Voltage clamp circuit connection
-
Basicmicro Support
- Posts: 1594
- Joined: Thu Feb 26, 2015 9:45 pm
Re: Voltage clamp circuit connection
For MCP boards there are two options. Use a DOUT pin directly connected through a power resistor(2 to 10ohms 50watts or more) to B+. This will work for disipation upto 3.5 amps per DOUT pin.
Second option is using an external mosfet(like the one we recommend for Roboclaw voltage clamp circuits). There is a mistake in the diagram in the MCP user manual in regards to the pull-up/down resistor.
The wiring should be:
1. DOUT to mosfet Gate.
2. Pull-UP resistor(not pull-down) to 5v on the mosfet gate.
This is because the DOUT pins are open drain outputs only(eg they onlyy pull low so you need the pull-up to produce a high). The pullup resistor should be around 1k. The rest of the connection(drain and source pins on the mosfet) are shown correctly in the manual.
Second option is using an external mosfet(like the one we recommend for Roboclaw voltage clamp circuits). There is a mistake in the diagram in the MCP user manual in regards to the pull-up/down resistor.
The wiring should be:
1. DOUT to mosfet Gate.
2. Pull-UP resistor(not pull-down) to 5v on the mosfet gate.
This is because the DOUT pins are open drain outputs only(eg they onlyy pull low so you need the pull-up to produce a high). The pullup resistor should be around 1k. The rest of the connection(drain and source pins on the mosfet) are shown correctly in the manual.