Ask, I use the recommended 5V conversion circuit in the LM2576S-5 power chip manual to power one of my development boards, which require a lot of power (the official adapter is the maximum 5V, 2A). When I was not connected to the load, the power supply circuit stably output 5V, but when I switched on the development board, the voltage instantly dropped to 4.4V, and then returned to 4.5V, the development board could not start normally, so I used two of these circuits, And connect them in parallel, the voltage is adjusted from 5V to 4.4v, and then back to 4.6V, but the development board can be turned on normally, what I want to know is, can't the maximum current stated on the chip reach 3A? Why is there so much pressure drop? It shouldn't be because of insufficient power.
Malik Posted on August 4, 2020
First of all, you have to determine whether the power of the front-end circuit is sufficient, that is, the voltage and current at the input of the LM2576. Secondly, check the back-end circuit to see if it is overloaded or short-circuited. Generally, if there is no problem with the front and rear stages, adjust the capacitance and inductance in the middle.
Ellis Posted on August 4, 2020
Two power supplies together means that your development version is okay. Check if your power supply is not enough?
Hanna Posted on August 4, 2020
See if the input power is small, and try increasing C25
Phoenix Posted on August 4, 2020
It is possible that the power of VBAT is not enough, and the feedback line of pin 4 is far away from the inductor.
