1. An apparatus for driving light emitting diode (LED) elements comprising: an error amplifier; a pulse width modulation comparator electrically connected the output of said error amplifier; a DC-DC converter electrically connected to the output of said pulse width modulation comparator and an output pad; at least one light emitting diode (LED) electrically connected to the input of said error amplifier; and an exponential current digital-to-analog converter (IDAC) using least significant bit (LSB) and a binary weighted most significant bit (MSB) wherein said binary weighted most significant bit (MSB) is electrically connected to said cathode of said light emitting diode (LED) and input of said error amplifier wherein said binary weighted MSB is defined according to a specified relationship for IMSB providing an MSB code for the MSB network initiating the MSB switches.