Concerning CLR Discovery

[jay mitchell]

I see.

This got me curious so I looked at the documentation here: UcD250LP_OEM/UcD180LP_OEM which mentions an internal regulator for VDR in the absence of an optional external VDR - For the UcD250LP, seems to be a 15V VDR and for the UcD180LP a 12V VDR.

Hypex chose this route because the output devices are in a "totem pole" arrangement, so the negative MOSFET's gate voltage must be referenced to the negative supply rail rather than to circuit common. Rather than use a relatively inefficient linear regulator for the purpose, they could have either put a DC-DC converter in the amp module or provided the required voltage in the power supply.