A semiconductor substrate support for supporting a semiconductor substrate in a plasma processing chamber includes a heater array comprising thermal control elements operable to tune a spatial temperature profile on the semiconductor substrate, the thermal control elements defining heater zones each of which is powered by two or more power supply lines and two or more power return lines wherein each power supply line is connected to at least two of the heater zones and each power return line is connected to at least two of the heater zones. A power distribution circuit is mated to a baseplate of the substrate support, the power distribution circuit being connected to each power supply line and power return line of the heater array. A switching device is connected to the power distribution circuit to independently provide time-averaged power to each of the heater zones by time divisional multiplexing of a plurality of switches.