Hitachi, Ltd.

Oki Semiconductor Co., Ltd.

Hitachi Microcomputer Engineering, Ltd.

Hitachi Microcomputer System, Ltd.

Hitachi Video and Information System, Inc.

Hitachi Ome Electronic Co., Ltd.

Kunio Seki

Yasuhiko Kokami

Toshiyuki Tsunoda

Ritsuji Takeshita

Kunihiro Kawauchi

Yuichi Ohkubo

Yukio Suzuki

Yoshio Sakamoto

Hirotaka Mochizuki

Makoto Goto

Susumu Takahashi

Kenichi Onda

Masatoshi Morikawa

Yasuhiro Nunogawa

Soichiro Ogawa

Makoto Kobayashi

Kenji Kawabata

Motohiro Sugino

Ryuichi Ikeda

Susumu Iijima

Kazutaka Inoue

Ryozo Kontani

Norihisa Katoh

Hiroyuki Kikuta

The present disclosure provides a brushless motor driving circuit capable of clamping an output voltage at a proper voltage, even when a power source voltage changes. Namely, a pre-driver circuit generates a voltage for driving a brushless motor from a source voltage by turning on/off first and second PMOS transistors and first and second NMOS transistors in an H bridge circuit of a drive voltage generating circuit, and applies the voltage to a coil of the brushless motor. A first clamp circuit turns on/off the first NMOS transistor on the ground side so that the output voltage at a first output terminal becomes equal to or lower than the source voltage. A second clamp circuit turns on/off the second NMOS transistor on the ground side so that output voltage at a second output terminal becomes equal to or lower than the source voltage.

Brushless motor driving circuit

A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.

Semiconductor integrated circuit for brushless motor drive control and brushless motor drive control apparatus

A motor drive method and apparatus for reducing noise of a motor. The motor drive apparatus includes first, second and third half bridge circuits. Each of the first, second and third half bridge circuits includes a first transistor which is adapted to form a current path between a first operational potential and an output terminal thereof and a second transistor which is adapted to form a current path between a second operational potential and the output terminal thereof. Each of the output terminals are connected to the corresponding drive coil of a motor. Each of the first and second transistors includes a control terminal to which a control signal is supplied. The motor drive apparatus detects a counter-induced voltage of the drive coil corresponding to the second half bridge circuit by supplying control signals to the first and second transistors thereof for making each current path therein a non-conducting state, and for forming current paths in the first transistor of the first half bridge circuit and in the second transistor of the third half bridge circuit respectively. Further the motor drive apparatus cuts off the current path of the first transistor in the first half bridge circuit, forms it and cuts it off again by supplying a control signal thereto after start of supplying a control signal for forming the current path of the first transistor in the second half bridge circuit. A control signal for forming the current path is supplied to the control terminal of the second transistor in the third half bridge circuit.

Method and apparatus for driving an electric motor

A motor speed regulating circuit includes a speed signal generator for generating a speed signal having a frequency proportional to the speed of the motor, synchronously with the rotation of the motor. A time difference detector is used for detecting a time difference between the period of the speed signal and a predetermined standard time. A control voltage generator is used for generating a speed control voltage to be applied to the motor in accordance with a detected time difference and feedback-controlling the speed of the motor in accordance with the standard time. A starter is used for starting the motor after the motor is stopped. The motor can be reliably restarted after it has been stopped.

Motor speed regulating circuit with starter and storage medium drive

A semiconductor integrated circuit device incorporates a voltage step-up (boost) circuit which produces a stepped-up (boosted) voltage higher than the power voltage based on a periodic pulse signal generated internally or supplied from the outside. The stepped-up voltage is supplied to the emitter of a pnp driving transistor that produces a drive current for the output transistor on the voltage source side which is the one of a pair of npn output transistors in push-pull configuration. The voltage step-up circuit has its current supply capacity varied in response to the current flowing through the output transistor or driving transistor.

Semiconductor integrated circuit device

An information processing apparatus employs a liquid crystal display and a fluorescent lamp for backlighting the screen of the liquid crystal display. A lighting circuit for supplying alternating current lighting power to the fluorescent lamp receives input power from either a commercial alternating current power source or from a direct current battery. The level of the lighting power supplied to the fluorescent lamp is determined based upon a determination of whether the input power is being supplied from the commercial power source or from the battery.

Information processing apparatus including a control circuit for

When a current that flows into a power output element is greater than a predetermined value, pulse width-modulated signals are formed which vary in inverse proportion to the current value in order to drive the power output element. When an excess current flows into the power output element, therefore, the power output element is allowed to intermittently operate for only short periods of time, and the current can be decreased during the current-limiting operation.

Power switching circuit

An amplifier comprises an amplifier circuit for amplifying an input signal and a supply voltage detector for controlling the operation of the amplifier circuit. The supply voltage detector has hysteresis characteristics as to a first threshold voltage and a second threshold voltage which are different from each other in order to detect the magnitudes of the supply voltage. The amplifying operation of the amplifier circuit is controlled as to the start-up and turn-off operation thereof by an output signal of the supply voltage detector.

Amplifier

Two output transistors constituting a push-pull output amplifier circuit are connected in series between a power supply and a grounded point, and an output terminal is disposed at a point where the two output transistors are commonly connected. An operation detector circuit detects the operation of one output transistor. A level detector circuit detects a d-c voltage level at the output terminal. The two output transistors are driven by a drive circuit in a push-pull manner. The output of the operation detector circuit and the output of the level detector circuit control the drive circuit via a control circuit. When the operation detector circuit detected the fact that the operation of one output transistor has deviated beyond a predetermined detection level, the control circuit works to confine the operation of the abovementioned output transistor within a predetermined restriction level via the drive circuit. The power loss in the restriction level is smaller than the power loss in the detection level. During a period in which the output terminal is short-circuited to the grounded point in a d-c manner, the level detector circuit so controls the control circuit that the operation of the abovementioned one output transistor is confined within the restriction level.

Transistor power amplifier circuit

A two signal amplifying system is constructed of first and second BTL amplifiers each including a phase splitter and first and second push-pull output circuits. In each of the first and second push-pull output circuits, output transistors are connected between a power source and output terminals, and detectors for detecting the operating states of said transistors are connected with the output transistors constituting the aforementioned first and second push-pull output circuits, respectively. The outputs of those two detectors are fed to a control circuit. The output of the control circuit renders the two output transistors nonconductive in case at least one of the two output transistors deviates from a predetermined operating range.

Two signal amplifying system

A semiconductor integrated circuit device for an amplifier circuit including a semiconductor substrate in which an audio amplifier circuit is formed in an integrated circuit form, at least one first wire bonding pad which is formed on said semiconductor substrate to ground said audio amplifier circuit, and an externally connecting terminal which is provided being separated away from said semiconductor substrate and which is electrically connected to said first wire bonding pad via a metal wire, wherein the improvement comprises a wire bonding pad for the substrate which is formed on said semiconductor substrate being separated away from said first wire bonding pad, and which grounds said semiconductor substrate, and a metallic connector wire which electrically connects said wire bonding pad for the substrate to said externally connecting terminal.

Integrated circuit with at least three ground pads

A push-pull output circuit which is capable of producing a relatively-high maximum output voltage without the use of a bootstrap capacitor provides positive and negative half cycle output circuits which are constructed as inverted Darlington output circuits to which current mirror circuits and level shifting elements are coupled. As a result, the distortion factor of an open loop characteristic in the push-pull output circuit is improved.

Push-pull output circuit

An acoustic monolithic IC, which is enabled by a simple modification of the external circuit thereof to realize either the amplification of the left and right channels of stereophonic signals or the application to a balanced transformer-less (BTL) amplifier circuit, is composed of first and second differential amplifier circuits each having non-inverting and inverting inputs and of first and second amplifier output circuits each having non-inverting and inverting inputs. The first differential amplifier circuit has its non-inverting and inverting inputs led as the first and second input terminals of the acoustic monolithic IC to the outside thereof whereas the second differential amplifier circuit has its non-inverting and inverting inputs led as the third and fourth input terminals of the acoustic monolithic IC to the outside thereof. The output signals of the first and second differential amplifier circuits are impressed upon the non-inverting inputs of the first and second amplifier output circuits, respectively. The inverting inputs of the first and second amplifier output circuits are led as first and second feedback terminals to the outside of the acoustic monolithic IC so as to determine the gains and output DC levels of those amplifier output circuits. The output terminals of the first and second amplifier output circuits are led as the first and second output terminals of the acoustic monolithic IC to the outside thereof.

Growing community of inventors

Hinode, Japan

Kunio Seki