EP0190493A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Disabled diac start-up technique for a power supply
Assignee: MODERN POWER CONVERSION Inc
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Filing: 1985-11-28
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Granted: —
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Expires: 2005-11-28
Abstract
Abstract An AC to DC or DC to DC switched mode power supply is provided with a switching means, a control circuit for the switching means and a start-up circuit including voltage actuated means. The switching means, start-up circuit and voltage actuated means are so connected that the switching neans is switched on when the input voltage applied to the ioltage-actuated means exceeds a certain threshold on ;tart-up and the voltage-actuated means is disabled during normal operation by limiting the voltage applied to the voltage-actuated means to below the threshold.
Inventors
- 👤 Brian Lees
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 14:29
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33538; H02M3/33546; H02M3/33553; H02M3/33507; H02M3/337; H02M3/3376; H02M3/3378
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
147 words
An AC to DC or DC to DC switched mode power supply system having an input, a power transformer with a primary connected to the input and with at least one output, switching means connected in series with a primary and the input, a control circuit operable to control switching of the switching means after start-up and a start-up circuit comprising voltage-actuated means which conducts only when voltage applied thereto exceeds a predetermined value less than maximum input voltage, said voltage-actuated means being connected to receive start-up input voltage and being connected to the switching means to cause the switching means to switch on when the voltage-actuated means is caused tn conduct hy increase of input voltage on start-up, and means for disabling the voltage-actuated means during normal operation of the power supply by preventing a voltage applied to the voltage-actuated means from reaching a predetermined value.
Claim 2
Dependent Claim
147 words
An AC to DC or DC to DC switched mode power supply system having an input, a power transformer with a primary connected to the input and with at least one output, switching means connected in series with a primary and the input, a control circuit operable to control switching of the switching means after start-up and a start-up circuit comprising voltage-actuated means which conducts only when voltage applied thereto exceeds a predetermined value less than maximum input voltage, said voltage-actuated means being connected to receive start-up input voltage and being connected to the switching means to cause the switching means to switch on when the voltage-actuated means is caused tn conduct hy increase of input voltage on start-up, and means for disabling the voltage-actuated means during normal operation of the power supply by preventing a voltage applied to the voltage-actuated means from reaching a predetermined value.
Claim 3
Dependent Claim
46 words
A power supply system according to claim 1 wherein the start-up circuit also comprises resistor-capacitor means connected to the voltage-actuated means to cause start-up voltage applied to the voltage-actuated means to increase at a rate slower than the rate of start-up voltage increase at the input.
Claim 4
Dependent Claim
66 words
A power supply system according to claim 1 wherein the disabling means comprises capacitor means connected to the voltage-actuated means, and resistor means connected between the capacitor means and the power transformer primary side of the switching means to maintain said capacitor means sufficiently discharged during normal operation of the power supply to prevent the voltage applied to the voltage-actuated means from exceeding the predetermined value.
Claim 5
Dependent Claim
102 words
A power supply system according to claim 1 wherein the start-up circuit also comprises resistor-capacitor means connected to the voltage-actuated means to cause start-up voltage applied to the voltage-actuated means to increase at a rate slower than the rate of increase of start-up voltage at the input, and the disabling means comprises a resistor means connected between the resistor-capacitor means and the power transformer primary side of the switching means to maintain the capacitor component of said resistor-capacitor means sufficiently discharged during normal operation of the power supply to prevent the voltage applied to the voltage-actuated means from exceeding the predetermined value.
Claim 6
Dependent Claim
15 words
A power supply system according to claim 1 wherein the voltage-actuated means comprises a triac.
Claim 7
Dependent Claim
16 words
A power supply system according to claim 1 wherein the voltage-actuated means comprises a four-layer diode.
Claim 8
Dependent Claim
16 words
A power supply system according to claim 1 wherein the voltage-actuated means comprises a uni-junction transistor.
Claim 9
Dependent Claim
17 words
A power supply system according to claim 1 wherein the switching means comprises at least one transistor.
Claim 10
Dependent Claim
17 words
A power supply system according to claim 1 wherein the power supply comprises a fly-back bi-polar arrangement.
Claim 11
Dependent Claim
19 words
A power supply system according to claim 1 wherein the power supply comprises half- or full-bridge power FET arrangement.
References Cited (Backward Citations)
No citation records indexed.
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