PSU - Chinese current sensing modules

Projects / Smart Bench Supply

I guess I forgot to look at those popular Hall Effect current sensors from China using ACS712.

The parameters Noise and Total Output Error are the ones of interest.  The total output error isn't too bad and in some cases can be calibrated out.

There is a tradeoff between the amount of noise vs bandwidth.

Resolution: 21[mV] / 185 [mV/A] = 0.114A (typ) for a 47nF cap. This is the part that fails this application.

I guess that's why those Chinese ACS712 modules are cheap.  The ACS723 based modules are available elsewhere, but not yet from China until the existing cheaper stocks of ACS712 runs out.

The new replacement part seems to be improvement on the noise, but worse on the accuracy.

The other popular modules are MAX471 (pdf)  which is also designated ''Not for New Design''.

Here are the gotchas: minimum input voltage and large error at current below 0.1A.