Power limiting for flyback converter
First Claim
1. A power circuit comprising:
- a transformer arranged to store energy between a primary-side of the power circuit and a secondary-side of the power circuit;
a primary switch coupled to a primary-side winding of the transformer; and
a controller configured to;
switch-on the primary switch during a current switching cycle;
responsive to determining that a voltage indicative of a primary current through the primary switch exceeds a direct-current (DC) voltage threshold, switch-off the primary switch during the current switching cycle; and
automatically tune, according to an input voltage and an amount of primary inductance at the primary-side winding, a maximum primary current limitation threshold associated with the primary switch by at least;
responsive to determining that a peak value of the voltage during the current switching cycle is higher than a target value associated with the peak value of the voltage, increasing the target value for a subsequent switching cycle of the primary switch, wherein the target value is indicative of the maximum primary current limitation threshold; and
responsive to determining that the peak value of the voltage during the current switching cycle is lower than the target value, decreasing the target value for the subsequent switching cycle of the primary switch.
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Accused Products
Abstract
A controller of a power converter is described that after switching-on a primary switch of a power converter, detects a voltage that is indicative of a primary current through the primary switch and responsive to determining that the voltage exceeds a direct-current (DC) voltage threshold, switches-off the primary switch. The controller stores a peak value of the voltage while switching-off the primary switch, and responsive to determining that the peak value is higher or lower than a range of target values associated with the peak value of the voltage, the controller adjusts at least one of the DC voltage threshold or the range of target values for a subsequent switching cycle of the primary switch.
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Citations
18 Claims
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1. A power circuit comprising:
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a transformer arranged to store energy between a primary-side of the power circuit and a secondary-side of the power circuit; a primary switch coupled to a primary-side winding of the transformer; and a controller configured to; switch-on the primary switch during a current switching cycle; responsive to determining that a voltage indicative of a primary current through the primary switch exceeds a direct-current (DC) voltage threshold, switch-off the primary switch during the current switching cycle; and automatically tune, according to an input voltage and an amount of primary inductance at the primary-side winding, a maximum primary current limitation threshold associated with the primary switch by at least; responsive to determining that a peak value of the voltage during the current switching cycle is higher than a target value associated with the peak value of the voltage, increasing the target value for a subsequent switching cycle of the primary switch, wherein the target value is indicative of the maximum primary current limitation threshold; and responsive to determining that the peak value of the voltage during the current switching cycle is lower than the target value, decreasing the target value for the subsequent switching cycle of the primary switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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after switching-on a primary switch of a power converter, detecting, by a controller, a voltage that is indicative of a primary current through the primary switch; responsive to determining that the voltage exceeds a direct-current (DC) voltage threshold, switching-off, by the controller, the primary switch; storing, by the controller, a peak value of the voltage while switching-off the primary switch; and automatically tuning, according to an input voltage and an amount of primary inductance at a primary-side winding of the power converter, a maximum primary current limitation threshold associated with the primary switch by at least; increasing, by the controller, a range of target values for a subsequent switching cycle of the primary switch responsive to determining that a peak value of the voltage during the current switching cycle is higher than the range of target values associated with the peak value of the voltage, wherein the range of target values is indicative of the maximum primary current limitation threshold; and decreasing, by the controller, the range of target values for the subsequent switching cycle of the primary switch responsive to determining that the peak value of the voltage during the current switching cycle is lower than the range of target values. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A power circuit comprising:
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means for switching-on a primary switch of a power converter; means for detecting a voltage that is indicative of a primary current through the primary switch; means for determining whether the voltage exceeds a direct-current (DC) voltage threshold, means for switching-off the primary switch in response to determining that the voltage exceeds the DC voltage threshold; means for determining a peak value of the voltage while switching-off the primary switch; and means for automatically tuning a maximum primary current limitation threshold associated with the threshold according to an input voltage and an amount of primary inductance at a primary-side winding, wherein the means for automatically tuning comprises; means for increasing a range of target values for a subsequent switching cycle of the primary switch in response to determining that the peak value is higher than the range of target values associated with the peak value of the voltage, wherein the range of target values is indicative of the maximum primary current limitation threshold; and means for decreasing the range of target values for the subsequent switching cycle of the primary switch in response to determining that the peak value of the voltage during the current switching cycle is lower than the range of target values. - View Dependent Claims (16, 17, 18)
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Specification