An intermediate bus converter operable to generate an intermediate bus voltage (V IB) for use in an intermediate bus architecture power system having a plurality of point of load regulators (202, 203, 204), the intermediate bus converter comprising: a converting unit operable to receive an input voltage (V IN) and a control signal and operable to generate an intermediate bus voltage (V IB) based on the input voltage (V IN) and the control signal; and a table storage unit configured to store a table relating respective output power regions of the converting unit to respective intermediate bus voltages which reduce power loss; a measuring unit operable to measure the output current (I out) of the converting unit on the intermediate bus and to measure the output voltage (V out) of the converting unit on the intermediate bus; and a controlling unit operable to receive the measured output current and the measured output voltage, calculate an output power of the intermediate bus converter in dependence upon the measured output current and in dependence upon the measured output voltage, determine an intermediate bus voltage (V IB) to reduce power loss in dependence upon the calculated output power of the intermediate bus converter, and generate a control signal for controlling the converting unit to generate the determined intermediate bus voltage (V IB) so that the intermediate bus converter itself determines an intermediate bus voltage to reduce power loss and performs voltage control to achieve the determined intermediate bus voltage without receiving output current and output voltage measurements from the point of load regulators (202, 203, 204), wherein the controlling unit is operable to determine the intermediate bus voltage (V IB) to reduce power loss by reading an intermediate bus voltage (V IB) from the stored table in dependence upon the calculated output power. a converting unit operable to receive an input voltage (V IN) and a control signal and operable to generate an intermediate bus voltage (V IB) based on the input voltage (V IN) and the control signal; and a table storage unit configured to store a table relating respective output power regions of the converting unit to respective intermediate bus voltages which reduce power loss; a measuring unit operable to measure the output current (I out) of the converting unit on the intermediate bus and to measure the output voltage (V out) of the converting unit on the intermediate bus; and a controlling unit operable to receive the measured output current and the measured output voltage, calculate an output power of the intermediate bus converter in dependence upon the measured output current and in dependence upon the measured output voltage, determine an intermediate bus voltage (V IB) to reduce power loss in dependence upon the calculated output power of the intermediate bus converter, and generate a control signal for controlling the converting unit to generate the determined intermediate bus voltage (V IB) so that the intermediate bus converter itself determines an intermediate bus voltage to reduce power loss and performs voltage control to achieve the determined intermediate bus voltage without receiving output current and output voltage measurements from the point of load regulators (202, 203, 204), wherein the controlling unit is operable to determine the intermediate bus voltage (V IB) to reduce power loss by reading an intermediate bus voltage (V IB) from the stored table in dependence upon the calculated output power.