LM5122: Current Sense position

Hi Baudouin,

Thanks for reaching out. Based on the principle of coupled inductors with a turns ratio of 1, the current between L3 and ground should be equal to the current flowing into L2.
As for the current between the low-side MOSFET and ground, I'm not sure if it's possible.

I'd like to look into this, could you please add the link to the old post you're referring to in this thread?

Thank you and best regards,
Bryan

Hi Brian,

Thanks for your answer, so nothing should cause problem in sensing current in L3 ? (for some reason we would prefer to have the current sense in this branch)
Because it isn't mentioned in the datasheet, I prefer to ask the question ! With such a configuration, there would be a slight negative voltage on the CSP Pin when the current becomes negative in the inductance at low load and forced PWM mode, would that cause any problem ?

The old post is : https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1038380/lm5122-current-detection-position

Hi Baudouin,

Thanks for the feedback. The same principles hold as in the old post.
The best option is to use the 'normal' solution which is described in the datasheet, if you wish to use a different implementation in your application, you would have to do some testing, to verify if your assumptions are correct.

Thank you and best regards,
Bryan

Hello Brian,

thank you for your answer but don't you have any precise recommendation about the current sense amplifier integrated in the IC ? Voltage ranges / values that should be verified before any testing ? (testing on a prototype does not guarantee that we use the component correctly.)

I can't find on the LM5122 datasheet if a blanking time is implemented on the current sense, is there one ?

Thank you and have a nice day,

Baudouin

Hi Baudouin,

I'll get back to you with some feedback today.

Thank you and best regards,
Bryan