Passgate Gate Driver Charge Injection for No-Overshoot Switching

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Solution Overview

Problem

Overshoot and undershoot voltages during switching in passgate switches can damage systems due to overvoltage stresses, primarily caused by external RLC components and mismatched capacitance between NMOS and PMOS transistors, posing challenges in maintaining efficient switching with wide-supply-voltage ranges and low-supply currents.

Innovation Solution

A gate driver control system with a Pass Gate Charge-Injector and Input/Output Voltage Sensing Timers that regulate the charging and discharging speeds of passgate switches to achieve a 'fast-start, slow-after' response, preventing overshoot and undershoot while adapting to wide-supply-voltage ranges without active current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If fast switching is implemented in passgate switches, then switching speed is improved, but voltage overshoot and undershoot occur causing system damage

Engineering Contradiction:

Improveswitching speedVSAvoidvoltage overshoot and undershoot

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The gate driver control circuit performs preliminary action by pre-charging or pre-discharging the gate of the passgate transistor before the actual switching event. This prepares the transistor to switch more gradually, preventing sudden current changes that cause voltage overshoot and undershoot. The circuit activates compensation transistors in advance to control the gate voltage transition profile.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the gate voltage parameters dynamically during switching. By adjusting the gate voltage rise/fall time, amplitude, and waveform shape through controlled charging/discharging paths, the transistor switching characteristics are modified to eliminate overshoot while maintaining fast switching. The compensation transistors modify the gate voltage parameters in real-time during the transition.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If external RLC components and mismatched capacitance are present, then passgate switching functionality is achieved, but voltage overshoot is generated

Engineering Contradiction:

Improvepassgate switching functionalityVSAvoidvoltage overshoot

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful effect of RLC components and capacitance mismatch into a beneficial control mechanism. By sensing the actual switching conditions and using feedback from the gate voltage, the control circuit adjusts the charging/discharging paths to compensate for the RLC effects. The compensation transistors are controlled to counteract the overshoot generated by the external RLC network, turning the problematic interaction into a controllable parameter.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If gate driver control is added to prevent overshoot, then voltage stability is improved, but device complexity increases

Engineering Contradiction:

Improvevoltage stabilityVSAvoidgate driver control circuit

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the overshoot compensation function with the existing gate driver control circuit. The compensation transistors are integrated into the gate driver structure, sharing common control nodes and power supplies. The same control logic that drives the main switching transistor also controls the compensation transistors, combining multiple functions into a unified circuit block rather than adding separate complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gate driver control circuit is designed with multi-functionality, serving both as the primary switching control and as an overshoot compensation mechanism. The compensation transistors can be activated or deactivated based on switching conditions, allowing the circuit to perform different functions using the same hardware resources. This universal design reduces overall system complexity compared to having separate dedicated compensation circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables fast switching with no-overshoot across wide-supply-voltage ranges, ensuring adaptability and low power consumption by controlling the switching states of passgate switches effectively.

Implementation Method 1

a Pass Gate Charge-Injector arranged to alter a charging speed and/or a discharging speed of an electrical charge at a gate of the PMOS and/or NMOS transistor

Methodology Applied

Scientific EffectElectrical charge movement: Conduction (electrical)

Data Source

PatentEP4589846A1A passgate switch gate-driver control for preventing no-overshoot when switching

Publication Date: 2025.07.23 NEXPERIA BV

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AI summary

A Passgate Gate-Driver Control system is proposed, including a Gate-Driver Control (110) and a passgate switch (106, 108). The passgate switch includes a P-channel Metal-Oxide-Semiconductor, PMOS, transistor and an N-channel Metal-Oxide-Semiconductor, NMOS, transistor. The Gate-Driver Control comprises a Pass Gate Charge-Injector (112) arranged to alter a charging speed and/or a discharging speed of an electrical charge at a gate of the PMOS and/or NMOS transistor.