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PCBA function test guide

09/11/2023 在： /通过：

pcba Functional testing, which is performed to ensure that the product meets the design requirements both in terms of product description, user plans and operating programs, is performed according to the characteristics of the product description, user plans and operating programs. Functional testing ensures that the program works properly, tests the software against functional requirements, and tests all features and functions of the system to ensure that it meets the requirements and specifications.

Functional testing is also known as black box testing or data driven testing because only the various functions need to be tested one by one from the software product interface, the test case architecture based on written requirements, and the evaluation of the input data between the expected results and the actual results one by one, not the internal structure and code of the software.

PCBA functional testing will cover both hardware and software. The customer must send the test plan to the manufacturer to guide the test engineers. You need to list the behaviors and results (e.g., if you press, for example, button one, the green light comes on).

Why need Functional Testing

The purpose of PCBA functional testing is to ensure the quality of the product, improve the product qualification rate, improve the production process and get a better user experience. Functional testing can gain these following benefits:

·By simulating the operating environment for the PCB assembly under test, functional testing minimizes the cost for the customer. It is not necessary to provide the real and expensive testing equipment.

·It helps to avoid expensive system tests that often save the customer time and financial resources.

·It is possible to test 50-100% of the product before shipping, thereby minimizing the customer’s time and effort to test and debug the PCB assembly.

·It is possible for skilled professionals to extract the maximum productivity with a functional test, making this the most effective testing apart from a full system test.

·Along with ICT and flying probe tests, functional testing can make the PCB assembly error free and more robust.

PCBA function test method

1. Manual Test Fixture

Manual test fixtures use baking paint and acrylic pinboard output PCB input/output and power supply, and manually simulate input/output. The results are confirmed by the tester.

Due to high labor costs and low efficiency, manual testing is gradually replaced by manual test fixtures, which are only part of the test, but less demanding and less costly for manual participation.

2.MCU control function test

Make the fixture lock or pneumatic fixture and pull out the probe. Then connect the input/output power supply to the microcontroller circuit so that the microcontroller can run the test program and automatically measure the analog input/output.

This method is characterized by moderate price, high test efficiency, guaranteed test quality and less human intervention. However, this method lacks versatility is generally only applicable to machines equipped with fixtures.

3.PCBA Universal Automated Test System

PCBA universal automated test system designed for most manual testing and design. Because the test system is powerful, you can test a variety of PCBA and become a universal test system.

Humanized test principle: By sampling the model parameters, setting the error range, and comparing with the test board to determine whether it is qualified or not.

Simplicity test: Press the needle bar manually and the system automatically handles it. Product quality can be judged by the system, excluding the influence of human judgment factors. Moreover, its speed is incomparable to manual testing.

The system consists of acquisition, control board and test software. It is connected to a programmable AC/DC power supply and DC load. High sample rate products can be equipped with an external oscilloscope.

The system can test PCBA synchronization signals, user interfaces, modular programming environment models and conversions.

This method is costly, but testing is fast and requires no human intervention. It is versatile in its application and provides more comprehensive testing.

PCBA function test content

PCBA function test content voltage, current, power, power factor, frequency, duty cycle, position determination and other functional parameters of the measurement.PCBA function test contains content: general part:

1: The power supply part of the test–whether the power supply is working properly, test the voltage of each point–use a comparator or other.

2: Port (interface) test, whether there is Short & Open, resulting in abnormalities.

3: Integrated circuit module IC I/O read/write function test – Flash & EEPROM & CPU & SDRAM & logic IC etc.

4: Special function tests (different board requirements are inconsistent) – such as infrared, the need for external receivers.

Conclusion

At LSTPCB, we provide customers with complete PCB testing solutions and test all products. We have experience testing a wide range of PCBA products and can quickly provide test solutions to our customers to help them find the best test methods to improve performance, quality, manufacturability, reliability and reduce costs.

Difficulties and Challenges in PCB Design for Electric Vehicles

09/06/2023 在： /通过：

With the increasing awareness of environmental protection and the impact of fluctuating oil prices, more and more consumers are considering purchasing new energy vehicles as a means of transportation. In addition, the brand image and service quality of new energy vehicles are also improving, attracting more consumers. The market share of electric vehicles continues to grow, and more and more automakers are launching electric vehicles. Meanwhile, with the further development of battery technology and the improvement of infrastructure, the future development of electric vehicles is promising.

Electric vehicles have a very wide market, but the design requirements are getting higher and higher, which includes the difficulties of PCB design for electric vehicles. This article will give you a detailed introduction to the difficulties and challenges of PCB design for electric vehicles.

Difficulties in electric vehicle PCB design mainly include the following aspects:

1. High reliability PCBs and components installed on the board must meet high reliability standards, because it is related to the safety of operation and life. When the car works in a harsh environment, it will encounter vibration, shock and other problems, so the circuit must have a certain corrosion resistance and resistance to harsh environments.

2. High security requirements. The car must ensure the safety of the entire vehicle system, or even zero defects. In electric vehicles, the importance of information security is becoming more and more prominent, so security measures such as data encryption are required.

3.The PCB needs of electric vehicles mainly come from powertrain-related equipment, on-board equipment, battery management system (BMS), voltage conversion systems (DC-DC, inverters, etc.), and other high-voltage and low-voltage equipment, which require highly durable, reliable and rugged PCB applications.

4.PCB design needs to adapt to the evolving new energy drive system, so innovative PCB applications are needed to meet these needs.

PCB Design Challenges for EVs

PCBs play a vital role in managing complex EV electronic systems. Designing PCBs for electric vehicles comes with unique challenges that engineers and designers must overcome to ensure optimal performance, safety, and reliability.

Size and Space Constraints
To maximize limited space, PCB designers must optimize components and routing paths. The challenge intensifies as the demand for additional functionalities, such as advanced driver assistance systems, increases. Maintaining structural integrity while accommodating sensors, communication modules, and safety features is challenging.

Thermal Management
In electric vehicles, thermal management is crucial for reliable and safe operation. Designers must carefully plan and implement cooling mechanisms to prevent overheating and ensure long-term reliability. A combination of high-power components and limited space necessitates using advanced thermal management techniques like heat sinks, heat pipes, and thermal vias to dissipate heat efficiently.

Vibration and Mechanical Stress
Due to uneven surfaces and vehicle acceleration, electric vehicles are subject to various mechanical stresses and vibrations. PCB designers must ensure that their boards are durable and reliable in these conditions. These challenges can be mitigated by strengthening the PCBs, selecting suitable materials, and using techniques like shock and vibration damping.

Electromagnetic Interference
Due to high-power components and sensitive electronic systems operating close together, electromagnetic interference (EMI) is a big concern in electric vehicle PCB design. To minimize EMI and maintain signal integrity, designers must use shielding techniques, ground plane separation, and filtering. Compliance with electromagnetic compatibility standards and regulations is crucial to prevent interference with other vehicle systems and external devices.

Safety and Reliability
Electric vehicles have to be safe and reliable. PCB designers need to follow strict safety standards. It’s important to ensure the appropriate isolation of high-voltage circuits, implement redundant systems for critical functions, and validate PCB designs for reliability and fault tolerance.

Electronic systems for electric vehicles pose a lot of challenges for PCB designers. Managing power electronics, optimizing space, and addressing thermal management and EMI issues are all part of the design process. PCB designers can help make electric vehicles safer, more reliable, and more efficient by addressing these challenges head-on and leveraging innovative design techniques.

PCB designers working on EV projects can use Cadence tools to help with challenges for electric vehicle design. Cadence tools include PCB Design and Analysis Software and OrCAD PCB Designer.