Integrated Semiconductor Device for Synchronous Switching Converter Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Step-down synchronous switching converters face inefficiencies due to high forward voltage and slow reverse recovery of the body diode in low-side synchronous switches, leading to significant dynamic losses.
Innovation Solution
An integrated semiconductor device is introduced, comprising a first MOSFET with a body diode and a second semiconductor component, either a diode or a MOSFET, coupled in parallel, where the forward voltage of the second component is lower than the body diode, and cells are distributed unevenly based on current flow to optimize current transmission and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a body diode is used in the low-side synchronous switch, then the switch can provide a current path when the high-side switch is off, but the high forward voltage and slow reverse recovery of the body diode cause large turn-on losses and dynamic losses
Solution Approach 1:
The patent combines a first semiconductor component (MOSFET with body diode) and a second semiconductor component (diode or MOSFET) in parallel to form an integrated synchronous switch. The second component is specifically designed to handle the reverse recovery phase with lower losses, while the first component handles the main current conduction, thereby reducing overall turn-on and dynamic losses while maintaining reliable current path provision.
Solution Approach 2:
The patent applies local quality by making the second semiconductor component have different electrical characteristics than the first component. Specifically, the second component has lower forward voltage (if a diode) or lower threshold voltage (if a MOSFET) to optimize performance in specific operating conditions, particularly during reverse recovery and low-voltage operation, thereby reducing energy losses in critical phases.
2Ease of manufacture
If cells of the second semiconductor component are distributed uniformly, then the structure is simple to manufacture, but the current distribution is not optimized leading to suboptimal loss reduction
Solution Approach 1:
The patent implements non-uniform distribution of cells in the second semiconductor component based on the actual current flow distribution through the integrated device. Areas with higher current density have more cells, while areas with lower current density have fewer cells. This optimized spatial arrangement reduces dynamic losses by ensuring that the second component effectively handles current in regions where it flows most, while maintaining manufacturability through a systematic distribution pattern.
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 the efficiency of the synchronous switching converter by minimizing turn-on losses and dynamic losses, resulting in improved overall performance.
Implementation Method 1
the second semiconductor component comprises a diode with an anode and a cathode, wherein the anode of the diode is coupled to the source of the first MOSFET, the cathode of the diode is coupled to the drain of the first MOSFET, wherein a forward voltage of the diode is lower than a forward voltage of the body diode in the first MOSFET
Implementation Method 2
the second semiconductor component comprises a second MOSFET, the second MOSFET has a source, a drain and a gate, wherein the drain of the second MOSFET in the second semiconductor component is coupled to the drain of the first MOSFET, both the source and the gate of the second are coupled to the source of the first MOSFET, and a threshold voltage of the second MOSFET is lower than a threshold voltage of the first MOSFET
Implementation Method 3
an inductor, configured to store energy when the power switch is on and release energy when the power switch is off
Data Source
AI summary
A synchronous switching converter has an integrated semiconductor device. The integrated semiconductor device has a first semiconductor component and a second semiconductor component coupled in parallel. The first semiconductor component has MOSFET cells with body diodes, and the second semiconductor component has diode cells or MOSFET cells with a low forward voltage. Cells of the second semiconductor component distribute among the first semiconductor component unevenly according to a distribution of a current flowing through the integrated semiconductor device.