Semiconductor Device with Segmented Die Pads for Heat and Noise Management
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Solution Overview
Problem
Semiconductor devices driving three-phase motors face challenges in improving radiation performance, reducing noise and parasitic capacitance, and preventing false operations due to the design of high-side and low-side switching elements, where enlarging drain leads for better heat radiation increases noise and capacitance, and insulating the low-side drain lead from the heat sink worsens thermal resistance.
Innovation Solution
The semiconductor device design includes die pads connected to opposite ends of a DC power source, with high-side and low-side switching elements mounted on these pads, where the high-side elements have their drain electrodes connected to a heat sink for efficient heat radiation and the low-side elements have their drain electrodes connected to the output terminals, minimizing parasitic capacitance and noise by maintaining equal distances between switching elements and using conductive materials for improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the drain lead of the low-side power MOSFET is enlarged to improve heat radiation performance, then heat radiation is improved, but noise and parasitic capacitance increase
Solution Approach 1:
The patent divides the heat dissipation function into two separate paths: one for the high-side MOSFET through its drain lead to the heat sink, and another for the low-side MOSFET through its source lead to the heat sink. This segmentation allows each switching element to have optimized lead configurations without interfering with each other, enabling the low-side drain lead to remain short while still achieving effective heat dissipation through the alternative source lead path.
Solution Approach 2:
The patent inverts the conventional heat dissipation approach for the low-side MOSFET by routing heat through the source lead instead of the drain lead. Conventionally, heat is dissipated through the drain lead to the heat sink, but this patent uses the source lead as the primary heat dissipation path, connecting it to the heat sink, thereby avoiding the noise and parasitic capacitance issues associated with enlarging the drain lead.
2Object-generated harmful factors
If the low-side drain lead is insulated from the heat sink to suppress noise, then noise is reduced, but thermal resistance increases and radiation performance deteriorates
Solution Approach 1:
The patent segments the heat dissipation function between the drain lead and source lead of the low-side MOSFET. The drain lead is kept short and insulated for signal integrity, while the source lead is specifically designed as a heat dissipation path with low thermal resistance to the heat sink. This segmentation allows noise suppression in the drain lead while maintaining effective thermal coupling through the source lead.
Solution Approach 2:
The source lead of the low-side MOSFET acts as an intermediary for heat dissipation, transferring thermal energy from the MOSFET to the heat sink without being affected by electrical noise concerns. This intermediary path separates the electrical signal path (drain lead) from the thermal management path (source lead), allowing optimized performance in both domains.
3Temperature
If the drain lead is enlarged to improve radiation performance, then heat radiation is improved, but operation speed slows down due to increased parasitic capacitance
Solution Approach 1:
The patent segments the heat dissipation function into separate paths for high-side and low-side MOSFETs, with the low-side MOSFET using its source lead for heat dissipation. This segmentation allows the drain lead to remain short and thin for fast switching performance, while the source lead provides the thermal management function, thereby maintaining high operation speed without compromising heat radiation performance.
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 configuration enhances heat radiation performance, reduces noise and parasitic capacitance, and accelerates operation speed by effectively managing heat and electrical potential fluctuations, thereby improving the reliability and efficiency of the semiconductor device.
Implementation Method 1
The drain lead is installed on a heat sink, and effectively radiates heat generated in response to the operation of the power MOSFET
Implementation Method 2
effectively radiates heat generated in response to the operation of the power MOSFET
Data Source
AI summary
A semiconductor devices includes a first die pad having the conductivity connected to one end of a DC power source, a second die pad having the conductivity connected to the other end of the DC power source, a first switching element provided on the first die pad, receiving DC power from the DC power source via the first die pad, and having a terminal opposite to the first die pad connected to a first output terminal, and a second switching element provided on the second die pad, receiving the DC power from the DC power source via the second die pad, and connected to the first output terminal, and having a terminal opposite to the second die pad.