I’m working on a project where I need to provide 5V DC output. I’m using the AMS1117-5 voltage regulator to step down 12V to 5V, and it works perfectly for that purpose.
However, sometimes the input voltage is already 5V instead of 12V. In this case, I’d like to bypass the AMS1117-5 and send the 5V input directly to the output, avoiding unnecessary regulation.
because i think ams1117-5 needs voltage at least 6.2v as input
Is there a way to implement this kind of switching mechanism, or a circuit design that can automatically detect the input voltage and route it accordingly?
@jim-p - I understood his project to have one single power source that would usually provide 12V, but could sometimes only provide 5V. In other words; he seems to have a power supply with varying voltage, where 5V is insufficient to be regulated to 5V through the ams1117-5.
device works with 5v. and sometimes someone can put 12v input. so if someone put 12v i want to send it via AMS1117-5 and if someone provide 5v input i want to power the board directly
What you could also do is use a different regulator with a much lower dropout voltage. For the AMS1117-5 the typical dropout voltage is 1.1V, so the minimum voltage difference is much higher than for instance for the HT7350 (dropout is 60mV).
Note: maximum input voltage for the HT7350 is 12V, for the AMS1117-5 it is 15V.
I try to use different socket types to minimize accidental supply of incorrect voltage.
So I give my 5V devices a USB input socket (mostly micro-usb). That kind of makes it easy not to accidentally provide other voltages and allows using a regular USB power supply or a powerbank.
For a device with varying input levels I used a 5.5x2.1 DC barrel jack connected to a mini360 buck converter to make the 5V for the MCU.
