rather than the battery alone the circuit 220 communicates to the power module 230 that the system is operating in a high intensity state the power module 230 then generates an ac signal to drive the ccfl 240 based upon a high intensity load otherwise if the circuit 220 determines that the system is running in a medium intensity state the power module 230 generates an ac signal to drive the ccfl 240 based upon a medium intensity load power module 230 may comprise an inverter to generate the ac signal one embodiment of power module 230 will be further described below in fig5 for another embodiment of the invention the circuit 220 for determining the required ccfl 240 load is performed through system software instead of hardware computer systems often have a range of brightness settings that may be controlled using an operating system os sensor control for example the os sensor control may be used to interpret the brightness setting made through a potentiometer a keyboard entry or an analog brightness adjustor the system software then determines the range of brightness settings to transmit to the power module 230 the power module 230 takes the brightness setting and generates an ac signal to.