Integrated circuit well bias circuitry

Well bias circuitry for selectively biasing the voltages of the well areas of an integrated circuit. In one embodiment, the well bias circuitry includes a switching cell located in a row of cells of the integrated circuit for selectively coupling a voltage supply line to a well bias line. The switching cell may include two level shifters, each for providing a voltage to a gate of a coupling transistor to make the coupling transistor non conductive in response to an enable signal. The switching cells may be sequentially coupled such that the coupling transistors of each of the switching cells are not made conductive at the same time so as to reduce inrush current due to changing the well bias from a well bias voltage to a supply voltage. In one example, the switching cells may include delay circuitry for delaying the change in state of the enable signal before being provided to the next switching cell.