6.3V @ 150mA

6.3V @ 250mA

2.5V @ 500mA

2V @ 60mA

I have to use at least one of each bulb, but I can use more than one, if I want to. The applied voltage is 9V. The hard part about making this circuit is that it has to be somewhat power efficient. The bulbs should use at least around 60+% of the circuit. the smallest resistor I can use is a 2.7 Ω. I have come up with some circuits that will work but they are not very power efficient. The highest power efficiency I can come up with is about 45%. Anyone's help on this will be greatly appreciated.