Switching Power Supply Overshooting Protection Circuit

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Solution Overview

Problem

Switching power supply circuits face instability due to rapid changes in load resistance, leading to transient overshooting of output voltage beyond maximum allowable limits, causing circuit instability.

Innovation Solution

Incorporation of an overshooting protection module with a switching unit and detecting unit that monitors output signals and adjusts PWM signal generation to prevent overshooting by keeping the PWM signal at a low level when the output signal exceeds a threshold voltage, thereby preventing the output signal from exceeding the maximum allowable voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the load resistance changes rapidly, then the power supply can adapt to different load conditions, but the output voltage may overshoot and exceed maximum allowable voltage

Engineering Contradiction:

Improveload adaptationVSAvoidoutput voltage stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The overshooting protection module performs preliminary detection of output voltage before overshooting occurs. When the output voltage approaches the threshold voltage, the module preemptively adjusts the PWM signal to prevent overshooting, rather than reacting after overshooting has already occurred.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection module continuously monitors the output voltage and uses this feedback to control the PWM signal generator. When the output voltage reaches the threshold voltage, the feedback mechanism triggers the switching unit to disable the PWM signal generator, creating a closed-loop control system that prevents overshooting.

Inventive Principle:

Principle #23Feedback

2Productivity

If the PWM signal generator continues operating during load changes, then power delivery is maintained, but output voltage overshooting occurs

Engineering Contradiction:

Improvepower delivery continuityVSAvoidvoltage overshooting

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The overshooting protection module acts as an intermediary between the PWM signal generator and the power output stage. It monitors the output voltage and controls the PWM signal generator's operation, enabling it to disable the PWM signal when necessary to prevent overshooting while allowing continuous operation during normal conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protection module disables the PWM signal generator in advance when the output voltage approaches the threshold, preventing overshooting before it occurs. This preliminary action ensures power delivery continuity by only interrupting operation when absolutely necessary.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9240716B2Switching power supply circuit

Publication Date: 2016.01.19 ASUSTEK COMPUTER INC

AI summary

A switching power supply circuit is disclosed in an embodiment. The switching power supply circuit includes a power output stage, a pulse width modulation (PWM) signal generator, a compensation module, and a overshooting protection module. The power output stage is used for generating an output signal to drive a load device. The PWM signal generator generates a pulse width modulation (PWM) signal which is used for controlling the power output stage. The compensation module is used for generating a compensation signal to the PWM signal generator according to the output signal. The overshooting protection module receives the output signal to enable or disable the PWM signal generator.