Automatic 2S Li-ion Charger Control

I’m building a small home-electronics product that runs from a 2-cell Li-ion pack (8.4 V when full). I need a proven control circuit that automatically disconnects a 9 V wall adapter – routed through a... (Budget: ₹1500 - ₹3000 INR, Jobs: Analog Electronics, Electrical Engineering, Electronics, Embedded Systems, Microcontroller, PCB Layout, Prototyping, Simulation)