Leiditech EMC Expert Team Rectification Cases
A.Chip-level EMC case presentation:
1. A high-voltage ESD protection scheme using a multi-state MOS to assist in triggering a SCR
2. Leakage suppression and electrostatic protection techniques in the chip transmission pressure circuit
B.Consumer Electronics
1. Problem Description: Contact with 10KV, electrostatic discharge to USB ID, causing screen not to light up.
Failure Cause: Electrostatic charge passed through the 1K resistor of the USB ID, and then discharged to the adjacent 0R resistor. The 0R resistor supplies power to the screen IC, causing the screen IC to be damaged.
Optimization Plan:
Plan One: Add TVS diodes to the USB ID;
Plan Two: Move the 0R resistor away, keeping it far from the 1K resistor.
2. Problem Description: After the product was launched, there was a problem of system freeze.
Failure Cause: Antenna signal coupled to the T card signal line. The T card signal line inside the CPU and the CPU reset line overlapped, causing system freeze.
Improvement Plan: Reduce the RF transmission power and optimize the internal wiring of the chip simultaneously.
3. Problem Description: A handheld device, air 12KV caused the single unit of the SIM card to be damaged.
Failure Cause: Electrostatic charge entered the SIM card slot gap and pressed into the material hole of the card tray, resulting in secondary discharge, causing the single unit of the SIM card to be damaged.
Optimization Plan: Extend the metal frame outward beyond the material hole.
C.Large-scale power supply，new energy battery；
D.Automotive-grade electronic equipment;
E.Electric power industry；
F.Military aerospace products;
G.Large medical appliances;
EMC forward design and rectification, Leimao has dictionary-like accumulation, systematic EMC diagnostic analysis tools and methods, and is good at solving all kinds of difficult problems.
The products of Shanghai Leiditech Electronic Technology Co., Ltd. meet the relevant national testing standards and requirements, as well as international standards such as IEC.FCC, and have obtained UL, VDE, ROHS, REACH and other series of certifications. Leimao products can meet the requirements of high-standard lightning protection, overvoltage protection and overcurrent protection, thereby improving the service life of the core components of the circuit, and enhancing the flexibility and scalability of the end product.
