Programmable Gate Voltage Control for Power Module On-Resistance
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Solution Overview
Problem
Conventional power conversion systems face challenges in adjusting gate-source voltage (Vgs) to prevent damage to power modules due to excessive supply voltage, slow response in thermal management, and damage during short circuits, necessitating fast on-resistance adjustments.
Innovation Solution
Implementing a gate driver with a controller and buffer to adjust gate voltage (Vgs) using a reference voltage (Vref) that is less than the supply voltage, enabling rapid adjustment of on-resistance and preventing damage by disabling the driver and enabling the buffer to maintain Vgs at Vref during fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supply voltage to the gate driver is reduced to prevent power module damage, then the maximum gate voltage is limited, but the response speed for thermal management and short circuit protection deteriorates
Solution Approach 1:
The gate driver output is segmented into two independent voltage sources: a main supply voltage (VCC) for fast switching and a reference voltage (VREF) for safe on-state operation. This segmentation allows each voltage source to perform its specialized function without compromise - VCC provides rapid response while VREF ensures safe operating levels
Solution Approach 2:
A voltage selection mechanism acts as an intermediary between the two voltage sources and the power module gate. This intermediary selectively connects either VCC or VREF to the gate based on operational requirements, enabling fast response during switching transitions and safe voltage limitation during on-state operation
2Device complexity
If conventional gate drivers are used with fixed supply voltage, then the circuit is simple, but the ability to dynamically adjust on-resistance for thermal management deteriorates
Solution Approach 1:
The gate driver transitions from a static fixed-voltage design to a dynamic dual-voltage system. The voltage selection mechanism dynamically switches between VCC and VREF based on real-time operational needs, enabling adaptive on-resistance control for thermal management while maintaining relatively simple circuit architecture
Solution Approach 2:
The system changes the gate voltage parameter dynamically by selecting between two discrete voltage levels (VCC and VREF). This parameter change capability enables adaptation to different operating conditions - full voltage for fast switching and reduced voltage for thermal management - without requiring complex continuous regulation circuitry
3Productivity
If the gate voltage is increased to reduce on-resistance for high current operation, then the current handling capability is improved, but the risk of damage during fault conditions increases
Solution Approach 1:
The reference voltage VREF serves as a pre-prepared protective cushion for fault conditions. By maintaining VREF at a safe voltage level that limits peak current, the system has a ready protective mechanism that can be activated during short circuits or overload conditions, preventing damage without compromising normal high-current operation capability
Data Source
AI summary
Semiconductor devices, systems and methods are described. A semiconductor device can include a driver configured to output a gate current to drive a power module. The semiconductor device can further include a buffer configured to buffer a reference voltage that is less than a supply voltage being provided to the driver. The semiconductor device can further include a controller configured to determine a gate voltage of the power module is equivalent to the reference voltage. The controller can, in response to determination that the gate voltage is equivalent to the reference voltage, disable the driver to cause the driver to stop providing the gate current to the power module and enable the buffer to supply the reference voltage to the power module.