Sony Corporation

Mitsumi Electric Company Ltd.

Tamiji Nagai

Kazuo Yamazaki

Tamon Ikeda

Kuniharu Suzuki

Toshitaka Takei

Tadahisa Yamamoto

Kazunori Ozawa

Yoshio Ishigaki

Hidenori Tanaka

Yasuhito Eguchi

Yukihiro Terada

Masaru Hiratsuka

Takayuki Aita

Hitoshi Akiho

Kenji Enomoto

Toshio Nagai, Legal Representative

Shigeki Murayama

Takeshi Matsushita

Susumu Yoshida

Hiroshi Sahara

Yoshisada Okayasu

Sumio Iwase

Kaoru Tomono

Akio Nakamura

Tsutomu Suda

Makoto Kamoshida

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

To reduce power loss during standby. In a switching power supply device using a first power supply circuit () having a small output and a second power supply circuit () having a large output, the first power supply circuit () is continuously kept in an operating state and the second power supply circuit () is started by using an electric power generated in the first power supply circuit ().

Switching power supply device and method of starting the same

A solenoid type switch has at least two driving coils. The driving coils turn off a switch with a current for example an overcurrent that flows in the switch. The driving coils are magnetized or demagnetized by a driving circuit so as to turn on or off the switch. The driving circuit magnetizes or demagnetizes the driving coils in accordance with a control signal supplied from a controlling circuit. Thus, the switch can be turned off with the current that flows in the driving coils.

Switching circuit, switching method, protective device and battery pack

A driving circuit is disclosed. The driving circuit comprises a secondary battery cell having a positive electrode and a negative electrode, first and second N-type field effect transistors each having a gate, a drain, and a source, first and second switching devices, connected between the gates of the first and second N-type field effect transistors and the negative electrode side of the secondary battery cell, for turning on and off the first and second N-type field effect transistors, driving means for controlling the first and second switching devices, first and second output terminals, and a diode having an anode and a cathode.

Driving circuit for field effect transistor

When an output voltage of a secondary battery cell Eis obtained, only SWand SWare turned on. As a result, a capacitor Cis charged by a secondary battery cell E. With a delay of a time period &#xc4;T, SWand SWare turned off. SWand SWare turned on. As a result, electric charges of the capacitor Care moved to a capacitor C. Those operations are repeated until the potential of the capacitor Cbecomes almost equal to the output voltage of the secondary battery cell E. When the potential of the capacitor Cbecomes almost equal to the output voltage of the capacitor C, the potential of the capacitor Cis detected by the voltage detector. A first terminal of the capacitor Cis connected to a ground potential. As a result, the voltage of the secondary battery cell Ecan be stably detected. When the secondary battery cell Eis detected, only SWis turned on. As a result, the capacitor Cis charged by the secondary battery cell E. The potential of the capacitor Cis detected by the voltage detector. The voltage detectoris used in common with the secondary battery cells Eand E. As a result, fluctuations of detected results can be prevented. In addition, using that method, a circuit power can be supplied by the capacitor C

Apparatus for connecting secondary battery cells in series and method for controlling secondary battery cells connected in series

In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Qand Qare arranged between two input terminals of a terminalfor an external power adaptor and a terminalfor a holder and a secondary battery E, respectively. When a control ICdetects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control ICdetects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery Eis charged by the power source of the higher priority.

Charging apparatus and charging method

In the case of charging by a charging apparatus having a plurality of input terminals to which external power sources for charging a secondary battery are inputted, it is prevented that a current of the inputted power source is outputted to the outside from the other input terminals for charging which are not used. If there are inputs from a plurality of input terminals, the input power sources are controlled so that the battery is optimally charged. pnp-type transistors Qand Qare arranged between two input terminals of a terminalfor an external power adaptor and a terminalfor a holder and a secondary battery Erespectively. When a control ICdetects an input power voltage of one of the transistors, the transistor on the detected side is turned on. If the control ICdetects both input power voltages, a priority is allocated under predetermined conditions and the secondary battery Eis charged by the power source of the higher priority.

Charging apparatus and method for a secondary battery of a portably electronic device

A commercially available power source is rectified by a diode bridge and a capacitor and supplied to a transformer via a terminal. One end of a primary coil is connected to the terminal and the other end is connected to a switching device. One end of a feedback coil is connected to the switching device and the other end is connected to the terminal. A negative feedback circuit is provided between the switching device and the terminal. A rectifying circuit comprising a diode and a capacitor is provided on a secondary coil. A node of the coil and the capacitor is connected to the terminal via a resistor. In detecting circuits, a voltage across the terminal is detected and a current across the resistor is detected. When the detected voltage and current are equal to predetermined values, a control signal is supplied to a feedback circuit.

Switching power supply using controlled negative feedback in series with a switching device and responsive to the voltage and/or current to a load

Switching power supply using controlled negative feedback in series with a switching device and responsive to the voltage and or current to a load

A battery pack BP having terminals T , T , and T , a detecting circuit, a signal generating circuit, a temperature, voltage, and current detecting circuit, a switching circuit, and a secondary battery connected to the switching circuit. A first external signal generating unit may be connected to terminals T and T and a second external signal generating unit may be connected to terminals T and T . The detecting circuit detects whether the first or second external signal generating units has been connected. In so doing, the detecting circuit may detect an impedance of the first external signal generating unit and may detect a terminal voltage of the second external signal generating unit. The on/off operations of the switching circuit SW may be controlled in accordance with the detection result.

Battery pack and signal transmission system

To reduce errors and decrease loss, the detecting range of current is enlarged and the current is independently detectable. A rectified voltage and a rectified current are supplied from an input terminal. Resistors and are serially connected between the input and output terminals. A load is connected to the output terminal. Between an emitter and collector of the transistor are resistor and a constant current detecting circuit The transistor base is connected to a control circuit that controls the transistor switching operations. The constant current detecting circuit detects current from the voltage across resistor A current detecting circuit detects current from the voltage across resistor A signal is supplied to the control circuit when the constant current detecting circuit detects small current. The control circuit supplies a signal to the transistor base that increases transistor impedance.

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Kanagawa, Japan

Tamiji Nagai