Adjustable Charge Pump Gate Driver for Active dv/dt Control
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Solution Overview
Problem
Existing active gate drivers for wide bandgap devices require additional passive components, switches, power supplies, and dedicated timing control, leading to increased complexity and cost, and are limited by overcharging issues.
Innovation Solution
A charge pump gate driver circuit with an adjustable pump voltage that regulates switching speeds without additional power supplies or timing circuits, using MOSFETs, diodes, and flying capacitors to control dv/dt and di/dt dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional passive components, switches, and power supplies are added to existing active gate drivers, then dv/dt and di/dt control capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the charge pump circuit and gate driver into a single integrated device. The charge pump generates adjustable pump voltages that directly control the gate driver output, merging voltage generation and gate driving functions into one unit, thereby reducing the need for separate power supplies and control circuits while maintaining dv/dt and di/dt control capability
Solution Approach 2:
The integrated charge pump gate driver serves multiple functions: it generates the gate driving voltage, controls dv/dt through adjustable pump voltage, controls di/dt through gate resistance, and provides overcharge protection. This multi-functionality eliminates the need for separate dedicated timing control circuits and overcharge protection circuits, reducing overall device complexity
2Adaptability or versatility
If additional passive components, switches, and power supplies are added to existing active gate drivers, then dv/dt and di/dt control capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the charge pump circuit and gate driver into a single integrated device, reducing the total component count and assembly steps. This integration directly lowers manufacturing cost by eliminating separate power supplies, timing control circuits, and overcharge protection circuits that would otherwise be required
Solution Approach 2:
The charge pump automatically adjusts its output voltage based on the gate driver's power device charging state, providing self-regulating dv/dt control without external timing control circuits. This self-service capability eliminates the need for additional control components, reducing both complexity and manufacturing cost
3Adaptability or versatility
If additional power supplies and timing control circuits are added, then adjustable pump voltage capability is improved, but circuit space requirement increases
Solution Approach 1:
The patent integrates the charge pump and gate driver into a single compact device, with the charge pump located adjacent to the gate driver. This integration eliminates the space required for separate power supplies and timing control circuits while maintaining adjustable pump voltage capability through internal voltage regulation
Solution Approach 2:
The charge pump circuit is nested within or adjacent to the gate driver structure, with the pump capacitor positioned to directly couple with the gate driver output. This nested arrangement allows the pump voltage to be generated and applied in close proximity, minimizing the space required for voltage transmission and control circuitry
4Reliability
If dedicated timing control is implemented, then overcharge protection is improved, but device complexity increases
Solution Approach 1:
The charge pump incorporates feedback mechanisms that monitor the gate driver's power device charging state and automatically adjust the pump voltage output accordingly. This feedback control provides overcharge protection by reducing or stopping pump voltage when the gate capacitor reaches full charge, eliminating the need for external timing control circuits
Solution Approach 2:
The charge pump automatically regulates its own output voltage based on the load conditions of the gate driver, providing self-protection against overcharge. This self-service capability is achieved through internal voltage sensing and regulation circuitry that adjusts pump voltage in real-time without external intervention, reducing control circuit complexity
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
Enables flexible and fast regulation of switching speeds during each cycle, reducing circuit costs and space requirements while avoiding overcharging, and maintaining efficient dv/dt and di/dt control.
Implementation Method 1
The CPGD comprises two charge pumps (CPs), each including one pair of MOSFETs, one diode and one flying capacitor
Data Source
AI summary
The disclosure relates to devices, systems and methods implementing a charge pump gate driver (CPGD) that offers adjustable pump voltage, enabling online and active dv/dt and di/dt control for power devices, including the wide bandgap devices, such as SiC MOSFETs and GaN HEMTs. The disclosed CPGD allows a flexible pump voltage adjustment through the pre-charging interval control. Both the turn-on and turn-off switching speed (both dv/dt and di/dt) of power devices can be online regulated rapidly within each switching cycle, without interrupting the power converter operation. The disclosed CPGD has a simple structure and eliminates the extra power supplies to reduce circuit cost and footprint.