TPS65950 USB Power Back to back FET explanation

Guy Adams

Other Parts Discussed in Thread: TPS65950

Hi,

Is there an explanation for the back to back FET layout for the USB charging with the TPS65950 as it would be possible to to connect and modulate current with one FET? Is the reason for the second FET to provide a block to reverse current flow because of the body diode? Which FET is switched and which used for on/off?

Thanks

Guy

over 8 years ago

0 Kevin Selva Prasanna V over 8 years ago

TI__Intellectual 1295 points

Guy,

Hi there. I wanted to make you aware of another thread also related to USB charging using the TPS65950. Hopefully this helps.

e2e.ti.com/.../622194

0 Guy Adams over 8 years ago in reply to Kevin Selva Prasanna V

Prodigy 20 points

Hi Kevin,

Thanks - I was aware of this thread but was probing for a more detailed description of how the lower (on/off FET) actually works given that if the upper FET is 'regulating' (i.e. has a voltage higher than VBat) and one wants to switch off current to the battery using the lower FET then it appears that the body diode prevents the lower FET from disconnecting the charger......

Guy

Power management

Power management forum

TPS65950 USB Power Back to back FET explanation