Now referring to FIG. 4, a voltage difference amplifier and comparator arrangement is provided. As shown, voltage difference amplifiers A5, A6, A8, A9 are positioned across the respective capacitors C1, C2, C3, Cn. The output of the voltage difference amplifier is provided to the respective comparators A1, A2, A3, A4 which compare the output with the reference voltage Vref. The output of the comparator is provided to the controller to determine the switching of the switches to achieve the desired output of the system.

Now referring to FIG. 5, a flowchart of a method 500 for operating a DC-DC converter for current controlled solenoid drive is provided. The method 500 begins at block 502 and continues to block 504 which provides for providing a charge pump circuit having a plurality of stages, wherein each stage includes a constant current source, a switch, and a capacitor. Block 506 provides for charging the capacitor of each of the plurality of stages. The capacitors of each stage are charged which receives current from the constant current source for each stage. The capacitors are charged to a predetermined voltage. The voltage of the capacitor is compared to a reference voltage to determine whether the capacitor should continue to be charged by the constant current source or charging should be discontinued.