GaN Voltage Regulator Self-Generated Negative Drive
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Solution Overview
Problem
Conventional voltage regulators using GaN HEMTs require a negative power supply to switch off the normally-on transistors, increasing component count and cost.
Innovation Solution
A voltage regulator design that includes a negative voltage generation circuit to generate a negative voltage based on pulse signals from the switching operation of GaN HEMTs, allowing the drive circuits to switch the transistors on and off using a negative voltage, eliminating the need for a separate negative power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative power supply is provided to switch off normally-on GaN HEMTs, then the transistors can be switched off effectively, but the number of components increases and cost increases
Solution Approach 1:
The voltage regulator circuit generates its own negative voltage internally using the switching action of the GaN HEMT itself and the LC circuit. The pulse signal from the switching operation is converted to negative voltage through the inductor and capacitor, which then feeds back to the drive circuit. This eliminates the need for an external negative power supply while maintaining the ability to switch off the normally-on transistors.
Solution Approach 2:
The circuit transforms the positive voltage pulse signals generated during switching operation into negative voltage through electromagnetic induction in the inductor and capacitive coupling. By changing the voltage polarity parameter dynamically during operation, the circuit achieves the required negative drive voltage without an external negative power supply.
2Reliability
If a negative power supply is provided to switch off normally-on GaN HEMTs, then the transistors can be switched off effectively, but the cost increases
Solution Approach 1:
The voltage regulator circuit generates its own negative voltage internally using the switching action of the GaN HEMT itself and the LC circuit. The pulse signal from the switching operation is converted to negative voltage through the inductor and capacitor, which then feeds back to the drive circuit. This eliminates the need for an external negative power supply while maintaining the ability to switch off the normally-on transistors.
Solution Approach 2:
The circuit transforms the positive voltage pulse signals generated during switching operation into negative voltage through electromagnetic induction in the inductor and capacitive coupling. By changing the voltage polarity parameter dynamically during operation, the circuit achieves the required negative drive voltage without an external negative power supply.
3Ease of operation
If conventional voltage regulator design is used with separate negative power supply, then negative voltage is available for switching, but unnecessary through currents occur during dead time
Solution Approach 1:
The circuit uses feedback control where the voltage at the connection node between the GaN HEMT and inductor is detected and used to generate the negative voltage through the LC circuit. This feedback mechanism ensures that the negative voltage is generated only when needed during switching transitions, and the timing is synchronized with the switching operation to prevent through currents during dead time.
Solution Approach 2:
The voltage regulator circuit generates its own negative voltage internally using the switching action of the GaN HEMT itself and the LC circuit. The pulse signal from the switching operation is converted to negative voltage through the inductor and capacitor, which then feeds back to the drive circuit. This eliminates the need for an external negative power supply while maintaining the ability to switch off the normally-on transistors.
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 design reduces the number of components required, lowers costs, and enhances the efficiency of the voltage regulator by effectively switching off normally-on transistors without unnecessary through currents during dead time.
Implementation Method 1
a negative voltage generation circuit that is coupled to the reference voltage, generates a negative voltage on the basis of a pulse signal generated at the connection node by switching operation of the first transistor
Data Source
AI summary
A voltage regulator includes: a normally-on first transistor coupled to an input voltage; an inductor provided between the first transistor and an output terminal; a return circuit provided between a reference voltage and a connection node of the first transistor and the inductor; a drive circuit that supplies a drive signal to a gate of the first transistor; and a negative voltage generation circuit that is coupled to the reference voltage, generates a negative voltage on the basis of a pulse signal generated at the connection node by switching operation of the first transistor, and supplies the negative voltage to the drive circuit.