Diode-Built-In IGBT Feedback Control for Forward Loss Reduction
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Solution Overview
Problem
Conventional semiconductor devices with built-in diodes experience increased forward losses due to interference between diode and IGBT actions, leading to higher forward voltages and losses, particularly in inverter circuits and DC-DC converters, where the diode and IGBT elements share common electrodes, causing inefficiencies and requiring additional circuitry for current sensing and noise resistance.
Innovation Solution
A semiconductor device with a diode-built-in IGBT or DMOS structure incorporates a feedback unit that detects current through the diode and adjusts the driving signal for the IGBT, preventing interference and optimizing diode operation by controlling the gate signal based on diode current thresholds, thereby reducing forward losses and enhancing noise resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the diode elements and IGBT elements share common electrodes, then the device structure is simplified, but the forward voltage of the diode increases and forward loss increases
Solution Approach 1:
The patent divides the semiconductor substrate into multiple regions: a first region containing IGBT elements, a second region containing diode elements, and a third diode-only region. This segmentation allows the diode elements to operate independently without interference from IGBT gate signals, reducing forward voltage and forward loss while maintaining the integrated structure benefit.
2Loss of energy
If a diode-only region is formed separately, then the forward loss is reduced, but the chip size increases
Solution Approach 1:
The patent merges the diode-only region with the existing IGBT and diode element regions on the same semiconductor substrate, creating an integrated structure where all three regions share common processing and packaging infrastructure. This approach reduces overall chip size compared to separate discrete implementations while maintaining the low forward loss benefit of the diode-only region.
3Measurement precision
If current transformer is added for current sensing, then the current detection precision is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the current sensing function from external components (current transformers) and implements it directly within the semiconductor device using sense resistors integrated into the substrate. This extraction eliminates the need for external current transformers, reducing device complexity and circuit scale while maintaining adequate current detection precision through the integrated sensing mechanism.
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate; a diode-built-in insulated-gate bipolar transistor having an insulated-gate bipolar transistor and a diode, which are disposed in the substrate, wherein the insulated-gate bipolar transistor includes a gate, and is driven with a driving signal input into the gate; and a feedback unit for detecting current passing through the diode. The driving signal is input from an external unit into the feedback unit. The feedback unit passes the driving signal to the gate of the insulated-gate bipolar transistor when the feedback unit detects no current through the diode, and the feedback unit stops passing the driving signal to the gate of the insulated-gate bipolar transistor when the feedback unit detects the current through the diode.