Power supply device with detection of malfunctioning
First Claim
1. A power supply device having an input terminal and an output terminal between which is connected a DC-DC converter circuit, said DC-DC converter circuit comprising:
- an isolation transformer having primary and secondary windings, isolating an input portion of the DC-DC converter circuit from an output portion of the DC-DC converter;
a power switch having a first output terminal and a control terminal; and
a driving stage having a compensation terminal on which a compensation voltage is present and receiving a biasing current, said driving stage including a control circuit having a first input terminal connected to said compensation terminal and an output terminal connected to said control terminal of said power switch;
said driving stage further including disconnection-detecting means connected to said compensation terminal and generating a signal for permanent turning-off of said power switch when said biasing current drops below a current threshold value.
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Accused Products
Abstract
The power supply device comprises a DC-DC converter circuit including a power switch and a driving stage. The driving stage has a compensation terminal on which a compensation voltage is present and which receives a biasing current, said driving stage comprising a control circuit having an output terminal connected to a control terminal of the power switch and disconnection-detecting means connected to said compensation terminal and generating a signal for permanent turning-off of said power switch when the biasing current drops below a current-threshold value. The driving stage moreover comprises over-voltage detecting means connected to the compensation terminal and generating a signal for temporary turning-off of said power switch when said compensation voltage exceeds a voltage-threshold value.
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Citations
15 Claims
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1. A power supply device having an input terminal and an output terminal between which is connected a DC-DC converter circuit, said DC-DC converter circuit comprising:
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an isolation transformer having primary and secondary windings, isolating an input portion of the DC-DC converter circuit from an output portion of the DC-DC converter;
a power switch having a first output terminal and a control terminal; and
a driving stage having a compensation terminal on which a compensation voltage is present and receiving a biasing current, said driving stage including a control circuit having a first input terminal connected to said compensation terminal and an output terminal connected to said control terminal of said power switch;
said driving stage further including disconnection-detecting means connected to said compensation terminal and generating a signal for permanent turning-off of said power switch when said biasing current drops below a current threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device comprising:
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a power control switch that operates at a variable duty cycle, having a control terminal and configured to provide power to a load;
a regulator circuit, configured to monitor a current drawn by the load and provide a compensation voltage level at a compensation node, proportionate to the current draw;
a driver circuit having an input connected to the compensation node and an output connected to the control terminal of the power switch, configured to monitor the compensation voltage at the compensation node and adjust the duty cycle of the power switch to compensate for the current draw; and
an overload detection circuit configured to the control terminal of the power switch and configured to temporarily hold the power control switch open in the event that the compensation voltage exceeds a first threshold voltage, and to latch the power control switch open in the event that the compensation voltage exceeds a second threshold voltage. - View Dependent Claims (11, 13, 14)
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12. A method comprising:
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comparing a voltage level at an output terminal of a power supply device with a first reference voltage;
providing a compensation voltage at a compensation node, proportionate to the result of the comparing step;
varying a duty cycle of a power control switch with reference to the compensation voltage of the providing step, wherein the power control switch provides current to the output terminal of the power supply device;
comparing the compensation voltage to a second reference voltage; and
latching the power control switch open if the compensation voltage exceeds the second reference voltage, wherein the latching results in permanently turning off the power supply device;
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15. A method, comprising:
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comparing a voltage level at an output terminal of a power supply device with a first reference voltage;
providing a compensation voltage at a compensation node, proportionate to the result of the comparing step;
varying a duty cycle of a power control switch with reference to the compensation voltage of the providing step, wherein the power control switch provides current to the output terminal of the power supply device;
comparing the compensation voltage to a second and third reference voltage;
opening the power control switch if the compensation voltage exceeds the second reference voltage, wherein the opening results in temporarily turning off the power supply device; and
latching the power control switch open if the compensation voltage exceeds the third reference voltage, wherein the latching results in permanently turning off the power supply device.
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Specification