A latch has a first mode in which the latch functions as a dynamic latch and a second mode in which the latch functions as a static latch. The latch has a feedback circuit that in turn has two parallel switchable loads. The first load is responsive to a data input signal of the latch in the first mode and disabled in the second mode. The second load is responsive to a clock signal in the second mode and disabled in the first mode. The switchable loads being in parallel provides for the ability to select the feedback that is better for the particular mode of operation. The first and second switchable loads can be optimized for the particular mode of operation that will use it.

This invention applies illustratively to a horizontal driving circuit for a liquid crystal display device, and to a liquid crystal display device utilizing that horizontal driving circuit. With a CMOS latch cell 12 disconnected from power supplies VDD2 and VSS2, the input of the latch cell 12 is connected to an upstream circuit 51 so as to set corresponding data on the cell. Then with the input of the CMOS latch cell 12 disconnected from the upstream circuit 51, the power supplies VDD2 and VSS2 to the CMOS latch cell 12 are switched on to level-shift the data set on the latch cell 12.

A data holding circuit includes a first data holding unit, a second data holding unit and a selection unit. In the first data holding unit, a probability of a soft error at a time when input data has a first level is lower than a probability of a soft error at a time when the input data has a second level. In the second data holding unit, a probability of a soft error at a time when the input data has the second level is lower than a probability of a soft error at a time when the input data has the first level. The selection unit selects an output from the first data holding unit when the input data has the first level, and selects an output from the second data holding unit when the input data has the second level.

A semiconductor integrated circuit according to the present invention comprises a latch circuit, a retaining circuit, and a feedback circuit, wherein the latch circuit inputs therein an input data signal, a clock signal and a feedback signal and outputs an output data signal, the retaining circuit retains the output data signal, and the feedback circuit inputs therein the input data signal and the output data signal to thereby generate the feedback signal based on logic combinations of the input data signal and the output data signal, and an internal operation of the latch circuit is turned on/off by means of the feedback signal.

A storage unit capable of retaining data during sleep mode. The storage unit includes a first latch composed of first and second inverters and a second latch composed of the first inverter and a third inverter, in which the first and second inverters have different threshold voltages. The first inverter comprises an input terminal coupled to a write port and an output coupled to a read port. The second inverter comprises an input terminal coupled to the read port and an output terminal coupled to the write port. The third inverter comprises an input terminal coupled to the write port and an output terminal coupled to the read port.