Shutter Circuit for Multi-Channel Converter Noise Isolation

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Solution Overview

Problem

Switching converters experience misoperation due to switching noise interference between channels, causing premature turning off of transistors and incorrect timing of switching elements.

Innovation Solution

A shutter circuit is introduced to detect switching information across channels and generate blanking signals to block current sensors during switching events, preventing the detection of switching noise and thus eliminating mutual interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple channels share common power line and ground line, then device integration is improved, but switching noise interference between channels increases

Engineering Contradiction:

Improvedevice integrationVSAvoidswitching noise interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A shutter circuit is introduced as an intermediary component that detects switching events in one channel and generates blanking signals to mask switching noise in other channels. The shutter circuit acts as a mediator between the switching elements and current sensors, preventing noise propagation through the shared power and ground lines while maintaining channel isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If current sensors continuously monitor output current, then control precision is improved, but susceptibility to switching noise increases

Engineering Contradiction:

Improvecontrol precisionVSAvoidswitching noise susceptibility

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The shutter circuit implements periodic blanking action by generating mask signals during detected switching events. When a switching event is detected in any channel, the shutter circuit periodically blocks the current sensor outputs during the switching noise duration, allowing continuous monitoring while eliminating noise susceptibility during critical switching periods.

Inventive Principle:

Principle #19Periodic action

3Productivity

If switching elements operate at high speed, then productivity is improved, but switching noise magnitude increases

Engineering Contradiction:

Improveswitching speedVSAvoidswitching noise magnitude

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The shutter circuit converts the harmful switching noise into a detectable switching event signal. By detecting the edges of switching waveforms and using these events to trigger blanking signals, the circuit transforms the noise-generating switching action into a useful control mechanism that automatically masks the noise during critical periods, turning the harmful high-speed switching into a beneficial self-regulating system.

Inventive Principle:

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

Data Source

PatentUS7956585B2Mutual blanking for a multi-channel converter

Publication Date: 2011.06.07 RICHTEK TECH

AI summary

A shutter circuit is provided for a multi-channel converter to blank the switching noise produced by the switching of the converter. The shutter circuit monitors the switching of the switches in the output stages of the converter, and when one channel performs switching, the shutter circuit will send a signal to other channels to block the current sensors thereof. The current sensors are so blocked for a period not to sense the switching noise. The mutual interference between the channels due to the switching noise of the converter is eliminated.