GaN Power Circuit Driving Without Charge Pump
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Solution Overview
Problem
Conventional power circuits require a charge pump to boost supply voltage for driving GaN power transistors, which complicates the design and efficiency of power circuits due to the need for high-side transistors to be fully turned ON, requiring high-side voltage higher than the operation voltage.
Innovation Solution
A power circuit with a driving circuit comprising a high-side transistor, low-side transistor, and high-side driver, where the high-side driver uses a plurality of N-type transistors to provide a high voltage exceeding the operational gate voltage, and a regulator down-converts supply voltage to appropriate levels for the transistors, ensuring efficient operation of GaN transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge pump is used to boost supply voltage for driving GaN power transistors, then the high-side transistor can be fully turned ON, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the charge pump component from the power circuit by using GaN HEMT transistors with inherently higher electron mobility and lower on-resistance, which can be fully turned ON with lower voltage requirements, thereby reducing device complexity while maintaining reliable switching operation
Solution Approach 2:
The patent changes the material parameter from traditional silicon-based transistors to GaN HEMT transistors, which have fundamentally different electrical characteristics including higher breakdown voltage and lower on-resistance, allowing the circuit to operate without a charge pump while still achieving full transistor turn-on
2Reliability
If high-side voltage is made higher than operation voltage to fully turn ON the high-side transistor, then the transistor switching is reliable, but the energy consumption increases
Solution Approach 1:
The patent removes the voltage boosting mechanism (charge pump) by utilizing GaN HEMT transistors that can achieve full conduction with lower gate-to-source voltage due to their superior material properties, thereby eliminating the energy loss associated with voltage multiplication
Solution Approach 2:
The GaN HEMT transistor inherently provides the necessary voltage characteristics for full turn-on through its material properties without requiring external voltage boosting circuitry, making the system self-sufficient and energy-efficient
3Ease of manufacture
If conventional silicon-based transistors are used, then the circuit design is straightforward, but the power efficiency is limited
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to gallium nitride (GaN), which provides higher electron mobility and lower on-resistance, resulting in reduced power dissipation while maintaining design simplicity through the use of standard HEMT transistor configurations
Data Source
AI summary
A power circuit includes a power transistor and a driving circuit. The power transistor sinks a current according to a driving voltage. The driving circuit includes a driver which includes a high-side transistor, a low-side transistor, a high-side driver, and a first pre-driver. The high-side transistor provides a low voltage to the driving voltage according to a high-side voltage. The low-side transistor pulls the driving voltage to a ground according to a control signal. The high-side driver includes a plurality of N-type transistors and provides a high voltage to the high-side voltage according to the control signal. The high voltage exceeds an operational gate voltage of the N-type transistors.