Overcurrent protection in a power converter
AssigneePower Integrations, Inc.
InventorRAJKO DUVNJAK
Life of this patent
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Abstract
An LLC resonant converter controller comprising an overcurrent protection circuit coupled to receive a current sense signal representative of current in a primary winding, wherein the overcurrent protection circuit outputs an overcurrent signal when the perturbed current sense signal is above a low threshold for a number of consecutive switching cycles. The LLC resonant converter controller further includes a control circuit coupled to generate a high side drive signal and a low side drive signal in response to a feedback signal representative of an output of an LLC resonant converter is further coupled to receive the overcurrent signal and is operable to disable switching of the first power switch and second power switch in response to the overcurrent signal.
Claims18
An LLC resonant converter controller, comprising:
- an overcurrent protection circuit coupled to receive a current sense signal representative of current in a primary winding, wherein the overcurrent protection circuit perturbs the current sense signal to produce a perturbed current sense signal and is coupled to output an overcurrent signal when the perturbed current sense signal is above a low threshold for a number of consecutive switching cycles, wherein the overcurrent protection circuit comprises:
- a differentiator circuit coupled to generate a differentiator signal in response to receiving a low side drive signal, wherein the differentiator signal and the current sense signal are coupled to form the perturbed current sense signal;
- a first comparator coupled to generate a high overload signal when the perturbed current signal is greater than a high threshold reference;
- a second comparator coupled to generate a low overload signal when the perturbed current signal is greater than a low threshold reference;
- and
- a logic gate having a first input coupled to an output of the first comparator, and a second input coupled to an output of the second comparator, wherein the logic gate is coupled to generate the overcurrent signal in response to the high overload signal or the low overload signal;
- and
- a control circuit coupled to generate a high side drive signal and the low side drive signal in response to a feedback signal representative of an output of a resonant converter to control switching of a first power switch and a second power switch, wherein the control circuit is further coupled to receive the overcurrent signal and is operable to disable switching of the first power switch and the second power switch in response to the overcurrent signal.
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A resonant power converter, comprising:
- an energy transfer element coupled between an input of the resonant power converter and an output of the power converter;
- a first power switch coupled to the input of the power converter and the energy transfer element;
- a second power switch coupled to the first power switch;
- and
- a resonant converter controller, wherein the resonant converter controller includes:
- an overcurrent protection circuit coupled to receive a current sense signal representative of current in a primary winding, wherein the overcurrent protection circuit perturbs the current sense signal to produce a perturbed current sense signal and is coupled to output an overcurrent signal when the perturbed current sense signal is above a low threshold for a number of consecutive switching cycles, wherein the overcurrent protection circuit comprises;
- a differentiator circuit coupled to generate a differentiator signal in response to receiving a low side drive signal, wherein the differentiator signal and the current sense signal are combined to form the perturbed current sense signal;
- a first comparator coupled to generate a high overload signal when the perturbed current signal is greater than a high threshold reference;
- a second comparator coupled to generate a low overload signal when the perturbed signal is greater than a low threshold reference;
- and
- a logic gate having a first input coupled to an output of the first comparator, and a second input coupled to an output of the second comparator, wherein the logic gate is coupled to generate the overcurrent signal in response to the high overload signal or the low overload signal;
- and
- a control circuit coupled to generate a high side drive signal and the low side drive signal in response to a feedback signal representative of an output of the resonant power converter to control switching of the first power switch and the second power switch, wherein the control circuit is further coupled to receive the overcurrent signal and is operable to disable switching of the first power switch and the second power switch in response to the overcurrent signal.
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Dependencies are inferred from the claim text.