Reverse CUrrent in sync buck charger system.

Status
Not open for further replies.
L

ljy4468

Full Member level 4
Joined
Jul 20, 2005
Messages
232
Helped
13
Reputation
26
Reaction score
1
Trophy points
1,298
Location
South Korea
Visit site
Activity points
3,023
Hi all I have a question about reverse current in sync buck charger.

Please refer to below articles and
https://www.ti.com/lit/ml/slyp089/slyp089.pdf

My question is in Fig. 22.

When a charger is started with battery connected, a huge negative current flows from the battery.
I don't understand how these huge current flows during startup,,,

Anyone can help me?
 

That current flows only if the buck converter is using a low-side FET as a synchronous rectifier to ground and not a diode. If the FET is on when the inductor current reverses direction then it will conduct large currents to ground from the battery. If a diode is used instead of a FET (at some loss in efficiency) then that path is blocked.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…