AP1084 Problem

[cosciss]

I purchased 2 AP1084 voltage regulators (5v 5a) from madvapes.I built a box mod with 2 14500's in series using the AP1084 and 2 10v 10microfarad caps (with a homemade heatsink for the regulator). The heatsink will get warm but it only puts out a little over 2v.

I bulit another circuit, same as the first without the caps, with the same result.

I must be missing somethig, I just dont know what it is. Any help would be apreciated.

Thanks

PS: I chose a 5a regulator because i like 1.6 ohm dual coil carto's.

 

[CapeCAD]

You did not add any additional components besides the caps?

 

[cosciss]

No, I didnt add any other componets besides the caps. Is that the problem?

 

[CapeCAD]

No, I didnt add any other componets besides the caps. Is that the problem?

No, this fixed output device should output 5V with nothng but capacitors. The things to check are that your input voltage is high enough (Over 6.4V for full load), that your solder joints are good. that it is wire correctly. and that you capacitors are installed correctly.

 

[cosciss]

I double checked everything. I dont understand. I dont think I'm an idiot (but would I really know?). Any other Ideas?

 

[TomCatt]

cos
with the second circuit, was this using the same regulator as the first, or did you use your second regulator? In other words, are both regulators giving you 2V out, or only the one regulator?

Here's a link to an AP1084 datasheet - http://www.diodes.com/datasheets/AP1084.pdf. I notice this regulator comes in a number of voltages, including 1.8V and 2.5V. Is there any identifying writing on the regulator(s) that indicate that it is, indeed, a 5V regulator?

I'm not even an electronics amateur , but those are a few things to look into.

Good Luck and let us know if you figure this out.


Oh...another suggestion....give MadVapes a call and see if they have any info on this happening to other customers (or post in the MadVapes forum).

 

[cosciss]

I used the second regulator. I purchased it from Madvapes, so I assume its a 5v5a regulator.

 

[jrm850]

My first guess would be that you have the polarity reversed on one of your caps. Also check the ESR on the output cap. Diodes Inc usually has pretty specific esr requirements for output stability.

 

[jhonutz]

hy
so you must use two battery connected in series, voltage in must be 8.4 at full charged. And in datasheet prezent a resistiv divizor with two resistor at page 6 from @tomcatt link. If you put instead of R1 or R2 an semireglabil you have made a VV with voltage range 0- 8.4V at fully charged.

Anyway, it`s much better to use an stepdown switching regulator from TI or Muratta

Good luck

 

[WillyB]

For trouble shooting pull the caps, it should work fine without them. Pull the heat sink also. The tab on these is odd as it's actually a Vout (pos). Basically strip it down to the bare essentials.

The suggestion to check the numbers on the chip and compare them to the datasheet (there is a chart) is also sound. When you say you are getting ~2V that almost sounds like the reference voltage a naked adjustable reg would put out.