ORing MOSFET Gate-Source Voltage Regulation in Power Supplies
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Solution Overview
Problem
Conventional power supplies with ORing MOSFETs face damage due to excessive voltage differences between the gate and source of the ORing MOSFETs, particularly when the main output terminal grounds during power-on or short-circuit protection, exceeding the rated voltage threshold.
Innovation Solution
Incorporation of a voltage regulating unit that generates a control voltage to stabilize the voltage difference between the gate and source of the ORing MOSFETs to be below the rated threshold, using a reference voltage input from the main output terminal to regulate the control voltage through the driving unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary power module is turned on first or short-circuit protection is performed on the main output terminal, then the main output terminal voltage becomes 0V, but the auxiliary output voltage remains normal, causing excessive voltage difference between gate and source of ORing MOSFETs that exceeds rated voltage threshold
Solution Approach 1:
The patent applies preliminary action by introducing a voltage regulating unit that proactively regulates the control voltage before the excessive voltage difference can damage the MOSFETs. The voltage regulating unit receives reference voltage from the main output terminal and adjusts the control voltage to the driving unit in advance, ensuring that even when the auxiliary power module is turned on first or short-circuit protection is performed, the gate-source voltage difference remains within safe limits. This preventive measure eliminates the need for MOSFET replacement and ensures continuous reliable operation.
2Ease of operation
If the control voltage is directly provided by the auxiliary power module without regulation, then the driving unit can control the ORing MOSFETs, but the voltage difference between gate and source may exceed rated threshold during abnormal conditions
Solution Approach 1:
The patent applies the intermediary principle by introducing a voltage regulating unit as a mediator between the auxiliary power module and the driving unit. The voltage regulating unit receives the control voltage from the auxiliary power module and transforms it into a regulated control voltage that is safely applied to the driving unit. This intermediary component ensures that the driving unit can operate the ORing MOSFETs effectively while the voltage regulating unit protects the MOSFETs by limiting the gate-source voltage difference to within rated thresholds, even during abnormal operating conditions.
Data Source
AI summary
A power supply having ORing MOSFETs mounts a voltage regulating unit between a main power module and an auxiliary power module of a secondary side of the power supply. The voltage regulating unit regulates a control voltage received by a driving unit, such that a voltage difference between a gate voltage and a source voltage of one of the ORing MOSFETs can be less than a rated voltage threshold for avoiding damaging the one ORing MOSFET.