Semiconductor Power Supply Clamp Circuit for Overvoltage Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Semiconductor devices face issues with internal power supply voltage fluctuations due to changes in external power supply voltage, leading to potential overvoltage problems and reduced withstand voltage in circuit groups.

Innovation Solution

Incorporating a clamp circuit that adjusts the control electrode voltage of the drive transistor to decrease drive current when the internal power supply voltage rises, allowing for quicker stabilization and preventing overvoltage issues, in conjunction with a feedback control system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feedback control by error amplifier is used to regulate internal power supply voltage, then voltage regulation is achieved, but response speed is slow when external power supply voltage fluctuates

Engineering Contradiction:

Improvevoltage regulationVSAvoidresponse speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The clamp circuit is configured to activate before the error amplifier can respond to voltage fluctuations. When the internal power supply voltage rises above a predetermined threshold, the clamp circuit immediately clamps the control electrode voltage of the drive transistor, reducing drive current and preventing excessive voltage rise before the feedback loop can react.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The clamp circuit applies a counteracting action by clamping the control electrode voltage to reduce drive current when voltage rise is detected, thereby preemptively opposing the harmful effect of excessive voltage increase before it can cause damage to circuit components.

Inventive Principle:

Principle #9Preliminary anti-action

2Power

If drive current increases due to external power supply voltage fluctuation, then internal power supply voltage rises, but this causes overvoltage problems in circuit groups

Engineering Contradiction:

Improvedrive currentVSAvoidovervoltage

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The clamp circuit monitors the internal power supply voltage and provides immediate feedback action by clamping the control electrode voltage when the internal voltage exceeds a predetermined threshold. This creates a fast-acting feedback mechanism that directly counteracts the harmful effect of excessive drive current caused by external power supply voltage fluctuations.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8994410B2Semiconductor device with power supply circuit

Publication Date: 2015.03.31 RENESAS ELECTRONICS CORP

AI summary

The present invention is directed to prevent occurrence of a problem on a withstand voltage in a circuit group which receives supply of an internal power supply voltage. An error amplifier outputs a control voltage obtained by amplifying a difference voltage between a reference voltage and a divided voltage obtained by dividing an internal power supply voltage to an output node. A drive transistor supplies a drive current according to the control voltage of the output node of the error amplifier from an external power supply line to an internal power supply line. When the divided voltage exceeds a predetermined voltage, a clamp circuit changes the control voltage in the direction of decreasing the drive current.