part of potentiometer (6) varies the attenuation ratio thereof to maintain the output voltage constant.
Inventors
- 👤 Stephen Paul Webster
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 18:14
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/42; H02M1/4208; H02M1/4225; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/1563; H05; H05B; H05B41/00; H05B41/14; H05B41/26; H05B41/28; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
141 words
A switch mode power supply operative on input unidirectional current derived by a full-wave rectifier from an alternating supply to provide an output unidirectional current to a D.C. load, the power supply including switching means; control means controlling the switching means to render it successively conductive and non-conductive to maintain the instantaneous magnitude of the unidirectional current within a predetermined range of the instantaneous magnitude of a reference signal which is a predetermined function of at least the alternating supply characterised in that the unidirectional current is supplied to a capacitance connected across the output of the supply via a series arrangement of an inductor and a device which is rendered conductive alternately with the switching means, the switching means being connected across the device and the capacitance to control the current supplied to the load without breaking the current path.
Claim 2
Dependent Claim
141 words
A switch mode power supply operative on input unidirectional current derived by a full-wave rectifier from an alternating supply to provide an output unidirectional current to a D.C. load, the power supply including switching means; control means controlling the switching means to render it successively conductive and non-conductive to maintain the instantaneous magnitude of the unidirectional current within a predetermined range of the instantaneous magnitude of a reference signal which is a predetermined function of at least the alternating supply characterised in that the unidirectional current is supplied to a capacitance connected across the output of the supply via a series arrangement of an inductor and a device which is rendered conductive alternately with the switching means, the switching means being connected across the device and the capacitance to control the current supplied to the load without breaking the current path.
Claim 3
Dependent Claim
32 words
A power supply according to Claim 1 in which the reference signal is compared with the unidirectional current supplied by the full wave rectifier to maintain a power factor substantially at unity.
Claim 4
Dependent Claim
47 words
A power supply according to either Claim 1 or Claim 2 in which means are provided to sense the magnitude of the unidirectional voltage at the output and to vary the reference signal to maintain the output voltage substantially constant irrespective of variation in the alternating supply.
Claim 5
Dependent Claim
90 words
A switched mode power supply, operative on unidirectional current derived by a full wave rectifier from an alternating supply, to provide a unidirectional output current to a load, the power supply including a converter circuit and control means responsive to the load or input current to generate a reference signal to control the converter circuit so that the phase difference between the input current and input voltage is maintained within predetermined limits characterised in that the converter comprises a step-up voltage converter which does not break the input current path.
Claim 6
Dependent Claim
90 words
A switched mode power supply, operative on unidirectional current derived by a full wave rectifier from an alternating supply, to provide a unidirectional output current to a load, the power supply including a converter circuit and control means responsive to the load or input current to generate a reference signal to control the converter circuit so that the phase difference between the input current and input voltage is maintained within predetermined limits characterised in that the converter comprises a step-up voltage converter which does not break the input current path.
Claim 7
Dependent Claim
38 words
A power supply according to Claim 4 in which the converter circuit is arranged to respond to the reference signal to match the waveform of the input current to the waveform of the input voltage within predetermined limits.
Claim 8
Dependent Claim
43 words
A power supply according to Claim 4 or Claim 5 including means responsive to the output voltage of the power supply arranged to vary the reference signal to maintain the output voltage substantially constant within operating limits on variations in the alternating supply.
Claim 9
Dependent Claim
32 words
A power supply according to any preceding claim including an overvoltage protection circuit comprising means for comparing the output voltage with a reference voltage to prevent the output voltage exceeding said reference.
Claim 10
Dependent Claim
23 words
A power supply according to any preceding claim arranged to operate fluorescent or other discharge lamps and including means for starting said lamps.
References Cited (Backward Citations)
No citation records indexed.
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