Differential laser diode driver apparatus and systems

Apparatus and systems create differential drive signals suitable for HAMR data recording. A laser diode differential driver provides heating current pulses at a time Φ1. The pulses energize a laser diode to pre-heat the magnetic medium to be written. Some embodiments duplicate portions of the laser diode circuit architecture to create a magnetic write head differential driver. The write head driver provides write current pulses to a magnetic write head in one direction with θ1 timing and in the opposite direction with θ2 timing. Both drivers utilize sets of reference voltages capable of being switched to one terminal or the other of the element to be driven. In the laser diode case, the common mode is split between the anode and cathode sections of the driver. A feedback element is added between the cathode and anode sections to provide current accuracy independent of the electrical characteristics of the selected laser diode.