Integrated Driver Circuit Using GaN for Startup Voltage Withstand
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Solution Overview
Problem
In switched capacitor DC/DC converters, the withstand voltage of transistors is inadequate during startup and normal operation, affecting safety and efficiency due to the use of identical transistors with lower voltage ratings.
Innovation Solution
An integrated driver circuit using a high-voltage gallium nitride (GaN) power transistor and a silicon transistor, where the GaN transistor handles high voltages and has lower on-resistance and parasitic capacitance, is employed between the input and reference ground, ensuring reliable operation and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If identical transistors with lower voltage ratings are used in switched capacitor DC/DC converters, then device complexity is reduced and manufacturing is simplified, but withstand voltage capability deteriorates during startup and normal operation
Solution Approach 1:
The patent segments the transistor requirements by creating two distinct transistor types: a first transistor for handling high voltage during startup and a second transistor for normal operation. This segmentation allows each transistor to be optimized for its specific voltage requirement, resolving the contradiction between manufacturing simplicity and voltage withstand capability.
Solution Approach 2:
The patent applies local quality by assigning different voltage ratings to different transistors based on their specific operational requirements. The first transistor is designed with higher voltage rating for startup conditions, while the second transistor has lower voltage rating optimized for normal operation, allowing each component to have the precise quality needed for its location in the circuit.
2Reliability
If high-voltage GaN transistors are used to handle startup voltages, then withstand voltage capability and efficiency are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements a dynamic configuration where the circuit automatically switches between the first GaN transistor during startup and the second silicon transistor during normal operation. This dynamic approach allows the system to adapt its transistor usage based on operational conditions, achieving high voltage capability when needed while maintaining simpler operation during steady state.
Solution Approach 2:
The control circuit acts as an intermediary that manages the switching between different transistor types. It monitors operational conditions and activates the appropriate transistor, thereby mediating between the high-voltage GaN transistor and the lower-voltage silicon transistor to resolve the complexity of managing multiple transistor types.
3Device complexity
If identical transistors are used throughout operation, then device simplicity is maintained, but efficiency deteriorates due to higher parasitic capacitance in silicon transistors at high voltages
Solution Approach 1:
The patent changes the key parameter of transistor material composition based on operational voltage levels. During startup at high voltages, GaN transistors with lower parasitic capacitance are used, reducing energy loss. During normal operation, silicon transistors are used. This parameter change optimizes energy efficiency by matching transistor characteristics to voltage conditions.
Data Source
AI summary
An integrated driver applied to a voltage converter having a switched capacitor conversion circuit, the integrated driver including: a first die having a first-type power transistor; a second die including at least one second-type power transistor, where a withstand voltage of the first-type power transistor is higher than a withstand voltage of the second-type power transistor; and where the first die and the second die are coupled in series between a high potential terminal and a low potential terminal of the voltage converter, such that the first-type power transistor receives a high voltage signal.