High-Voltage Contactor Driver Circuit for Fast Coil Turn-Off
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-voltage contactors face challenges in gate driver design due to their physical characteristics and varying power bridge stage configurations, necessitating improved control mechanisms for efficient and rapid operation.
Innovation Solution
A power stage circuit architecture with low RDS(ON) integrated in a chip or gate driver using low-side and high-side MOSFETs, incorporating an internal low-side MOSFET for active synchronous recirculation and a Zener diode to rapidly turn off the contactor, enabling quick disablement and minimizing delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional gate driver designs are used for high-voltage contactors, then the contactor operation can be controlled, but the turn-off speed is slow and delay is minimized poorly
Solution Approach 1:
The gate driver dynamically switches between different operating modes (drive mode, recirculation mode, and fast turn-off mode) based on the contactor state. The circuit transitions from static conventional design to dynamic adaptive control, enabling optimal performance at different operational phases and achieving rapid turn-off when needed.
Solution Approach 2:
The gate driver changes electrical parameters (voltage levels, current paths) dynamically during operation. By adjusting the gate voltage applied to the MOSFET and changing the current recirculation paths, the system achieves both efficient drive and rapid turn-off, resolving the contradiction between controlled operation and fast disablement.
2Power
If high voltage-rated MOSFETs are used for contactor operation, then the contactor can be driven at high voltage, but power dissipation increases and efficiency decreases
Solution Approach 1:
The circuit changes the voltage rating parameter of the MOSFET based on operational phase. During drive mode, high voltage MOSFETs handle the full contactor voltage. During recirculation and turn-off modes, the circuit switches to lower voltage-rated MOSFETs that have lower RDS(ON), reducing power dissipation when full voltage is not required.
Solution Approach 2:
The power stage is segmented into different functional sections with different voltage ratings. The high-voltage path is used only when necessary for contactor drive, while low-voltage paths are used for recirculation and control functions, optimizing the trade-off between power capability and efficiency.
3Loss of energy
If active synchronous recirculation mode is implemented with internal low-side MOSFET, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The gate driver merges multiple functions into a single integrated circuit: high-side and low-side MOSFET control, synchronous recirculation switching, and fast turn-off capability. By combining these functions in one device, the overall system complexity is reduced despite the advanced features, while achieving superior power efficiency.
Solution Approach 2:
The gate driver is designed as a universal multi-functional device that can operate in multiple modes (drive, recirculation, fast turn-off) and control multiple MOSFETs. This multi-functionality consolidates what would otherwise require separate circuits, managing complexity while delivering enhanced performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides rapid turn-off and disconnect of contactors, ensuring low power dissipation and high efficiency by using low voltage-rated MOSFETs, facilitating quick disablement in automotive applications.
Implementation Method 1
a Zener diode coupled across the second switching device
Implementation Method 2
an electromechanical switching device with a built-in electrical coil to generate an electromagnetic force that mechanically operates to open and close an electric contact
Data Source
AI summary
Methods and apparatus for energizing and de-energizing a coil that controls a position of a contactor. In embodiments, a first switching device is coupled between the first end of a coil and a first potential node and a second switching device is coupled between the second end of the coil and a second potential node. A third switching device is coupled across a connection of the coil and the second switching device and a zener diode coupled across the second switching device. A contactor has a position determined by a current level through the coil.