LLC converter with protection circuit
AssigneeInfineon Technologies Austria AG
InventorAndrey Malinin
Life of this patent
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Abstract
An LLC (inductor-inductor-capacitor) converter, including: a primary current sensing circuit operable to sense a primary current of the LLC converter; and a protection circuit coupled between the primary current sensing circuit and power switches of the LLC converter, and operable to increase a switching frequency of the LLC converter when an amplitude of the primary current falls below a predefined low current reference value after a predefined blanking time after a phase transition of the LLC converter.
Claims17
An LLC (inductor-inductor-capacitor) converter, comprising:
- a primary current sensing circuit operable to sense a primary current of the LLC converter;
- and
- a protection circuit coupled between the primary current sensing circuit and power switches of the LLC converter, and operable to increase a switching frequency of the LLC converter when an amplitude of the primary current falls below a predefined low current reference value after a predefined blanking time after a phase transition of the LLC converter,
- wherein the protection circuit comprises:
- a low current comparator circuit operable to generate a low current signal when the amplitude of the primary current falls below the predefined low current reference value;
- a blanking timer circuit operable to reset a blanking timer signal after the phase transition, and set the blanking timer signal at the predefined blanking time after the phase transition;
- and
- a switching frequency adjustment circuit, coupled to outputs of the low current comparator circuit and the blanking timer circuit, and operable to generate a below resonance protection signal to increase the switching frequency of the LLC converter based on a combination of the low current signal and the blanking timer signal.
A method of operating an LLC (inductor-inductor-capacitor) converter, comprising:
- sensing, by a primary current sensing circuit, a primary current of the LLC converter;
- and
- increasing, by a protection circuit, a switching frequency of the LLC converter when an amplitude of the primary current falls below a predefined low current reference value after a predefined blanking time following a phase transition of the LLC converter,
- wherein the increasing the switching frequency comprises:
- generating, by a low current comparator circuit, a low current signal when the amplitude of the primary current falls below the predefined low current reference value;
- resetting, by a blanking timer circuit, a blanking timer signal after the phase transition;
- setting, by the blanking timer circuit, the blanking timer signal at the predefined blanking time after the phase transition;
- and
- generating, by a switching frequency adjustment circuit, a below resonance protection signal to increase the switching frequency of the LLC converter based on a combination of the low current signal and the blanking timer signal.
Dependencies are inferred from the claim text.