I need to design a power supply powered by a 9V cell battery to provide a dual polarity (one positive output and one negative with same magnitude of the positive's) power supply (say +/- 5V) with max. load curent of about 1A each rail.
even 0.5 amp. with a portable battery is a big requirement, either way is to reduce the load, but thats a poor solution.
Can't you remove the restriction of portable battery, then you can use a step down transformer and design the power supply fro any current specification.
i use this supply for microcontroller and an audio IC, all together about 300mA, i think. so cell batterys are light-weighted and convenient if it's capable to do the job.....
You can also use two groups of six AA cells and linear regulators for both + and -. NiCad cells can source large currents. Your battery life at 300 mA would be about 5 hours.