Self-Powered MOSFET Gate Control for Low-Loss State Switching

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Solution Overview

Problem

Existing transistor control circuits suffer from inefficiencies in current management, particularly during state changes, leading to increased current losses and a need for self-powered solutions.

Innovation Solution

A self-powered control circuit for N-channel MOS transistors that utilizes a control unit and driver circuit to manage voltages efficiently, incorporating power supply circuits, voltage measurement, and comparison circuits to optimize transistor operation, reducing current consumption by detecting the end of the conduction cycle early.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional transistor control circuits are used, then the transistor can be controlled to switch states, but current losses increase during state changes

Engineering Contradiction:
Improvecurrent losses during state changesVSAvoidtransistor switching efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The control circuit proactively manages the transition process by detecting voltage conditions and applying appropriate control signals before the transistor fully switches states. This preliminary action prevents excessive current losses by controlling the parasitic diode conduction during the transition phase, rather than reactively addressing the problem after it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control circuit incorporates feedback mechanisms that monitor the voltage between drain and source terminals, as well as the control terminal voltage. Based on this feedback, the circuit dynamically adjusts the control signals to optimize switching behavior and minimize current losses during state transitions.

Inventive Principle:
Principle #23Feedback

2Use of energy by stationary object

If external power supply is provided to control circuit, then control functionality is achieved, but power consumption increases

Engineering Contradiction:
Improvecontrol circuit power consumptionVSAvoidself-powered capability
Core Design Contradiction:
Use of energy by stationary objectVSEase of operation

Solution Approach 1:

The control circuit is designed to be self-powered by utilizing the voltage already present between the drain and source terminals of the transistor, as well as the control terminal voltage. This eliminates the need for separate external power supply connections, reducing overall system complexity and power consumption while maintaining full control functionality.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control circuit performs multiple functions using the same voltage sources that are already present in the transistor operation. It uses the drain-source voltage and control terminal voltage both for powering the control circuitry and for detecting transistor state, thereby eliminating dedicated power supply requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If control voltage is continuously applied, then transistor state is maintained, but current consumption increases

Engineering Contradiction:
Improvecurrent consumptionVSAvoidtransistor state control
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

Instead of continuously applying control voltage, the control circuit uses periodic detection of voltage conditions and applies control signals only when needed to maintain the desired transistor state. This reduces current consumption while ensuring reliable state maintenance through timely intervention.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control circuit dynamically changes the control voltage parameters based on the detected transistor state and operating conditions. By adjusting the control voltage level and timing according to actual needs, the circuit maintains reliable transistor control while minimizing current consumption during different operational phases.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4346077B1Controlling a transistor
Publication Date: 2025.10.29 STMICROELECTRONICS (TOURS) SAS
  • EP4346077B1 patent drawingFigure 1
  • EP4346077B1 patent drawingFigure 2~3
  • EP4346077B1 patent drawingFigure 4

AI summary

This description relates to a method for controlling an N-channel MOS transistor, in which: - when the first voltage (VDS4) is less than a third voltage (VTHON4), a fourth control voltage (VGS4) of said transistor is greater than a fifth threshold voltage of said transistor; - when the first voltage (VDS4) is greater than the second voltage (Reg_Vthoff4), the fourth control voltage (VGS4) is less than the fifth voltage, in which said second voltage (Reg_Vthoff4) is equal to: - a first constant value (Ref_Vthoff5) between a first instant (t51) and a second instant (t52); - a second variable value, between the second instant (t52) and a third instant (t55), the second value being equal to the sum of the first voltage (VDS4) and a sixth positive voltage, the third instant (t55) corresponding to the instant when the first voltage (VDS4) reverses.