I am currently using a board with an LTC1760 to charge smart batteries. I'm having a problem with the buck fonctionnality. The schematic of my board is exactly the same as the schematic given on the datasheet (typycal application) :
Communication with smart batteries works. By visualizing the registers I see that by inserting a battery the system is ready to charge. The LTC1760 starts Buck operation but something goes wrong. If I visualize the voltage at the output of Rsens that's what I have :
Vin = 19V
It looks like the LTC1760 try every 250ms to restart buck. It force the QTG to stay open.....
If I look on the Vset pin the voltage is on the limit of the 0,8V reference voltage:
Any Idea ? thank you in advance
Can you show plots of buck operation on the TGATE, BGATE, and SW nodes? Also, what is the part number for the switching FETs and what is your battery model?
The switching fet are FDS8949. I can't give the model of the battery but is a Lithium ion smart battery. The battery is ok (volatge, current, cells ...) . The battery also respond to the Current() Voltage() ChargingCurrent() ChargingVoltage() function send by the LTC1760.
Here is the TGATE plot :
BGATE plot :
Can you tell me the requested ChargingVoltage() and ChargingCurrent() of your battery at the moment?
Can you also send me your layout? If you would like to do that privately, my email is [removed].
The cause was found to be a layout issue and has been resolved offline.