How to solve the power failure of the DC-DC module and the classification of danger levels

Because the modular power supply is easy to install and its structure has many advantages, so in the fields of mobile communication and switching equipment, we can often see the design related to the modular power supply, which shows that the application of the modular power supply is very extensive. Although the DCDC power module has high reliability, it is not without damage. From the level of DC-DC module power supply design, the editor will tell you how to solve the DCDC power supply module failure and what kinds of danger levels are divided into!

Several common faults of DCDC power modules are manifested: the output voltage of the module drops during use, the module stops working, the output voltage of the module is too high, the input of the module is short-circuited, and the output current of the module is too large.

To distinguish from the degree of risk, the risk of output voltage drop and module shutdown is relatively low, which can facilitate circuit diagnosis. The following three problems are more risky.

When the input of the module is short-circuited, it will cause the printing plate to be burned. This serious problem can be prevented by placing a fuse on the input end. The fuse should generally be placed close to the input end of the power module when wiring. The intention of this plan is to reduce the bow|line inductance of the input line to avoid the lead inductance bowing|overvoltage on the input end when the fuse is blown. When the output voltage of the module is too high, it may cause the DCDC power module to burn the circuit, which is a relatively risky problem. Generally, maintenance is achieved through an overvoltage maintenance circuit, and others can also be achieved by adding a Zener diode at the output. When planning, the parameters of the diode should be selected reasonably to prevent the change of the voltage regulation point due to the different temperature i. Some modules have their own overvoltage maintenance. Generally speaking, modules below 25W have no overvoltage maintenance function, and modules above 25W have internal overvoltage maintenance circuits. The overvoltage maintenance point is generally planned to be 135%-145% extra voltage. In the specific planning, it is necessary to find out whether the module has these functions, so as to avoid duplication of planning.

If the output current of the DCDC power module is too large, then you need to select a power module with over-current maintenance function for planning. -The general power module has the function of over-current maintenance. This kind of module can be realized by detecting the current of the primary side or the secondary side of the changer, but it will lose a certain amount of power. When selecting voltage modules, it is not that the larger the extra power, the better. If the derating is too large, when the user board is short-circuited, because of the transmission voltage drop, the output current is not enough to realize the module overcurrent, which may cause the chip to overheat or even be damaged.

Dcdc power modules are widely used in communication, network, industrial control, railway, military and other fields due to their small size, outstanding performance, and convenient use.