GaN Switch Driver Feedback Control for Lower Gate Overcharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switch driver circuitry for GaN field effect transistors often overcharges the gate, leading to inefficient power consumption due to excessive current flow, especially when switches are repeatedly turned on and off at a high rate.
Innovation Solution
A switch driver circuitry that includes a first current source to temporarily boost the gate voltage and a second current source to maintain the switch in an ON-state, minimizing gate overcharging by varying the current magnitude based on the voltage, and using a feedback mechanism to deactivate the first current source when a threshold is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional RC network or reaction time-based driver circuitry is used to control GaN switches, then the switch can be turned on and off, but gate overcharging occurs leading to excessive current flow and high power consumption
Solution Approach 1:
The patent employs a feedback mechanism where the driver circuitry monitors the gate voltage of the GaN switch and adjusts the drive current accordingly. When the gate voltage reaches a predetermined threshold, the feedback signal causes the driver to reduce or stop current flow, preventing gate overcharging. This closed-loop control ensures accurate gate charge management while minimizing power consumption during switching operations.
Solution Approach 2:
The driver circuitry dynamically adjusts its output characteristics based on real-time gate voltage conditions. The circuit transitions from a high-current charging phase to a low-current or zero-current holding phase, optimizing the balance between switching speed and power consumption. This dynamic behavior allows the driver to provide sufficient current for rapid switching while avoiding excessive current that would waste power.
2Speed
If high current is supplied to the gate to ensure rapid switching, then switching speed improves, but power consumption increases due to gate overcharging
Solution Approach 1:
The driver circuitry implements a two-stage periodic action: an initial high-current pulse to rapidly charge the gate and achieve fast switching, followed by a second stage where current is reduced or eliminated once the gate voltage reaches the threshold. This periodic current delivery pattern maintains high switching speed while minimizing energy loss from continuous high current flow.
Solution Approach 2:
The patent applies partial action by providing excessive current only during the brief initial charging phase necessary for rapid switching, then reducing current to the minimum required to maintain the gate voltage. This approach achieves fast switching performance without the continuous excessive current that would cause unnecessary power dissipation.
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 approach reduces power consumption by optimizing switching loss and ensuring efficient activation and maintenance of GaN switches, compensating for process variations and maintaining consistent performance across different RDSON classes.
Implementation Method 1
The first current source may be or include a field effect transistor that outputs the first current to a gate node of the main switch. Output of the first current increases a magnitude of the voltage applied to the gate node of the main switch.
Implementation Method 2
The increased magnitude of the voltage applied to the gate node of the main switch results in self turn off or an increase in resistance of the switch. The increased resistance reduces a magnitude of the first current supplied to the gate node of the main switch
Implementation Method 3
The RDS on resistance between a drain node of the field effect transistor and the source node of the field effect transistor increases during operation in response to a decrease in a gate-to-source voltage between a gate node of the field effect transistor and the source node of the field effect transistor
Data Source
AI summary
A power converter assembly as discussed herein can be configured to include: a first input operative to receive a first control signal indicating how to control a main switch; switch driver circuitry operative to convert the first control signal into a second control signal; and an output operative to output the second control signal to the main switch, the second control signal including first current supplied from a first current source of the switch driver circuitry to the main switch, a magnitude of the first current varying based on a voltage magnitude of the second control signal.