GaN Driving Circuit With Balanced Precharge for Fast E-HEMT Switching
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Solution Overview
Problem
The lack of P-type GaN-based high-electron-mobility transistors (HEMTs) in the GaN process poses a challenge for designers in developing GaN-based driving circuits, limiting the performance of GaN-based high-electron-mobility transistors (HEMTs) in terms of frequency, power supply voltage, and temperature.
Innovation Solution
A driving circuit design utilizing enhancement-mode and depletion-mode N-type HEMTs, with balanced precharging circuitry, is developed to drive power E-HEMTs, eliminating the need for P-type HEMTs and reducing design complexity by fabricating all components using the GaN process, thereby enhancing switching frequency and reducing voltage push-up and pull-down durations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If P-type GaN-based HEMTs are used in the driving circuit, then the circuit design complexity increases and external CMOS drivers are required, but the switching frequency and voltage control performance improve
Solution Approach 1:
The invention extracts and eliminates the requirement for P-type HEMTs and external CMOS drivers from the GaN-based driving circuit. By using only N-type HEMTs with balanced precharging circuitry, the design removes complex components while maintaining driving capability through alternative circuit topologies that generate necessary voltage levels internally.
Solution Approach 2:
The N-type HEMTs in the invention perform multiple functions: they serve as both the power switching devices and the driving circuit elements. The balanced precharging circuitry enables the same N-type HEMT technology to provide both voltage push-up and pull-down capabilities, eliminating the need for separate P-type devices or external drivers.
2Duration of action of moving object
If balanced precharging circuitry is implemented, then voltage push-up and pull-down durations are reduced and E-HEMTs are fully turned on, but the circuit complexity and manufacturing steps increase
Solution Approach 1:
The balanced precharging circuitry performs preliminary voltage preparation before the main switching action. By pre-charging the gate voltage to the appropriate level, the circuit ensures that E-HEMTs are fully turned on during positive voltage cycles and rapidly pulled down during negative cycles, reducing transition durations without requiring complex external control.
3Ease of manufacture
If all components are fabricated using the GaN process, then the need for external CMOS drivers is eliminated and integration is improved, but the design flexibility and available transistor types are limited
Solution Approach 1:
The invention compensates for the limited transistor types in GaN process by changing operational parameters and circuit topology. By using balanced precharging circuitry and carefully selected device configurations, the design achieves the necessary voltage control and driving capability using only N-type HEMTs, effectively adapting the limited technology to meet performance requirements.
Data Source
AI summary
A driving circuit includes a first driving device configured to drive a power device, a first precharge circuit and a first predriving circuit. The first predriving circuit is electrically connected to the first precharge circuit and the first driving device. The first precharge circuit is configured to, in response to an input signal of the driving circuit having a first signal level, generate a first precharging voltage. The first precharge circuit is further configured to, in response to the input signal having a second signal level different from the first signal level, fully turn on, based on the first precharging voltage, a first device in the first precharge circuit to supply a first boost voltage to the first predriving circuit to drive the first driving device.