Oscillator-Powered Gate Drive Supply for High-Voltage Switches
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Solution Overview
Problem
Existing semiconductor switching element drive circuits face challenges in generating a supply voltage efficiently, particularly for high-blocking voltage semiconductor switching elements, as they require a separate supply voltage for operation in the on-state or off-state, which is not effectively addressed by traditional methods.
Innovation Solution
A circuit arrangement that includes a free-running oscillator generating an oscillating output voltage, which is then used by a voltage supply circuit to provide the necessary supply voltage for the drive circuit of the semiconductor switching element, utilizing capacitive or inductive coupling and rectification to ensure efficient voltage regulation and recharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional bootstrap circuits are used to generate supply voltage for drive circuits, then the drive circuit can operate semiconductor switching elements, but the supply voltage generation is inefficient and causes power loss
Solution Approach 1:
The patent combines the oscillator circuit and voltage supply circuit into an integrated unit that generates both the drive signal and supply voltage simultaneously. The oscillator output directly charges the storage element through a coupling circuit, eliminating the need for separate bootstrap circuits and reducing overall power loss while maintaining drive functionality.
Solution Approach 2:
The patent employs a free-running oscillator that generates periodic oscillating signals to charge the storage element in cycles. This periodic charging mechanism ensures continuous supply voltage regeneration during both on-state and off-state operations, improving efficiency compared to traditional continuous bootstrap circuits.
2Reliability
If separate supply voltage circuits are provided for drive circuits of high-blocking voltage semiconductor switching elements, then the drive function is ensured, but the device complexity and power loss increase
Solution Approach 1:
The oscillator circuit serves multiple functions: it generates the drive signal for the semiconductor switching element and simultaneously generates the supply voltage for the drive circuit through its oscillating output. This multi-functional design ensures reliable drive operation while reducing the need for separate dedicated supply voltage circuits.
Solution Approach 2:
The voltage supply circuit is designed to recharge its own storage element using the oscillating output voltage from the same oscillator that drives the switching element. This self-service mechanism eliminates the need for external supply voltage sources, reducing device complexity while maintaining operational reliability.
3Ease of operation
If bootstrap circuits are used for supply voltage generation, then the drive signal can be generated, but the supply voltage regulation is insufficient and causes power loss
Solution Approach 1:
The patent incorporates a feedback mechanism where the oscillating output voltage is used to monitor and regulate the charging of the storage element. The coupling circuit between the oscillator and storage element provides automatic voltage regulation, ensuring the supply voltage remains adequate while minimizing power loss through efficient energy transfer.
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
This solution enables efficient generation and regulation of the supply voltage for semiconductor switching elements, ensuring reliable operation across various voltage levels and reducing power loss by utilizing the oscillating output voltage to recharge storage elements during both on-state and off-state operations.
Implementation Method 1
a free-running oscillator (5) having supply terminals and an oscillator output (53), the oscillator output being connected between the input voltage terminals by using its supply terminals, and the oscillator being designed to generate an oscillating output voltage at the oscillator output
Implementation Method 2
utilizing capacitive or inductive coupling and rectification to ensure efficient voltage regulation and recharging
Implementation Method 3
utilizing capacitive or inductive coupling and rectification to ensure efficient voltage regulation and recharging
Implementation Method 4
utilizing capacitive or inductive coupling and rectification to ensure efficient voltage regulation and recharging
Data Source
AI summary
One embodiment of a circuit arrangement includes first and second input voltage terminals for applying an input voltage, and at least one first semiconductor switching element having a drive terminal and a load path, the load path being connected between the input voltage terminals. A drive circuit is configured to receive a supply voltage, and has a drive output connected to the drive terminal of the at least one semiconductor switching element. A free-running oscillator is configured to generate an oscillating output voltage. A voltage supply circuit is provided for receiving the oscillating output voltage or a voltage dependent on the oscillating output voltage, and for providing the supply voltage of the drive circuit.