Tajikistan Five solutions to high-voltage input module power supply(1)



There are many levels of conditions that can cause  high-voltage input module  Marine boost/buck voltage power supply failure:


1. The output working voltage of the  high-voltage input module  Marine boost/buck voltage power supply is reduced in the whole application process;

2. The DC DC power module stops working;



3. The output voltage of  high-voltage input module  Marine boost/buck voltage power supply is too high;


4. The input of  high-voltage input module  Marine boost/buck voltage power supply is short circuited;


Diode loss
Diode rectification is used in traditional rectification, and Schottky diode rectification is generally used under low voltage output conditions. Compared with other rectifier diodes, Schottky diodes have the advantages of faster switching speed and lower forward voltage, but Schottky diodes The forward voltage drop of the diode is related to the size of the rectified output current. The larger the rectified output current is, the greater the forward voltage drop, which may be as high as 0.5~0.6V or more, and the reverse leakage current of the Schottky diode is larger. .

module power supply

Temperature / humidity demand
The external ambient temperature of the rolling stock is - 40 ℃ ~ 50 ℃, and the internal air temperature near the electronic equipment may be - 40 ℃
~The temperature of the air near the printed PCB board varies between 70 ° C and 70 ° C. due to the influence of device heating, it is necessary to consider the over temperature of the starting process
The temperature range of printed PCB can reach - 40 ℃ ~ 85 ℃.
DC / DC power supply shall meet the strict requirements of temperature class TX, and shall not cause power supply when the ambient temperature is 85 ℃
Thermal protection and abnormal performance of on-board electronic equipment.

5. The output current of  high-voltage input module  Marine boost/buck voltage power supply is too large.


Next, let's analyze the above problems that will cause  high-voltage input module  Marine boost/buck voltage power supply failure one by one:


(1) In the first two kinds of  high-voltage input module  Marine boost/buck voltage power supply failures, it is usually not easy to generate a large risk, which can be checked and alarmed by the fault detection  Marine boost/buck voltage power supply circuit;

(2) The third failure method is more dangerous because it can damage the operating  Marine boost/buck voltage power supply circuit. Usually, the overvoltage protection can be built according to the overvoltage protection  Marine boost/buck voltage power supply circuit. The other form can be realized by adding a zener diode at the output end. The preventive measure we can take is to effectively select the parameters of the diode in the design scheme to avoid the change of the zener point due to different temperatures. However, some modules have built-in overvoltage protection. Generally speaking, modules below 25W have no overvoltage protection function, and only modules above 25W are designed with overvoltage protection circuit. The overvoltage protection point of the power module in the design will generally be designed as 135% - 145% of the rated voltage. Perhaps it is necessary to determine whether the module has this function already and can prevent repeated design schemes during the detailed design;