Adaptive Gate Voltage Control for Lower Switching Loss

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Solution Overview

Problem

Conventional switching power supplies experience significant losses due to excessively low gate on voltages, which prolong mode switching duration and hinder efficient operation of semiconductor switching devices.

Innovation Solution

A control circuit that detects the current operating condition of semiconductor switching devices and adjusts the gate on voltage to a level not higher than the gate allowable voltage, ensuring it is positively correlated with the operating condition to minimize losses and enhance switching performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a constant low gate on voltage is used to ensure reliability under extreme conditions, then breakdown is prevented, but mode switching duration increases and switching losses increase

Engineering Contradiction:
Improvebreakdown preventionVSAvoidswitching loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The gate on voltage is changed from a constant value to a dynamically adjustable value that adapts to different operating conditions. The control circuit monitors operating conditions and adjusts the gate on voltage in real-time, allowing the system to optimize between reliability and switching performance based on current operational state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gate on voltage parameter is changed from a fixed constant to a variable parameter that changes based on operating conditions. By adjusting this electrical parameter dynamically, the system achieves both reliable operation under extreme conditions and optimized switching performance under normal conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a constant low gate on voltage is used to ensure reliability under extreme conditions, then breakdown is prevented, but mode switching duration increases

Engineering Contradiction:
Improvebreakdown preventionVSAvoidmode switching duration
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The gate on voltage transitions from a static constant value to a dynamic variable that responds to operating conditions. This allows the switching duration to be optimized in real-time without compromising reliability, as the voltage adjusts to match the actual operational state of the semiconductor device.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gate on voltage parameter is modified from a fixed value to a condition-dependent variable. This parameter change enables the system to reduce mode switching duration when conditions permit while maintaining reliability constraints when operating under extreme conditions.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If a higher gate on voltage is used to shorten mode switching duration, then switching losses are reduced, but breakdown may occur under extreme conditions

Engineering Contradiction:
Improveswitching lossVSAvoidbreakdown risk
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The gate on voltage is transformed from a fixed high value to a condition-adjustable parameter. This allows the system to apply higher voltages when conditions allow (reducing switching losses) while automatically lowering the voltage when extreme conditions are detected (preventing breakdown).

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control circuit implements feedback by monitoring operating conditions and using this information to adjust the gate on voltage accordingly. This closed-loop control ensures that the gate voltage remains within safe limits under extreme conditions while maximizing switching performance under normal conditions.

Inventive Principle:
Principle #23Feedback

4Duration of action of moving object

If a higher gate on voltage is used to shorten mode switching duration, then switching losses are reduced, but switching frequency capability is limited by loss constraints

Engineering Contradiction:
Improvemode switching durationVSAvoidswitching loss
Core Design Contradiction:
Duration of action of moving objectVSLoss of energy

Solution Approach 1:

The gate on voltage becomes a dynamic parameter that can be adjusted to achieve optimal switching duration without incurring excessive losses. This dynamic adjustment enables the system to operate at higher frequencies by reducing switching duration through voltage optimization, thereby reducing overall switching losses.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3937361B1Control circuit, voltage source circuit, drive device, and drive method
Publication Date: 2024.03.20 HUAWEI DIGITAL POWER TECH CO LTD
  • EP3937361B1 patent drawingFigure 1~2
  • EP3937361B1 patent drawingFigure 3~4
  • EP3937361B1 patent drawingFigure 5~6

AI summary

Embodiments of this application disclose a control circuit, including: a detection module, configured to detect an operating condition of a semiconductor switching device; a determining module, configured to determine a gate allowable voltage of the semiconductor switching device based on the operating condition; and an output module, configured to output a control signal to a driving power supply circuit of the semiconductor switching device based on the gate allowable voltage, to control the driving power supply circuit to provide a gate on voltage that is not higher than the gate allowable voltage and that is positively correlated with the gate allowable voltage for the semiconductor switching device. When the operating condition of the semiconductor switching device becomes better, the gate allowable voltage of the semiconductor switching device is increased. In this case, the control circuit can control the driving power supply circuit to provide an increased gate on voltage that is not higher than the gate allowable voltage for the semiconductor switching device, which is beneficial to shortening mode switching duration of the semiconductor switching device for switching between a full-on mode and a full-off mode while ensuring reliability of the semiconductor switching device, thereby reducing a loss of a switching power supply.