A clock circuit includes a latch circuit, a memory state latch circuit, a first inverter, a memory state trigger circuit and a second inverter. The latch circuit is configured to latch an enable signal, and to generate a latch output signal based on a first clock signal and a first output clock signal. The memory state latch circuit is configured to latch a second output clock signal responsive to a third output clock signal. The first inverter is configured to generate the first output clock signal responsive to the third output clock signal. The memory state trigger circuit is configured to generate the second output clock signal responsive to the latch output signal. The second inverter is configured to generate the first clock signal responsive to a second clock signal, and configured to control the latch circuit and the memory state trigger circuit based on the first clock signal.