You have two main choices for DC step-down: Linear Regulator: Inexpensive. Throws away excess voltage as heat. DC to DC Converter: More expensive. More efficient.You didn't say what the input voltage is (your 5A supply). You didn't say what the power requirement on the three output lines (4.5V, 6V and 9V) are. You did say 1.6A but is that one EACH or all combined?
Do I need an extra heating tank for it? Or maybethere is no need for it if the current is less than 1A???
9V -> device /12V -> device \ 9V -> device \ 6V -> device \ 4.5V -> device