I am designing a battery management system for lithium ion batteries. I am referring a schematic that is already available.
I do not understand the function of the two MOSFETs marked in the schematic.
Asked
Active
Viewed 460 times
1
-
1Have you looked at the datasheet of the chip that is driving those MOSFET gates? If so, was there commentary in the datasheet that you need help interpreting? – nanofarad Dec 17 '21 at 04:31
-
I can understand one is for charging and the other for discharging. How do they work here? – BlackHawk Dec 17 '21 at 04:40
-
They either conduct or they don't. You need two back-to-back because of the body diodes (on mobile so no time to write full answer) – nanofarad Dec 17 '21 at 04:57
-
1A BMS does not charge a battery. It is not a battery charger. As explained, the 2 Fets are here to disconnect the battery to protect it (under-discharge, over-charge, over-temperature, overcurrent etc). 2 Fets are needed because Mosfets have a parasitic body diode that will let the current flow from Source to Drain. A second Mosfet in the opposite direction is necessary to interrupt the current in both directions. – romain145 Dec 17 '21 at 10:11
-
The CFOUT and DFOUT pin descriptions in the datasheet should have all the info you need. – Dec 17 '21 at 14:56
-
What is the purpose of a MOSFET switch when the fuse has blown off? – BlackHawk Dec 21 '21 at 07:32
1 Answers
1
They together work as a bidirectional relay.
It's a well known circuit in literature.
The states of this solid state relay are: ON or OFF.
When the relay is in the ON state, current can flow in both the directions.
Enrico Migliore
- 4,679
- 1
- 9
- 12
-
-
I can't answer. I would have measured the output and input currents and would have turned off the MOSFET's under overcurrent conditions instead of using a slow fuse. – Enrico Migliore Dec 21 '21 at 16:04