L6480 Mosfet driver

rengholm · ‎2013-03-18

Posted on March 18, 2013 at 23:51

What is the smallest RDS on value that will work with the L6480? How do I set the

phase current to 2.3 amps?

Enrico Poli · ‎2013-03-19

Posted on March 19, 2013 at 14:21

Hello,

In theory there is no limit to the RdsON value of the external MOSFETs. Lowering the on resistance has the following drawbacks:

- the commutation speed is lower because MOSFETs with a lower RdsON usually has an higher total gate charge (the total gate charge of your target MOSFET should be lower than the IGATE x TCC product)

- The overcurrent protection triggers at higher values. The overcurrent protection of the L6480 monitors the voltage drop on the RdsON: the lower the resistance, the higher the current threshold.

The device is based on the voltage mode algorithm, so you need to calculates which is the proper voltage vs speed curve which allows you to obtain the target current.

You can use the BEMF compensation tool integrated in the

http://www.st.com/web/en/catalog/tools/PF258265

in order to evaluate the proper configuration parameters.

Regards

Enrico