I am currently doing a project on mobile chargers. I have actually done this circuit based on the circuit of a chinese product available in the market. As a result, i was not able to get the design or working from anywhere. Please do help me bcos my exams are tomorrow. I specially need help about the IC BBv7B. I think it is a step up IC. Do help me. If possible, help me with some datasheets also. I have provided the circuit as a attachment