Abstract: One embodiment provides a piezoelectric vibrator driving circuit for driving a piezoelectric vibrator, the piezoelectric vibrator having an equivalent circuit in which an LC series resonance circuit, an equivalent resistor Rx connected in series thereto and a damping capacitor Co connected in parallel to them are provided, the driving circuit is configured: to detect a driving current Iz flowing through the entire piezoelectric vibrator; to detect a damping current Iy flowing through the damping capacitor Co; to calculate a series resonance current Ix flowing through the LC series resonance circuit by subtracting the detected damping current Iy from the detected driving current Iz; and to perform a phase adjustment so that a phase difference between the calculated series resonance current Ix and a driving voltage Ve to be applied to the piezoelectric vibrator becomes approximately 0.

Abstract: One embodiment provides a piezoelectric vibrator driving circuit for driving a piezoelectric vibrator, the piezoelectric vibrator having an equivalent circuit in which an LC series resonance circuit, an equivalent resistor Rx connected in series thereto and a damping capacitor Co connected in parallel to them are provided, the driving circuit is configured: to detect a driving current Iz flowing through the entire piezoelectric vibrator; to detect a damping current Iy flowing through the damping capacitor Co; to calculate a series resonance current Ix flowing through the LC series resonance circuit by subtracting the detected damping current Iy from the detected driving current Iz; and to perform a phase adjustment so that a phase difference between the calculated series resonance current Ix and a driving voltage Ve to be applied to the piezoelectric vibrator becomes approximately 0.

Abstract: A voice recording/playback apparatus includes a head unit which records a voice signal in a recording medium and for playing back a recorded voice signal from the recording medium. A playback head amplifier unit amplifies a playback signal output from the head unit. A voice output unit outputs a voice in accordance with the playback signal amplified by the playback head amplifier unit. A muting switch is provided between the playback head amplifier unit and the voice output unit. The muting switch cuts off a connection between the playback head amplifier unit and the voice output unit when a voice recording mode is performed by the head unit.

Abstract: A switching regulator includes an oscillation circuit for generating a triangular waveform signal having a predetermined frequency, a comparator compares the triangular waveform signal generated by the oscillation circuit with a voltage control signal commensurate with a voltage to be output so as to generate a pulse signal which goes high or low depending on a result of the comparison, and a driving circuit for selecting a portion of the triangular waveform signal generated by the oscillation responsive to the pulse signal generated by the comparator, so as to generate the drive signal for driving the switching element.

Abstract: A motor drive circuit 1 is driven by a DC power source 2 connected to power source terminals Tv1, Tv2 and has a first drive transistor Q1 for controlling a drive current supplied to a first terminal Tm1 of a motor from the DC power source 2, a second drive transistor Q2 for supplying current drawn from the first terminal Tm1 of the motor 3 to a ground, a third drive transistor Q3 for controlling a drive current supplied to a second terminal Tm2 of the motor 3 from the DC power source 2, a fourth drive transistor Q4 for drawing current from a second terminal Tm2 of the motor 3, a drive control circuit 4 for controlling the operation of the motor 3 by controlling the drive transistors Q1 through Q4 in response to a first and second control signal supplied to a first and second control terminal Tc1, Tc2, a first control transistor Qc1 having the same polarity as, and connected in parallel to and in the reverse direction of, the second drive transistor Q2 and a second control transistor Qc2 having the same polari

Abstract: A first capacitor is charged by a driving current. A second capacitor is charged by a driving current. A first discharging transistor discharges the first capacitor in accordance with a charged voltage of the second capacitor. A second discharging transistor discharges the second capacitor in accordance with a charged voltage of the first capacitor. The oscillation circuit generates an oscillation signal in accordance with the charged voltages of the first and second capacitors. An oscillation restarting circuit, when the first and second discharging transistors simultaneously perform discharging and thus oscillation stops, causes the discharging of the second discharging transistor to stop, and thereby, restarts the oscillation.

Abstract: An amplifier system includes a constant current unit which produces a constant current in response to a source voltage from a source voltage terminal. An emitter follower unit has a base, an emitter and a collector, an input signal being supplied to the base, the emitter being connected to the constant current unit, the source voltage being supplied to the collector, the emitter follower unit producing an output signal at the emitter in response to the input signal. A current regulating unit regulates the constant current in response to a collector current fed into the collector of the emitter follower unit, so that the constant current is fed from the emitter of the emitter follower unit into the constant current unit.

Abstract: The semiconductor types of first and second semiconductor type transistors are different from one another and the two transistors are connected in series. An input signal is supplied to each of the bases of the first and second transistors. Each of the collector electric currents of the first and second transistors are thus controlled. An output is provided from the inter-connection point of the first and second transistors. A third transistor supplies the collector electric current which is 1/K.sub.1 times the collector electric current of the second transistor, where K.sub.1 is the current-mirror ratio between the second and third transistors. A fourth transistor has the collector and base connected with one another. The fourth transistor supplies an electric current according to the collector electric current of the third transistor. A fifth transistor has the base electric current controlled by the base electric current of the fourth transistor.

Abstract: A sensor IC generates a voltage according to magnetic flux density of an applied magnetic field. The sensor IC includes a plurality of Hall sensors having an identical shape formed adjacent to each other in a semiconductor chip, each of the Hall sensors generating a sensor output voltage which includes a Hall output voltage component in proportion to the magnetic flux density. The sensor IC further includes a plurality of differential amplifiers having an identical circuit formed adjacent to each other in the semiconductor chip, each of the differential amplifiers multiplying the sensor output voltage produced from a corresponding one of the Hall sensors by a given gain. In the sensor IC, by a summing circuit, output signals produced from the plurality of differential amplifiers are summed.

Abstract: A semiconductor device includes a plurality of groups of transistor elements which are formed on a single semiconductor chip, each group having a first pair of transistor elements which are arranged so as to be symmetrical about a point and a second pair of transistor elements which are arranged, in a direction perpendicular to a direction in which the first pair of transistor elements are arranged, so as to be symmetrical about the point. The first pair of transistor elements in all the plurality of groups are connected in parallel so that a first transistor is formed of the first pair of transistor elements, and the second pair of transistor elements in all the plurality of groups are connected in parallel so that a second transistor is formed of the second pair of transistor elements, the first transistor and the second transistor being paired.