Abstract: Systems and methods to charge a battery using a switch modulator and a shaping circuit comprising at least one switching element. The shaping circuit may be configured to receive an input charge supply from a power supply and the switch modulator may be operably coupled with the at least one switching element. Further, the switch modulator may actuate the at least one switching element at a selected duty cycle such that the shaping circuit produces a shaped charge signal, the selected duty cycle configured to vary within a switch modulator sample period.