Before the veterinary B-ultrasound system powers on the circuit board, first of all, you should pay attention to eliminating the process errors such as wrong wiring, open circuit and short circuit caused by the processing of the veterinary B-ultrasound machine printed circuit board, and also pay attention to checking whether the schematic diagram of the veterinary B-ultrasound machine designed by you and the printed circuit board are consistent in the connection. After the power conversion chip is soldered, each pin is carefully checked to eliminate the influence of cold soldering and leaking soldering. After doing the above work, the power-on test can be carried out.

Since high voltage and low voltage coexist on the board in the veterinary B-ultrasound system, and there are many types of power supplies, the power supply has particularly stringent requirements, so whether the power module works normally is directly related to whether the circuit board can work normally.

For the 1.2V voltage that the veterinary B-ultrasound system uses to power the FPGA, a big problem was encountered during the debugging process. After the FPGA chip, power conversion chip and filter capacitor in the veterinary B-ultrasound system were all soldered, the 1.2V power supply network and ground network were short-circuited by measuring with a multimeter, and the cause of the short circuit was immediately found. It was suspected that there was a problem with the filter capacitor or that the zero resistor was welded to the position of the filter capacitor. However, after careful search and comparison, it was found that there was no problem with the capacitor. The multimeter was used to measure the short circuit between 1.2V and the ground. There was no choice but to remove all the filter capacitors related to the 1.2V power supply. The result was still no change and it was still short-circuited. Finally, there was really no choice but to remove the power conversion chip, but after measuring with a multimeter, it was found that it was still short-circuited. At this time, by looking up relevant information, I gradually realized that the 1.2V network may have a relatively small resistance to ground. As a result, it was found that its resistance to ground was only about 40ohm. Therefore, it is normal to have a sound when measuring the short circuit with a multimeter. After re-soldering the power conversion chip and filter capacitor, the power-on test found that the voltage value of the network was 1.194V, which met the requirements for powering the FPGA, and the 1.2V power supply voltage problem was solved.