Memory circuitry with dynamic power control

Circuits and techniques for operating a memory circuit are disclosed. A disclosed circuit includes a memory circuit and a sleep circuit with an output terminal coupled to the memory circuit. The sleep circuit is operable to receive a control signal and further operable to place the memory circuit in different modes of operation. The memory circuit may be placed in either a first mode of operation, a second mode of operation or a third mode of operation based at least partly on the control signal. An input terminal of the sleep circuit is coupled to an output terminal of the control circuit. The control circuit is operable to receive an enable signal and is operable to supply the control signal to the sleep circuit at first, second and third voltage levels during the first, second and third modes of operation, respectively, based on the enable signal and a clock signal.