Mitsumi Electric Company Ltd.

Yukihiro Terada

Akira Ikeuchi

Kenichi Miki

Kazuo Yamazaki

Hidenori Tanaka

Tamiji Nagai

Masaru Takeuchi

Tomomitsu Oohara

Yasuhisa Ishikawa

Hiroshi Nagaoka

Hideaki Adachi

Junji Takeshita

Daisuke Kimura

Shuhei Abe

Yasuhisa Higashijima

Atsushi Watanabe

Kyozo Makime

Kazuhiro Ooshita

Osamu Kawagoe

Toshio Nagai, Legal Representative

Katsuya Sakuma

Seiji Miura

Yoshitaka Onishi

Hiroshi Oya

A charge and discharge circuit and a battery pack, both capable of voluntarily perform proper switching between a charge operation and a discharge operation of a secondary battery according to various situations, are provided. The charge and discharge circuit of a secondary battery is one capable of charging the secondary battery Eby a power source voltage and of supplying power from the secondary battery Eto an external device. Then, the charge and discharge circuit includes a bidirectional regulatorcapable of adjusting an output in both of a charge direction of feeding the current to the side of the secondary battery Eand a discharge direction of feeding the current from the secondary battery Eto the side of the external device, a charge and discharge detecting circuitfor detecting a direction of the current flowing in the secondary battery E, and a switching control circuitfor switching the operation direction of the bidirectional regulatorbased on the detection of the charge and discharge detecting circuit

Charge and discharge circuit of secondary battery and battery pack

Provided is a bidirectional converter which has flexibility to be applicable in various conditions and performs stable switching of operation mode at high efficiency. An electronic device which supplies power in various conditions and operates with excellent efficiency is also provided. An electronic device is provided with a bidirectional converter, which has a reactor and four switches between power supply input terminals and a secondary battery, and a system circuit is supplied with an operation voltage through the bidirectional converter. A status signal indicating the operation status of the system circuit is transmitted to a microcomputer of the bidirectional converter, and based on the status signal, switching of operation mode of the bidirectional converter is controlled.

Bidirectional converter and electronic device

A DC-DC converter includes: an inductance element and a rectifier element connected in series between a voltage input terminal to accept input direct current voltage and a first output terminal; a switching element connected between a connection node of the inductance element and the rectifier element and a reference potential point; and a controlling circuit to form a signal to control on/off of the switching element. The controlling circuit controls on/off of the switching element to control current through the inductance element, and a voltage applied to the voltage input terminal to accept the input direct current voltage is output via a second output terminal as a reference potential of a circuit at a latter stage, so that an output voltage is controllable from a lower to higher voltage than the input direct current voltage without switching step-up and step-down operations.

DC-DC converter and power supply apparatus

A battery protecting circuit is disclosed that includes a negative voltage terminal voltage detecting circuit that detects when a voltage of a negative voltage terminal decreases to less than a predetermined voltage; an abnormality detecting circuit that detects an abnormality in charge/discharge conditions of a battery; a switch that is connected between the battery and the negative voltage terminal, the switch being turned off when the negative voltage terminal voltage detecting circuit detects that the voltage of the negative voltage terminal has decreased to less than the predetermined voltage and when the abnormality detecting circuit detects the abnormality in the charge/discharge conditions of the battery; a delay time reducing circuit that reduces a time period from a time the abnormality in the charge/discharge conditions of the battery is detected to a time the switch is turned off when the voltage of the negative voltage terminal decreases to less than the predetermined voltage; and an output invalidating circuit that invalidates an output of the negative voltage terminal voltage detecting circuit.

Battery protecting apparatus and battery protecting circuit

A thermal head drive circuit drives M number of thermal heads for printing one line and includes a delay unit that applies different time delays to M bits of print data to be supplied to the corresponding M thermal heads. The higher order the odd number thermal heads of the M thermal heads are, the greater are the time delays applied to the corresponding bits of the print data, while the higher order the even number thermal heads of the M thermal heads are, the less are the time delays applied to the corresponding bits of the print data.

Thermal head drive circuit and printer using the same

A battery protection device protects a battery from an abnormal state. The battery protection device includes a detector that detects an abnormality of the battery and outputs an abnormality detection signal when the abnormality is detected. A current is input to an input terminal from outside. A voltage converter converts the current input to the input terminal to voltage and outputs the voltage. A combiner combines the abnormality detection signal with the voltage and outputs a combined signal. A current converter converts the combined signal to a current. An output terminal outputs the current.

Battery protection device, battery protection system using the same, and battery protection method

A battery pack with a charge control function includes a charge protection circuit and a charge control circuit. The charge control circuit turns a discharge control switch on or off to control a discharge current which flows from a secondary battery to a load and also turns a charge control switch on or off to control a charge current which flows from a charger to the secondary battery. When an abnormal voltage is input, the charge control circuit turns the charge control switch on or off to stop the charging of the secondary battery through the charger.

Battery pack with charge control function

A semiconductor device includes a substrate, a well region formed in the substrate, a field effect transistor formed in the well region, and a diffused region, formed across the well region and the substrate for applying back gate potential to the well region, and forming a PN junction together with its periphery. The field effect transistor and the PN junction are connected between terminals for absorbing excess current so that an internal circuit connected to the terminals is protected.

Electrostatic discharge semiconductor protection circuit of reduced area

A monolithic IC package, includes a monolithic IC, a package receiving the monolithic IC, an external connection terminal provided in the package and electrically connected to the monolithic IC by wiring, and protection means for protecting the monolithic IC from the electrostatic discharge, wherein the external connection terminal is used as the protection means.

Monolithic IC package

In a secondary battery protection circuit ( ) for protecting a secondary battery ( ) by controlling, by turning a discharge control switch (FET ) on and off, a discharging current (l) flowing from the secondary battery ( ) through a load ( ) connected between a pair of external connection terminals ( ), a clamping circuit ( ) clamps a control terminal (G ) of the discharge control switch (FET ) into a ground potential when the external connection terminals ( ) are short-circuited.

Secondary battery protection circuit having a clamping circuit including a comparator and a transistor

A plurality of IC chips each having an internal circuit are mounted on a wafer substrate. A plurality of scribe lines are formed on the wafer substrate for separating the IC chips from one another. A plurality of inspection pads are formed on the scribe lines. Each of the inspection pads is connected to the associated internal circuit via a conduction path for inspecting an operation of the associated IC chip.

Semiconductor wafer

A static protection device protects an internal circuit of a semiconductor device from surge voltages. An emitter terminal of the PNP transistor is connected to the input/output terminal, a collector terminal of the PNP transistor is connected to the ground terminal, and the base terminal is left open, to realize the static protection device. In this manner the reverse-biased protection can be maintained with respect to the internal circuit.

Static protection device

A secondary battery protection circuit detects at least one of an over-discharge state, an over-charge state, and an over-current state of a secondary battery and performs an operation in accordance with the detected state. The secondary battery protection circuit comprises a blind time setting circuit constituted by an IC for setting a blind time in accordance with the detected state. The blind time setting circuit has a switching circuit for setting a blind time for a functional test that is shorter than a preset blind time.

Secondary battery protection circuit capable of reducing time for functional test

Semiconductor wafer with scribe lines having inspection pads formed thereon

A head amplifier circuit supplies a writing current, having a direction in accordance with recording information, to a head for recording information on a recording medium. The head amplifier circuit includes a reference voltage generating portion for generating a reference voltage, a constant current generating portion for generating a constant current based on the reference voltage generated by the reference voltage generating portion, and a grounding portion. During one period of time, the constant current generating portion supplies the constant current to a first end of the head and the grounding portion grounds a second end of the head. During another period of time, the constant current generating portion supplies the constant current to the second end of the head and the grounding portion grounds the first end of the head.

Growing community of inventors

Atsugi, Japan

Yukihiro Terada