Integrated Bidirectional Startup Circuit for Power Converters
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Solution Overview
Problem
Unidirectional power converters face challenges when operated in reversed configurations or bidirectional modes due to insufficient voltage at the effective output terminal, leading to a circular startup problem, and existing solutions often require additional external circuitry like voltage boosters or pre-charge circuits.
Innovation Solution
The implementation of an auxiliary circuit with an input voltage selector that can choose between two input voltages, integrated within the converter circuit, to provide sufficient power to the auxiliary circuit during startup and operation without external boosters or pre-charge circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power converters operate in reversed unidirectional or bidirectional modes, then voltage flexibility and adaptability are improved, but sufficient voltage for auxiliary circuit startup cannot be ensured
Solution Approach 1:
The voltage selector is configured to selectively couple the greater of the first voltage or the second voltage to the auxiliary circuit before the power converter starts operating. This preliminary voltage selection ensures that the auxiliary circuit receives sufficient voltage for reliable startup and operation, resolving the contradiction between operational flexibility and startup voltage sufficiency.
2Reliability
If external voltage boosters or pre-charge circuits are added, then auxiliary circuit startup voltage is ensured, but device complexity and system component quantity increase
Solution Approach 1:
The voltage selector is integrated within the power converter circuit itself, merging the auxiliary circuit power supply function with the main converter. This eliminates the need for separate external voltage boosters or pre-charge circuits, ensuring startup voltage sufficiency while reducing device complexity and component quantity.
Solution Approach 2:
The voltage selector serves multiple functions: it powers the auxiliary circuit during startup, enables reversed unidirectional operation, and supports bidirectional operation. This multi-functionality ensures reliable auxiliary circuit startup without requiring additional dedicated external circuits, thereby reducing overall system complexity.
3Device complexity
If integrated voltage selection is implemented, then device complexity is reduced, but voltage selection control capability may be compromised
Solution Approach 1:
The voltage selector is controlled based on the operational mode of the power converter. The controller automatically selects the appropriate voltage (first voltage or second voltage) for the auxiliary circuit depending on whether the converter is operating in forward mode, reversed unidirectional mode, or bidirectional mode. This feedback-based control ensures proper voltage selection while maintaining reduced device complexity through integration.
Data Source
AI summary
Circuits and methods encompassing a power converter that can be started and operated in a reversed unidirectional manner or in a bidirectional manner while providing sufficient voltage for an associated auxiliary circuit and start-up without added external circuitry for a voltage booster and/or a pre-charge circuit-that is, with zero external components or a reduced number of external components. Embodiments include an auxiliary circuit configured to selectively couple the greater of a first or a second voltage from a power converter to provide power to the auxiliary circuit. Embodiments include an auxiliary circuit configured to select a subcircuit coupled to the greater of a first or a second voltage from a power converter to provide an output for the auxiliary circuit. Embodiments include a charge pump including a gate driver configured to be selectively coupled to one of a first voltage node or second voltage node of the charge pump.