Product Operating Status:
Operating voltage: DC12V. Testing USB playback. FM98.1 playback.
Product Testing Issues:
During testing, the product may restart and cannot revert to the original operating mode.
Accompanied by howling noise. (Only meets 30mA A grade)
Testing Standards and Grade Requirements:
200mA B grade, 100mA A grade,
60mA A grade, 30mA A grade.
After rectification, it meets the customer’s requirement of 200mA (this test reached A grade), 100mA A grade,60mA A grade, 30mA A grade.
Issue Analysis
High current interference is caused by ripple interference, which leads to various abnormalities in machine performance. Therefore, the main idea of rectification is to reduce ripple interference to meet standard requirements.
Rectification Measures: 1. PCB grounding. 2. Port filtering
1. PCB grounding
Due to insufficient grounding between the PCB and the shell, interference could not be quickly conducted to the shell, causing machine restarts and howling.
Conductive foam is added to the MCU and radio chip.
2. Port filtering
1) The machine’s USB has fast charging functionality, and the USB is powered separately from the external power supply, with the B+ of the port being independently powered.
2) Upon examining the PCB, it was found that the USB port and ACC port did not have effective filtering circuits.
Capacitors 104+102 are added to these two ports for grounding.
Our goal is to solve the most troublesome problems at the lowest cost.
Rectification Materials
2 pieces of 104 capacitors
2 pieces of 102 capacitors
2 pieces of conductive foam (10mm*10mm)
Shenzhen Jianyi Technology Co., Ltd., a professional electromagnetic compatibility (EMC) testing system integrator, provides professional measurement equipment for the manufacturing, research and development, and inspection of electronic products and automotive electronics; EMC testing equipment, RF testing equipment, general testing equipment for electronic products, and testing system integration solutions, including electromagnetic compatibility (EMC) testing laboratory turnkey projects with dark rooms and complete testing systems. Over the years, we have served various inspection institutions, enterprises, universities, and national defense sectors; covering automotive electronics, information technology, home appliances, industry, power, medical, lighting, military, aerospace, and other industries.
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