A current monitoring circuit is disclosed. The current monitoring circuit includes a main transistor arrangement for connection in series with a load and a set of one or more measurement branches in parallel with the main transistor arrangement. Each measurement branch comprises a series resistor and switch for controlling the connection of the branch into circuit. A gate controller is provided for controlling the switching of the main transistor arrangement and branch switches and a sense amplifier is included for measuring a current through the load based on the current flowing through the main transistor arrangement or a branch.