Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1231
| Posted: 10:39pm 29 Oct 2020 |
The whole purpose of presenting a schematic is to enhance the understanding of the circuit for others to follow or reproduce. The OCP circuit relies on either the pin 5 terminal going positive WRT pin6, or the pin 6 terminal going negative WRT pin 5.
If it is relying on a voltage drop formed on a PCB track then that can be considered as a resistor or shunt and should be drawn as such. As it is currently drawn it is wrong as it is drawn as equipotential points and cant work. So I stand by my original point that there is an error as presented !
Had someone decided to lay out their own circuit without the special knowledge you enhanced on in your second attempt it would not work unless by accident.
Pin4 of the buck converter (on/off/shutdown) pin should be tied to ground if unused.
Does the output resistor/shunt exist as a part or is it a PCB trace also ?
Its a shame that their cheap? brilliant? implementation oscillates and carries on and needs extra work to function properly (assuming the mods do actually fix it 100% for all units). I would not do it their way.