Multiple voltage output issues

lym1210

Multiple voltage output issues [Copy link]

Hello, seniors. I use a 20v DC power supply as input and want to generate 8 5V voltage outputs using a voltage regulator chip. I would like to ask the seniors, is it better to use a voltage regulator chip to generate 5V and then connect it to the 8 ports of the connector for output, or to use 8 voltage regulator chips, each of which generates 5V and then connects to the 8 ports of the connector for output?

maychang

Both methods are OK, depending on your needs. Each channel has an independent voltage regulator chip, and the outputs of each channel have little impact on each other. A voltage regulator chip generates a 5V output voltage and then connects to 8 ports, and the outputs of each channel have a large impact on each other. If you can accept the impact between the channels, then using a voltage regulator chip solution is less costly.

lym1210

maychang posted on 2018-9-19 15:18 Both methods are OK, depending on your needs. Each channel has an independent voltage regulator chip, and the outputs of each channel have little impact on each other. A voltage regulator chip generates 5V output...

If one is used, do you have any suggestions for the wiring on the PCB board? Is the wire that generates 5V from the voltage regulator chip very thick?

bqgup

It is best to use multiple 7805 voltage regulator chips, because there are more load interfaces, and the 7805 voltage regulator chip has a big problem, that is, it will get hot when working, very hot. The heat generated by using one 7805 for 8 ports and 8 7805 for 8 ports is imaginable.

maychang

lym1210 posted on 2018-9-19 15:39 If one is used, do you have any suggestions for wiring on the PCB board? Is the line that the voltage regulator chip generates 5V very thick?

"Is the line that the voltage regulator chip generates 5V very thick?" It depends on how much current each of the 8 ports needs to output. Of course, the wider the line is, the better.

懒猫爱飞

1) See how big the power is. 2) See what it is powered by. If the power is small, the impact is not big, and you can use one. 3) If the current is large, or the interference is large, it is recommended to use multiple DCDCs directly. If you use LDO to directly reduce 20V to 5V, if the current is large, the heat generated will definitely be large. 4) Regarding the line width, the wider the better. You can check the relationship between current and line width on the Internet and set a suitable value.

chunyang

The load must be analyzed, including the size of the load, the requirements for power supply ripple, whether different loads will affect each other if they share a power supply, etc. Without a good load analysis, general discussions on which solution is better are meaningless and are no different from blind guessing.