Controlling a bitline bias voltage by sensing the bitline bias voltage,
modifying a bitline bias control signal in accordance with the sensed
bitline bias voltage, and controlling the bitline bias voltage in
accordance with the modified bitline bias control signal. The modifying
the bitline bias control signal is carried out by enabling a pull up
circuit and disabling a pull down circuit in response to a first control
signal and disabling the pull up circuit and enabling the pull down
circuit in response to a second control signal.