LTC4015 not charging the 3 cells Li-ion battery

Hello everyone,

I got a problem for designing the LTC4015 for charging 3 or 4 cells Li-ion battery. I designed follow the provided schematic from the Datasheet, but I change MOSFET models, shunt resistors.

When I was able to power up the board and read the registers via I2C. But when I connected the battery, the current draw from power supply stayed the same (14V and 0.021A). From I2C, I read the input voltage and battery voltage which are all correctly. Only the current is stayed around 10mA. It seems like the board is not trying to charge the battery at all.

For schematic as shown below, I change the model of MOSFETs and Shunt Resistors value to follow my requirement. And I didn't use the NTC with battery, so I use 10k ohm resistor instead as datasheet stated.

I really appreciate if anyone can help solve this problem. I really don't know where to debug this anymore.

Thanks in advance!


Some Updated: I read the register via I2C, from what I understand the register, I think there is no fault detected and the system is ready to charge. I powered up the board and plug the battery in, but there is no charging to the battery. When I measure between the BG pin and GND, the oscilloscope shows 0V straight. However, when I removed the Bootstrap capacitor Cb1, and I measure again, there is a small pulse (Shape like an AC signal not PWM). Could it cause because of the Bootstrap circuit here? 

/cfs-file/__key/communityserver-discussions-components-files/936/7774.schematic.pdf

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