  Resistive switching devices, important for emerging memory and neuromorphic
applications, face significant challenges related to control of delicate
filamentary states in the oxide material. As a device switches, its rapid
conductivity change is involved in a positive feedback process that would lead
to runaway destruction of the cell without current, voltage, or energy
limitation. Typically, cells are directly patterned on MOS transistors to limit
the current, but this approach is very restrictive as the necessary integration
limits the materials available as well as the fabrication cycle time. In this
article we propose an external circuit to cycle resistive memory cells,
capturing the full transfer curves while driving the cells in such a way to
suppress runaway transitions. Using this circuit, we demonstrate the
acquisition of $10^5$ I-V loops per second without the use of on-wafer current
limiting transistors. This setup brings voltage sweeping measurements to a
relevant timescale for applications, and enables many new experimental
possibilities for device evaluation in a statistical context.
