GaN Cascode Power Switch Integration for Fewer High-Voltage Dies
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Solution Overview
Problem
Current power conversion devices designed for high voltage applications require multiple dies due to the need for separate integration of power switches with high and low withstand voltage capabilities, leading to increased size and complexity.
Innovation Solution
Integrate a power switch and a cascode switch in a single die, where the power switch is implemented by a depletion-type GaN field-effect transistor and the cascode switch by an enhancement-type field-effect transistor, with the control circuit integrated in the same die, while the power switch is in a separate die with higher withstand voltage capability, reducing the number of dies needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power switch and control circuit are integrated in separate dies to meet high voltage requirements, then the withstand voltage capability is improved, but the number of dies increases and the device size becomes larger
Solution Approach 1:
The patent merges the control circuit and cascode switch into a single first die, while the power switch is integrated in a separate second die. This selective merging reduces the total number of dies from three to two, while still maintaining the necessary separation between high-voltage and low-voltage components. The control circuit and cascode switch, which operate at lower voltages, can be safely integrated together, reducing device complexity without compromising the high-voltage capability provided by the separate power switch die.
2Reliability
If three dies from different processes are used to implement the power switch, cascode switch, and control circuit, then the high voltage capability is achieved, but the device size increases due to multiple bonding wires
Solution Approach 1:
The patent combines the control circuit and cascode switch into a single first die, reducing the total die count from three to two. This integration eliminates the need for additional bonding wires between separate packages, thereby reducing the overall device footprint. The high-voltage capability is maintained because the power switch remains in a separate second die designed for high-voltage operation, while the integrated first die handles control and cascode functions at lower voltages.
Solution Approach 2:
The patent segments the device into two functional parts: a first die containing the control circuit and cascode switch, and a second die containing the high-voltage power switch. This segmentation allows each die to be optimized for its specific voltage requirements while reducing the total number of components. The segmentation strategy maintains high-voltage capability in the power switch die while minimizing the overall device size through integration of lower-voltage components in the first die.
3Reliability
If the power switch is implemented by a depletion-type GaN field-effect transistor for high voltage applications, then the withstand voltage capability is improved, but another switch is needed to control the power switch, increasing the number of dies
Solution Approach 1:
The patent merges the control circuit and cascode switch into a single first die, reducing the total die count from three to two. The depletion-type GaN power switch in the second die maintains high-voltage capability, while the integrated cascode switch and control circuit in the first die provide the necessary control functions. This merging eliminates the need for a separate third die for the control circuit, reducing device complexity while preserving the high-voltage performance of the GaN power switch.
Data Source
AI summary
A power conversion device is provided. The power conversion device includes a power switch circuit and a control circuit. The power switch circuit includes a power switch and a cascode switch. The power switch is implemented by a depletion-type gallium nitride (GaN) field-effect transistor. A first terminal of the power switch is coupled to a high-voltage terminal of the power conversion device. A first terminal of the cascode switch is coupled to a second terminal of the power switch. The control circuit is coupled to the power switch circuit. The control circuit and the cascode switch are integrated in a first die. The power switch is integrated in a second die. A withstand voltage capability of the second die is higher than a withstand voltage capability of the first die.