VOLTAGE DROP

[madivak]

Hi i recently updated an evaluation board for AW2042 (http://wiki.iteadstudio.com/Core_AW204x), that i  added more functionalities i.e wifi + Bluuettoth and Ethernet. But i have ran into some major Voltage drop issues. Every time i connect a 5V to the system, i instantly record around 4.5V at 5V test points which immediately starts to drop and finally hits 2.8V within 6 seconds or so. Now i need to start isolating the parts to identify where the problem lies. So to start with, has anyone ever had such issues and what are the obvious culprits here. Correct me if am wrong but i think that 6 seconds it takes for the voltage to drop means a component in the system is somehow charging up and causes the voltage to start dropping. Can someone please give me some advice on this?   

[danadak]

Sure sounds like the regulator supplying the 5V is going into thermal shutdown.

Add up all the current drains from the motherboard and all the ancillary
boards and see if your 5V supply has the specs to handle it.


Regards, Dana.

[madivak]

Thanks Dana, Let me check on that.

[madivak]

Found that the problem was the boost circuit i had connected to the 5V rail.
I removed it and the voltage drop issues were gone. Now i have a problem. What solution do i employ to ensure voltage drop is not an issue when i connect either buck, boost regulators?
For example i have an AMS1117 3V3 that takes in 5V and a 8V5 boost circuit that also takes in 5V. What design methods should i employ in terms of VIN on both of these 2 circuits to ensure they dont interfere with other peripherals that require the 5V?

[Fungus]

Every time i connect a 5V to the system, i instantly record around 4.5V at 5V test points

You are drawing too many amps.

[R005T3r]

Transport a higher voltage near to them and then conver it to 5V locally via an active regulator...

[madivak]

i just learnt a thing or 2 from Dev's video. I think current was was not enough.