GaN HEMT RC Snubber for Drain Current Ringing Suppression
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Solution Overview
Problem
GaN-based lateral HEMTs experience increased on-resistance during switching due to substrate potential setting, leading to inefficiencies and ringing in drain current, which is exacerbated by large external gate resistances intended to suppress ringing.
Innovation Solution
Incorporating a resistance part in series with the substrate capacitance of the GaN HEMT to form an RC snubber circuit, which absorbs the energy of series resonance and suppresses ringing, allowing for reduced gate resistance and stable operation at higher dV/dt, thereby reducing switching loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a large external gate resistance is used to suppress ringing, then ringing suppression is improved, but switching loss increases and switching speed decreases
Solution Approach 1:
The gate resistance is segmented into two parts: an external gate resistance (first resistance element) and an internal gate resistance (second resistance element). This segmentation allows the external resistance to be kept small for fast switching, while the internal resistance provides the necessary damping to suppress ringing without significant power loss.
Solution Approach 2:
A capacitance element is introduced as an intermediary component connected in parallel with the second resistance element. This capacitance element mediates the interaction between the gate signal and the channel, enabling the internal resistance to suppress ringing while the external resistance remains low, thus reducing overall switching loss.
2Reliability
If substrate potential is set to source potential to suppress on-resistance increase, then on-resistance stability is improved, but ringing in drain current is exacerbated
Solution Approach 1:
The gate resistance is segmented into external and internal components, where the internal resistance (second resistance element) specifically targets the ringing issue caused by substrate potential settings, while the external resistance maintains fast switching capability.
Solution Approach 2:
The capacitance element acts as an intermediary that works with the internal resistance to suppress ringing in the drain current, counteracting the harmful effects of setting substrate potential to source potential while maintaining on-resistance stability.
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 suppresses ringing in the drain current, enabling stable operation at higher dV/dt and reducing switching loss, thus enhancing circuit efficiency.
Implementation Method 1
the resistance part is connected in series in a path including the substrate capacitance between the first drain electrode and the second terminal
Implementation Method 2
Incorporating a resistance part in series with the substrate capacitance of the GaN HEMT to form an RC snubber circuit, which absorbs the energy of series resonance and suppresses ringing
Data Source
AI summary
A semiconductor device includes a first terminal, a second terminal, a first chip, and a resistance part. The first chip includes a substrate electrically connected to the second terminal, a nitride semiconductor layer located on the substrate, a first drain electrode located on the nitride semiconductor layer and electrically connected to the first terminal, a first source electrode located on the nitride semiconductor layer and electrically connected to the second terminal, and a substrate capacitance between the first drain electrode and the substrate. The resistance part is connected in series in a path including the substrate capacitance between the first drain electrode and the second terminal.