the output voltage waveform 510 inductor current waveform 520 and switch node waveform 530 the output voltage waveform 510 is shown to be holding at approximately 10 8 v the inductor current waveform 520 ripples at 1 8 v out fig5 is a plot of voltage waveforms from the circuit of fig3 with an average level of 6 v out the switch node waveform 530 shows that the duty cycle is about 83 3 thus the circuit 200 is a charge boost system that can increase a bus power voltage from a nominal 5 volts in the case of usb to a higher voltage with support for substantial current in cases where the power is supplied for the purpose of illumination this increase in voltage allows for more leds to be placed in series also called u201c strings u201d to better utilize the current for illumination because there is a higher potential on the string more leds can be placed allowing a given amount of charge to do more work and reducing losses caused by thermal dissipation in a preferred application a set of 24 leds is fired simultaneously the set of leds is arranged in one or more rings around the camera to illuminate a semiconductor wafer during the camera 39 s exposure time for machine.