now ive been in a need to builed a portable 5vdc power source, so i decided to go with a 9v battry because its simple, and no need to MAKE MUCH ROOM FOR 4X1.5V BATTRIES(which ill also wont give the wanted result, theyl give me a 6v and i need exactly 5v), now the thing is im searching to builed a circut that will efficentlly lower the losses that for converting 5vdc to 9vdc, and NO I DONT WANT TO USE 7805 ITS NOT POWER EFFICENT and it dont work well when the voltage lowers under ~8vdc ...
so any information on the matter will be helpful