I'm pretty sure HTC's engineers know how to design a charging circuit for the battery in their phones (more than anyone here most likely
). Lithium ion batteries do not need to be trickle charged and chargers do not trickle charge them (which actually means charging at a batteries self-discharge rate). Trickle charging only applies to ni-cad and nimh batteris. If you feel charging slower is better for you, you either need to only charge from a usb port with normal battery driver or re-write the battery driver for your diamond to charge slower from the wall socket. It slows down when it nears full charge, which is important to maintaining li-ion battery life from what little I've read.