Mr.HAN: HAN port duplicator

In Norway, all households are equipped with smart power meters locally known as AMS (avanserte måle- og styringssystemer; advanced measurement and control systems) meters. Those meters have a RJ-45 jack which gives access to the HAN port (home area network). The Norwegian Electrotechnical Committee has more infos.

Since I'm using an Easee Equalizer for capping my EV charger's maximum power draw depending on the household's current power consumption, the HAN port was occupied. Since the Equlizer already draws the maximum 700 mW the HAN port provides, a little bit of electronics were required. Enter, Mr.HAN:

Some notes on the design:

• The USB interface and therefore the computer is galvanically isolated from the HAN port.
• The input is as high impedance as possible in order to give the other HAN port as much of the available power as possible.
• The previous point required powering the opto-coupler from USB via an isolating DC/DC converter module.
• The comparator is selected to handle the rather high input voltage and tolerate the input voltage even it's not powered. In addition, it has quite a low input bias current.
• The DC/DC converter is regulated which simplifies the design a bit.
• The opto-coupler has a low forward current.

Of course, the name was inspired by Spaceball's similarly named machines.