Tool/software:
I have a design for BQ25170 that is almost identical to the application note for charging a single cell Li-po battery but when supplied with 5V for VIN the chip appears to turn on and off at a period of around 2 seconds. I have populated only the schematic seen below on a board and the problem still persists. The battery connected at VBAT is 1200mAh though I have also tried a 2200mAh one with the same results. Given enough time the battery will eventually charge up through the sequence of short pulses but it takes much longer than it should and the STAT pin turns on and off with the charger. When the battery voltage gets around 4V it does go into a continuous charge mode per the datasheet. What needs to be tweaked to get this to work without pulsing when the battery voltage is from 3.4 to 4 V?
Here is what it looks like with the oscilloscope measuring VBAT:
And here is the board layout: