Circuit for determining the end of a demagnetization stroke of a switched mode power supply
First Claim
1. A circuit for a switched mode power supply having a winding, the circuit comprising:
- an input configured to receive a winding voltage derived from the winding;
a differentiation element configured to differentiate the winding voltage with respect to time in order to determine a derivative signal and compare the derivative signal with a threshold value;
a steady state detector configured to set a zero derivative signal when the derivative signal has not exceeded the threshold value for a predetermined period of time, anda logic arrangement configured to identify an end of a demagnetization stroke of the switched mode power supply when the derivative signal crosses a final threshold value after the zero derivative signal has been set.
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Accused Products
Abstract
A circuit for a switched mode power supply having a winding. The circuit comprising: an input configured to receive a winding voltage derived from the winding; a differentiation element configured to differentiate the winding voltage with respect to time in order to determine a derivative signal and compare the derivative signal with a threshold value; a steady state detector configured to set a zero derivative signal when the derivative signal has not exceeded the threshold value for a predetermined period of time, and a logic arrangement configured to identify an end of a demagnetization stroke of the switched mode power supply when the derivative signal crosses a final threshold value after the zero derivative signal has been set.
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Citations
12 Claims
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1. A circuit for a switched mode power supply having a winding, the circuit comprising:
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an input configured to receive a winding voltage derived from the winding; a differentiation element configured to differentiate the winding voltage with respect to time in order to determine a derivative signal and compare the derivative signal with a threshold value; a steady state detector configured to set a zero derivative signal when the derivative signal has not exceeded the threshold value for a predetermined period of time, and a logic arrangement configured to identify an end of a demagnetization stroke of the switched mode power supply when the derivative signal crosses a final threshold value after the zero derivative signal has been set. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating a circuit for a switched mode power supply having a winding, the method comprising:
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receiving a winding voltage derived from the winding; differentiating the winding voltage with respect to time in order to determine a derivative signal; comparing the derivative signal with a threshold value; setting a zero derivative signal when the derivative signal has not exceeded the threshold value for a predetermined interval of time; identifying an end of a demagnetization stroke of the switched mode power supply when the derivative signal crosses a final threshold value after the zero derivative signal has been set. - View Dependent Claims (12)
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Specification