Misterbenn
Active Member
Hi guys i'm having some problems with a battery charger circuit, using the max 1647.
I've had it responding to its address and was working on setting voltage and current limits when the problem occured.
The first indication was the SDA line was being pulled down from a 'high' 5V to about 2.4V. Its like the chip is trying to take control of the SDA line but cant quite manage it. And this is on start up - when it really shouldnt be taking control as its only a slave.
Also the VL pin is low - but the REF pin is at a valid 3.9V. Anyone that looks up the datasheet will notice this is a bit odd as REF depends on VL. for this all i can think is that the VL pin is broken but not the internal circuitry. - however a low VL may explain SDA being pulled down....
clearly i've checked my circuit - it seems fine to me!
I've had it responding to its address and was working on setting voltage and current limits when the problem occured.
The first indication was the SDA line was being pulled down from a 'high' 5V to about 2.4V. Its like the chip is trying to take control of the SDA line but cant quite manage it. And this is on start up - when it really shouldnt be taking control as its only a slave.
Also the VL pin is low - but the REF pin is at a valid 3.9V. Anyone that looks up the datasheet will notice this is a bit odd as REF depends on VL. for this all i can think is that the VL pin is broken but not the internal circuitry. - however a low VL may explain SDA being pulled down....
clearly i've checked my circuit - it seems fine to me!