direct current in contrast the other driver and overshoot circuits within the h bridge 300 may be used in writing a digital one by creating an effective current i eff that travels in the direction b consequently the reduced power driver 100 makes also is effective in synchronizing the overshoot current with the direct current which means that data may be effectively written either one or both of the drivers 310 320 may be a reduced power driver rpd 100 in one implementation these drivers may be a reduced power class ab driver that can either sink current or source current for this implementation the rpd in a preamplifier writer the class ab driver is the bottleneck for achieving fast rise fall times tr tf the class ab driver is slow because of the huge resistor capacitor rc parasitics placed at its input and internal biasing nodes to speed up the tr tf one possible way is to increase the bias currents through the input stages of the class ab however power consumption increases significantly alternatively either the driver 310 or the driver 320 may be drivers include current drivers that either sink or source current fig4 a is a block diagram illustrating a driver 400 that may be either one of the drivers 310 320 that is the reduced power driver 100 the driver 400 includes an input current driver 410 a current driver 422 current driver 424 dynamic booster 430 and an output switch 440 as indicated by the arrows current may flow from the input current driver 410 through the current drivers 412 414 to a control 443 for the output switch 440 in this implementation the output switch is a bipolar transistor so that the control.