In an embodiment, the present invention includes a latch circuit having a first input to receive a data signal and a second input to receive a clock signal. This latch circuit may have a first pair of transistors including a first transistor gated by the data signal and a second transistor gated by an inverted data signal and a second pair of transistors including third and fourth transistors gated by the clock signal. The first transistor may be coupled to the third transistor at a first inter-latch node and the second transistor coupled to the fourth transistor at a second inter-latch node. A reset circuit may be coupled to the latch circuit to maintain the first and second inter-latch nodes at a predetermined voltage level when the clock signal is inactive.

Providing a reset mechanism for a latch circuit

A data processing system includes first and second power distribution networks to provide power at first and second voltages, and a flip-flop. The second voltage is less than the first voltage. The flip-flop includes a master latch with a power node connected to the first power distribution network, a data signal input, and an output signal output that is driven at the first voltage, and a slave latch with a power node connected to the first power distribution network, an input coupled to the output of the master latch, a slave latch output signal output that is driven by the first voltage, and a feedback circuit with a first latch inverter having a power node connected to the second voltage, an input coupled to the master latch output, and an output terminal to provide an output signal that is driven by the second voltage.

Low swing flip-flop with reduced leakage slave latch

A CMOS cell incorporated on an integrated circuit including a PMOS transistor and an NMOS transistor. The current terminals of the PMOS and NMOS transistors are coupled in series between a lower voltage supply rail and a reference rail. The well connection of the PMOS transistor is coupled to an upper voltage supply rail having a voltage level greater than the lower voltage supply rail. The CMOS cell has low voltage swing and low leakage current to reduce power consumption. A second PMOS and NMOS transistor pair may be included and coupled in similar manner and to the first PMOS and NMOS pair to form a non-inverting cell. The PMOS transistors may be implemented in an N-well that is conductively tied to the upper supply voltage rail to avoid isolation barriers. The cell may be used in a clock tree to significantly reduce power consumption of the integrated circuit.

Low leakage CMOS cell with low voltage swing

In one example, the apparatus includes a first AND gate, a second AND gate, a first NOR gate, a second NOR gate, a third NOR gate, a first inverter, and a second inverter. The first AND gate output is coupled to the first NOR gate first input. The first NOR gate output is coupled to the second NOR gate first input. The second NOR gate output is coupled to the first NOR gate second input. The first inverter output is coupled to the first AND gate second input and the second NOR gate second input. The second AND gate first input is coupled to the first inverter output. The third NOR gate first input is coupled to the second NOR gate output. The third NOR gate second input is coupled to the second AND gate output. The second inverter output is coupled to the second AND gate second input.

Low-area low clock-power flip-flop

A shift register has a first latch and a second latch as well as a first output circuit and a second output circuit. The first latch and the second latch are connected in series. The latches are designed to adopt a signal state present at the data inputs of said latches when in a transparent state and to maintain the adopted signal state when in a non-transparent operating state. Clock inputs of the latches are connected in such a way that the second latch is in the transparent operating state when the first latch is in the non-transparent operating state, and vice versa. The first output circuit is designed to provide, when the first latch is in the transparent operating state, a predetermined level at a first shift register output of the shift register, said level being independent of the signal state present in the first latch, and to provide, when the first latch is in the non-transparent operating state, a level which is dependent on the signal state stored in the first latch. The second output circuit is designed to provide, when the second latch is in the transparent operating state, a predetermined level at a second shift register output of the shift register, said level being independent of the signal state present in the second latch, and to provide, when the second latch is in the non-transparent operating state, a level which is dependent on the signal state stored in the second latch.

Shift register and one-from-many shift register

The invention provides a flip-flop. In one embodiment, the flip-flop receives a low swing clock signal, and comprises a first NMOS transistor, a first latch circuit, a second NMOS transistor, and a second latch circuit. The low swing clock signal is inverted to obtain an inverted low swing clock signal. The first NMOS transistor is coupled between a receiving node and a first node, and has a gate coupled to the inverted low swing clock signal. The first latch circuit is coupled between the first node and a second node. The second NMOS transistor is coupled between the second node and a third node. The second latch circuit is coupled between the third node and a fourth node, and generates an output signal on the fourth node.

Jia-Yi Xu

Papers

Flip-flop for low swing clock signal