Hello, where can we find an application note concerning ABLIC S-8252 protection circuits to correctly size the MOS and current protection.
Thanks for your help
Hello, where can we find an application note concerning ABLIC S-8252 protection circuits to correctly size the MOS and current protection.
Thanks for your help
Hello STM,
I do not see an application note available on the supplier’s website for S-8252. I will send a request to the product specialist to request it from the supplier if it is available. I will get back to you when I have more information.
The datasheet for the part is some 37 pages long in large part because it contains the requested application information. It just happens to be presented as a statement of the part’s various functions.
The remarks on table 11 offer important guidance, specifically that one should select FETs with a threshold lower than the over-discharge detect voltage, and a VGS(max) in excess of the charger voltage.
Understanding that the part compares the voltage between the VM and VSS pins to determine over-current states in either direction, and that this voltage is developed by the battery current acting across the combined RDS(on) of the two FETs is the next basic consideration.
Stated differently, one should choose FETs and a part variant in relation to each other so that the RDS(on) values together with VDIOV and VCIOV values of the selected part variant (see table 2) end up producing the desired current limits in either direction.
Finally (and these are out of scope for the ABLIC datasheet, so not spoken of much) one should:
A) do a thermal analysis to ensure that the FETs stay within permitted limits under all conditions permitted by the application, and
B) do a transient analysis to ensure that the safe operating area (SOA) of the FETs is not violated under any potential fault condition. The output impedance of the pins driving the FETs can be quite high, which is a risk factor for SOA violation/device failure in applications of this sort.