SoC Power Pin Protection Against ESD and Reverse Connection
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Solution Overview
Problem
System on Chip (SOC) devices are prone to damage from static electricity and reverse connection of external power supplies, leading to potential burning due to excessive current without current limiting devices.
Innovation Solution
Incorporating an anti-static unit and an anti-reverse connection unit between the power supply pin and ground pin, utilizing field effect transistors and diodes to provide ESD protection and prevent excessive current flow when the external power supply is reversely connected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anti-static unit is connected between power supply pin and ground pin, then ESD protection is provided, but reverse connection causes excessive current flow that can burn the SOC
Solution Approach 1:
An anti-reverse connection unit is introduced as an intermediary component between the anti-static unit and the external power supply. This unit acts as a mediator that blocks harmful reverse current while allowing normal forward current flow, thus protecting the SOC from both ESD and reverse connection damage without compromising the ESD protection function.
Solution Approach 2:
The anti-reverse connection unit is designed to preemptively block reverse current before it can reach the anti-static unit and cause damage. By detecting and preventing reverse connection in advance, the system avoids the harmful effects of excessive current flow while maintaining normal operation during correct power supply connection.
2Reliability
If the anti-reverse connection unit is added to prevent reverse connection damage, then protection against excessive current is improved, but the device complexity increases
Solution Approach 1:
The anti-reverse connection unit is designed to perform multiple protective functions simultaneously: it prevents reverse connection damage, limits excessive current flow, and works in conjunction with the anti-static unit to provide comprehensive protection. This multi-functionality reduces the need for separate protection circuits, thereby minimizing the increase in device complexity while maximizing protection capabilities.
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
Effectively conducts static electricity and cuts off current when the power supply is reversely connected, protecting the SOC and external power supply from damage.
Implementation Method 1
the anti-static unit performs ESD protection of the power supply pin through the conducted anti-static unit
Implementation Method 2
the PN junction is used to form a first diode between the first source and drain and the base of the first field effect transistor, and to form a second diode between the second source and drain and the base of the first field effect transistor
Data Source
AI summary
The present invention discloses a System on Chip, which includes a power supply pin, a ground pin, an anti-static unit and an anti-reverse connection unit, wherein the anti-static unit is connected between the power supply pin and the ground pin through the anti-reverse connection unit, the power supply pin and the ground pin of the System on Chip are connected to an external power supply; wherein, when the System on Chip is in normal operation, the anti-static unit performs ESD protection of the power supply pin through the conducted anti-static unit; whereas when the external power supply is reversely connected between the power supply pin and the ground pin of the System on Chip, the anti-reverse connection unit is cut off to prevent the reversely connected external power supply from directly connecting anode with cathode of the external power supply through the anti-static unit.