Power Switch Deactivation Driver for Loss and Ringing Control

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Solution Overview

Problem

Switching power supplies experience inefficiencies due to switching losses and potential damage from excessive ringing of current during power switch deactivation, which are inversely proportional to the activation/deactivation speed.

Innovation Solution

A power switch deactivation driver controls the amplitude of the control voltage based on the voltage difference between the power rail and the switching terminal, implementing a variable rate of deactivation through a sense resistor and current mirror transistors to optimize efficiency and reduce ringing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the power switch deactivation speed is increased to reduce switching losses, then switching efficiency is improved, but current ringing and potential damage occur

Engineering Contradiction:

Improveswitching lossesVSAvoidcurrent ringing

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic deactivation control by adjusting the control voltage amplitude based on real-time voltage difference between power rail and switching terminal. The deactivation driver modifies the control voltage to transition the power switch from full activation to full deactivation in stages, adapting the deactivation rate to the instantaneous operating conditions rather than using a fixed speed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the control voltage parameter during deactivation to optimize performance. Specifically, the control voltage amplitude is adjusted based on the voltage difference measurement, allowing the system to transition from rapid deactivation (when voltage difference is large) to slower deactivation (when voltage difference approaches zero), thereby minimizing both switching losses and current ringing.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the power switch deactivation speed is increased to improve productivity, then switching frequency is improved, but reliability deteriorates due to excessive ringing

Engineering Contradiction:

Improveswitching frequencyVSAvoidswitch durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent employs feedback control by continuously monitoring the voltage difference between the power rail and switching terminal during deactivation. This feedback signal is used by the deactivation driver to dynamically adjust the control voltage amplitude, creating a closed-loop control system that automatically optimizes deactivation speed to prevent harmful ringing while maintaining high switching frequency.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies beforehand cushioning by preparing the control voltage adjustment in advance during the deactivation process. As the voltage difference decreases and approaches the critical region where ringing occurs, the system proactively reduces the control voltage amplitude to cushion against potential ringing damage before it occurs, rather than reacting after the damage has happened.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If a fixed deactivation rate is used to simplify device complexity, then control circuit simplicity is improved, but switching losses and ringing cannot be optimized

Engineering Contradiction:

Improvecontrol circuit complexityVSAvoidswitching losses

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent segments the deactivation process into distinct phases based on voltage difference thresholds. The deactivation driver divides the transition from activation to full deactivation into stages: rapid deactivation phase (when voltage difference is large) and controlled deactivation phase (when voltage difference is small). This segmentation allows the system to apply different control strategies to different phases, optimizing performance without requiring overly complex continuous control.

Inventive Principle:

Principle #1Segmentation

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

The variable rate of deactivation minimizes switching losses and mitigates current ringing, enhancing the efficiency and reliability of power supply systems by balancing rapid and slow deactivation stages.

Implementation Method 1

a sense resistor coupled to the power rail to conduct a sense current having an amplitude based on a voltage difference between the power rail and the switching terminal

Methodology Applied

Scientific EffectOhm's Law: Ohm's Law

Implementation Method 2

a first current mirror transistor comprising a first terminal coupled to the first sense resistor and a second terminal coupled to the other of the power rail or the switching terminal

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentUS20250286448A1Power switch deactivation driver

Publication Date: 2025.09.11 TEXAS INSTRUMENTS INC

AI summary

One example includes a power supply system. The system includes a power switch configured to activate via a control voltage responsive to a first state of an activation signal to conduct current from a power rail to a switching terminal. The system further includes a power switch deactivation driver configured to control an amplitude of the control voltage responsive to a second state of the activation signal based on a voltage difference between the power rail and the switching terminal to provide for a variable rate of deactivation of the power switch.