A circuit includes a power management circuit and a memory circuit. The power management circuit is configured to receive a first control signal and a second control signal, and to supply a first supply voltage, a second supply voltage and a third supply voltage. The first control signal has a first voltage swing, and the second control signal has a second voltage swing different from the first voltage swing. The first control signal causes the power management circuit to enter a power management mode having a first state and a second state. The memory circuit is coupled to the power management circuit, and is in the first state or the second state in response to at least the first supply voltage supplied by the power management circuit.