ESD Protection Circuit for High Side Driver
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Solution Overview
Problem
High side driver circuits face difficulties in meeting the C4B certification for electrostatic discharge (ESD) protection, particularly in withstanding ESD stresses of ±500V at non-corner pins and ±750V at corner pins, due to existing ESD protection limitations.
Innovation Solution
A circuit design incorporating a power MOSFET, a sense MOSFET, a resistor, a Zener diode, and a clamp diode, where the Zener diode provides a fast derivative path for electrostatic charges and the resistor limits peak current, while the clamp diode handles overvoltage, ensuring effective ESD protection by controlling voltage and current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing ESD protection structures are used in high side driver circuits, then the circuit can operate normally, but it cannot withstand ESD stresses of ±500V at non-corner pins and ±750V at corner pins to meet C4B certification
Solution Approach 1:
A dedicated ESD protection circuit is introduced as an intermediary component between the high side driver circuit and the ESD stress source. This protection circuit includes protection transistors positioned at strategic locations (corner and non-corner pins) to intercept and divert ESD current away from sensitive circuit nodes, thereby enabling the circuit to meet C4B certification requirements without fundamental redesign of the driver architecture.
Solution Approach 2:
The ESD protection is segmented into multiple discrete protection elements distributed at different locations within the circuit - specifically at corner pins and non-corner pins. Each segment handles localized ESD events independently, allowing the overall circuit to withstand distributed ESD stresses while maintaining normal operation of individual functional blocks.
2Reliability
If ESD protection is added to high side driver circuit, then ESD withstand capability improves, but existing protection limitations prevent meeting C4B certification
Solution Approach 1:
The protection circuit is designed to activate preemptively upon detection of ESD stress conditions. Protection transistors are biased and positioned to immediately conduct when ESD voltage exceeds threshold levels, creating a low-impedance discharge path before the ESD event can damage sensitive nodes. This preliminary protective action enables the circuit to survive ±500V and ±750V stress levels required for C4B certification.
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 proposed circuit effectively protects high side driver circuits from ESD events by limiting peak current and overvoltage, enhancing their ability to withstand ESD stresses and meet stringent certification requirements.
Implementation Method 1
a zener diode having an anode terminal coupled to the source terminal of the sense MOSFET device and a cathode terminal coupled to the gate terminal of the sense MOSFET device
Implementation Method 2
a clamp diode having an anode terminal coupled to the source terminal of the sense MOSFET device and a cathode terminal coupled to the gate terminal of the power MOSFET device
Data Source
AI summary
Electrostatic discharge (ESD) protection is provided by a circuit including a resistor having a first terminal and a second terminal, a zener diode having a cathode terminal directly connected to said first terminal and an anode terminal directly connected to a third terminal, and a clamp diode having a cathode terminal directly connected to said second terminal and an anode terminal directly connected to said third terminal.