GaN Power Driver Charge Pump Eliminates Inductor Parasitics
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Solution Overview
Problem
Conventional power circuits face parasitic effects from inductors that interfere with boost voltage, necessitating a solution to eliminate these effects and improve driving capability in GaN power devices.
Innovation Solution
A power circuit design incorporating a voltage converter, UVLO circuit, high-side and low-side transistors, a charge pump, and a pre-driver with a hysteresis circuit to generate a high-side voltage exceeding the supply voltage, coupled with an ESD protection circuit to manage external voltage stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional charge pump is used to boost supply voltage, then the power transistor can be driven, but parasitic effects from inductors interfere with the boost voltage
Solution Approach 1:
The patent extracts the harmful inductor component from the driving circuit by implementing a capacitor-based charge pump architecture. This eliminates the parasitic effects associated with inductors while retaining the voltage boosting functionality needed to drive the high-side power transistor.
Solution Approach 2:
The patent changes the fundamental operating parameters of the charge pump by transitioning from an inductor-based design to a capacitor-based design. This parameter change eliminates parasitic inductance while achieving the required voltage multiplication through capacitive switching and energy transfer.
2Power
If the supply voltage is increased to improve driving capability, then the power transistor can be fully turned on, but the circuit complexity increases
Solution Approach 1:
The patent merges the voltage boosting function with the existing power stage by integrating the capacitor-based charge pump directly into the driver circuitry. This combination achieves high-side voltage generation without requiring separate complex voltage regulation stages, thereby limiting the increase in overall 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
The solution effectively eliminates parasitic effects and enhances driving capability by generating a high-side voltage that exceeds the supply voltage, improving the performance of GaN power devices and protecting against electrostatic discharges.
Implementation Method 1
The charge pump is coupled to the high-side node and the driving node, which is configured to generate the high-side voltage that exceeds the supply voltage
Implementation Method 2
The UVLO circuit generates the UVLO signal when the external voltage exceeds a threshold
Implementation Method 3
The first hysteresis circuit is configured to provide a hysteresis for the control signal
Data Source
AI summary
A power circuit includes a voltage converter, an UVLO circuit, a power transistor, and a driving circuit. The voltage converter converts an external voltage to a supply voltage according to an UVLO signal. The UVLO circuit generates the UVLO signal when the external voltage exceeds a threshold. The power transistor draws a power current according to a voltage of a driving node. The driving circuit includes a high-side transistor, a low-side transistor, a charge pump, and a pre-driver. The high-side transistor provides the supply voltage to the driving node according to a high-side voltage of a high-side node. The low-side transistor couples the driving node to a ground according to a first internal signal. The charge pump generates a high-side voltage that exceeds the supply voltage according to the first internal signal. The pre-driver generates the first internal signal according to a control signal.