A controller is disclosed for a voltage regulator module including a power unit and providing an output current, Iout, at an output voltage, Vout, from an input current/voltage and being configured for use in a multi-module voltage regulator having a neighbouring voltage regulator module having a respective output connected in parallel, the controller comprising: a reference voltage source for providing a reference voltage; a current balancing unit, configured to receive a respective output current from the or each neighbouring voltage regulator module and to determine an adjusted reference voltage, from the reference voltage and for balancing the output current with the at least one respective output current; and a control unit configured to use the adjusted reference voltage to control the voltage regulator module, to provide the output current at the output voltage from the input current at the input voltage, based on adaptive voltage positioning regulation.