Abstract: A semiconductor circuit includes an operational amplifier, a voltage drop circuit, and a switch. The operational amplifier has an output terminal connected to an active element that produces a load drive current. A reference voltage is input to the non-inverting input of the operational amplifier. The voltage drop circuit drops a voltage outputted from the operational amplifier. The switch applies a voltage corresponding to a predetermined current flowing when the active element is on to the inverting input of the operational amplifier in a first interval in which the active element is on in response to a predetermined voltage from the operational amplifier. The switch allows the voltage dropped by the voltage drop circuit to be input to the inverting input in a second interval in which the active element is off, thereby shortening a time period until the load drive current starts to flow.

Abstract: A semiconductor circuit includes an operational amplifier, a voltage drop circuit, and a switch. The operational amplifier has an output terminal connected to an active element that produces a load drive current. A reference voltage is input to the non-inverting input of the operational amplifier. The voltage drop circuit drops a voltage outputted from the operational amplifier. The switch applies a voltage corresponding to a predetermined current flowing when the active element is on to the inverting input of the operational amplifier in a first interval in which the active element is on in response to a predetermined voltage from the operational amplifier. The switch allows the voltage dropped by the voltage drop circuit to be input to the inverting input in a second interval in which the active element is off, thereby shortening a time period until the load drive current starts to flow.

Abstract: A phase locked loop circuit includes a phase comparator, a loop filter, a controlled oscillator, a limiter, a frequency divider, an unlock detecting circuit and a switch. The phase comparator compares an index signal and a reference signal. The loop filter smoothes an output signal of the phase comparator. The controlled oscillator oscillates at a frequency in accordance with an output signal of the loop filter. The limiter connected between an output of the phase comparator and an input of the controlled oscillator. The limiter limits the level of a signal passing therethrough at a predetermined range. The frequency divider divides an output signal of the controlled oscillator and generates the reference signal. The unlock detecting circuit outputs the unlocking of a phase lock based on the index signal and the reference signal. The switch shuts up an output signal of the loop filter based on an unlock detecting signal.

Abstract: A phase locked loop circuit includes a phase comparator, a loop filter, a controlled oscillator, a limiter, a frequency divider, an unlock detecting circuit and a switch. The phase comparator compares an index signal and a reference signal. The loop filter smoothes an output signal of the phase comparator. The controlled oscillator oscillates at a frequency in accordance with an output signal of the loop filter. The limiter connected between an output of the phase comparator and an input of the controlled oscillator. The limiter limits level of a signal passing therethrough at a predetermined range. The frequency divider divides an output signal of the controlled oscillator and generates the reference signal. The unlock detecting circuit outputs the unlocking of a phase lock based on the index signal and the reference signal. The switch shuts up an output signal of the loop filter based on an unlock detecting signal.

Abstract: A read-only memory includes a semiconductor substrate; a memory cell matrix which is formed on the semiconductor substrate; and word and bit lines which define the locations of the memory cell matrix. The memory cell matrix includes field effect transistors, each of which turns off when accessed or addressed; and conducting regions, which keep conductive state all the time. Binary data stored in the memory cell matrix are determined by detecting current flowing through the selected bit line.

Abstract: A read-only memory includes a semiconductor substrate; a memory cell matrix which is formed on the semiconductor substrate; and word and bit lines which define the locations of the memory cell matrix. The memory cell matrix includes field effect transistors, each of which turns off when accessed or addressed; and conducting regions, which keep conductive state all the time. Binary data stored in the memory cell matrix are determined by detecting current flowing through the selected bit line.

Abstract: A read-only memory includes a semiconductor substrate; a memory cell matrix which is formed on the semiconductor substrate; and word and bit lines which define the locations of the memory cell matrix. The memory cell matrix includes field effect transistors, each of which turns off when accessed or addressed; and conducting regions, which keep conductive state all the time. Binary data stored in the memory cell matrix are determined by detecting current flowing through the selected bit line.

Abstract: A semiconductive device which comprises a gate insulating film composed of a metal oxide film, source/drain electrodes, and metal silicide layers formed on the source/drain regions is described.

Abstract: In a process of fabricating a semiconductor device, an amorphous semiconductor layer is formed on a substrate, densified by heat-treatment, and is subjected to further heat-treatment to be changed into a polycrystalline semiconductor layer. A MOS transistor can be formed using the polycrystalline semiconductor layer.