Seiko Instruments Inc

Ablic Inc.

Sii Semiconductor Corporation

Seiko Instruments & Electronics Ltd.

Hiroshi Mukainakano

Yukito Kawahara

Satoshi Machida

Sadashi Shimoda

Takayuki Takashina

Yoshikazu Kojima

Minoru Sudo

Masahiro Yokomichi

Atsushi Sakurai

Masato Higashi

Kazuaki Sano

Toshiyuki Koike

Eiichi Iwanami

Masanao Hamaguchi

Takao Nakashimo

Shinichi Yoshida

Koichi Yamasaki

Kimio Shibata

Koichi Yamazaki

Kazunari Sugiura

Takayuki Takahashi

Kawahara Yukito

Provided is a battery monitoring system that has a high level of safety even under a state in which characteristics of a reference voltage circuit are deteriorated. The battery monitoring system has a configuration in which: a reference voltage of a first battery monitoring IC is monitored by a second battery monitoring IC; and the second battery monitoring IC outputs, when detecting that the reference voltage reaches a value falling outside a predetermined range, a signal indicating an abnormality of the reference voltage to the first battery monitoring IC, and the first battery monitoring IC stops monitoring of a battery when the signal indicating the abnormality of the reference voltage is input to the first battery monitoring IC.

Battery monitoring system

Provided is a battery state monitoring circuit and a battery device capable of predicting a state of charge of a secondary battery with high accuracy. The battery state monitoring circuit includes a pseudo-equivalent circuit of the secondary battery, and causes a current flowing through a sense resistor to flow to the pseudo-equivalent circuit of the secondary battery, to thereby measure a pseudo-open circuit voltage of the secondary battery.

Battery state monitoring circuit and battery device

The present invention relates to an improvement in the safety and a reduction in a current consumption in a battery device which is capable of calculating the remaining amount of a lithium ion secondary battery. If the charging and discharging current becomes equal to or lower than a given value, circuits including a current monitoring circuit operate so as to reduce the current consumption. In this situation, the current monitoring circuit stops to function. A control circuit is connected with a differentiating circuit, and if a voltage between both ends of the sense resistor changes, a charging and discharging current monitoring circuit is again operated. With the above solving means, the current consumption can be suppressed, and a precision in the current monitor can be enhanced.

Battery state monitoring circuit having differentiating circuit

A delay circuit includes a capacitor, a charging/discharging control circuit receptive of an input signal for controlling at least one of the charging and the discharging of the capacitor to set a delay time in accordance with a capacitance value of the capacitor, and a comparing circuit for comparing a voltage at a first terminal of the capacitor with a first reference voltage to produce an output signal which becomes inverted after the delay time when the voltage at the first terminal of the capacitor crosses over the first reference voltage during one of charging and discharging of the capacitor, and comparing a voltage at the first terminal of the capacitor with a second reference and producing an output signal which becomes inverted when the voltage at the first terminal of the capacitor is higher than the second reference voltage so that the delay time is reduced when the first terminal of the capacitor becomes short-circuited to an abnormally high voltage level.

Delay circuit

By supplying a positive power supply of the operational amplifier from a switching regulator using an input voltage of the operational amplifier as its reference voltage, even if the bias ratio is varied, the ratio of the positive power supply voltage of the operational amplifier to an output voltage of the operational amplifier is always constant, and thus, there is an effect that a liquid crystal display device with low power consumption can be implemented independently of the panel.

Power supply circuit for liquid crystal display

In a battery state monitoring circuit including a voltage regulator therein, power supply of the voltage regulator is applied from a higher voltage either of a battery or a charger. Also, when the output voltage of the voltage regulator becomes lower, there is structured such as to provide a voltage detecting circuit that sends a signal to the micro-computer.

A charge/discharge control circuit is provided for an electric power source apparatus in which a service life is prolonged. A voltage dividing circuit, an overcharge voltage detection circuit, an overdischarge voltage detection circuit and a control circuit are connected in parallel to a secondary cell which is an electric power source, wherein the control circuit detects a condition of the secondary cell from the overcharge/overdischarge voltage detection circuits and outputs a signal Vs for controlling a power supply to an external equipment and a charge by an external power source and controls a switching element provided in series with the voltage dividing circuit and reduces a current which flows through the voltage dividing circuit.

Charge/discharge control circuit and chargeable electric power source apparatus

In a battery state monitoring circuit including a voltage regulator therein and capable of controlling an internal circuit with a signal from a microcomputer, a circuit is provided in which the control of the internal circuit is available with the signal from the microcomputer in the case where the output of the voltage regulator is normal, and the signal of the internal circuit is decided regardless of the signal from the microcomputer in the case where the output of the voltage regulator is floating or in GND level.

Overcharge/overdischarge detecting circuit having current detecting means with latch function and chargeable electric power source apparatus

A charge and discharge control circuit and a chargeable power supply unit incorporating the charge and discharge control circuit are provided with a current detecting element capable of detecting low currents with high accuracy and detecting high currents wuthout excessive power dissipation. The charge and discharge control circuit detects a charge and discharge state of a secondary cell and controls the charging and discharging of the secondary cell in accordance with the detected state. A switch circuit and the current detecting element are connected in series with the secondary cell. The current detecting element has an adjustable resistance value which is varied in accordance with the value of a current flowing therethrough, and comprises a first resistor and a second resistor connected in series, and a switch element connected in parallel to the second resistor. When current is low, the switch is operated so that current flows through the first and second resistors so that increased detection accuracy is possible. When is high, the switch is operated so that current flows only through the first resistor so that detection accuracy remains high but power dissipation is not increased.

Charge and discharge control circuit with function detecting charge and

Overcharge/overdischarge detecting circuit having a reset means and

A charge/discharge control circuit has a voltage detecting circuit for detecting at least one of an over-charge state, an over-discharge state and an over-current state of a battery, a control circuit for receiving an output signal of the detecting circuit and outputting a signal for controlling the charging and discharging of the battery, and an activating circuit connected to the control circuit for selectively activating the control circuit according to an output signal of the detecting circuit so as to limit the power consumption of the charge/discharge control circuit by operating the control circuit only when one of an over-charge state, an over-discharge state and an over-current state of the electric power source is detected.

Charging and discharging control circuit and charging type power supply

A charge/discharge control circuit is provided which prevents an abnormally high charging voltage from damaging a secondary cell. The charge/discharge control circuit has an overcharge detecting circuit for detecting whether the secondary cell is in an overcharged state by comparing a divided output voltage of the secondary cell with a reference voltage, a delay circuit for outputting a delayed version of an output of the overcharge detecting circuit delayed by a predetermined delay time, and a high voltage detecting circuit for detecting whether the secondary cell is in a high voltage supplying state by detecting whether a voltage of the secondary cell is more than a predetermined level higher than the overcharge detecting voltage detected by the overcharge detecting circuit. The switch circuit is turned OFF to stop charging of the secondary cell when either the overcharge state or the high voltage supplying state is detected in response to outputs of the delay circuit and the high voltage detecting circuit.

Charge and discharge control circuit

An improved charge pump circuit includes one switch element driven by a ramp waveform to precisely control the output voltage. The circuit includes a switch group having one or more switch elements for transferring a charge to one or more capacitors, a feedback circuit having an error amplifier for amplifying a difference between a divided output voltage and a reference voltage, a compensation circuit for phase compensating the feedback network, an oscillator for generating the ramp waveform, and a control circuit for driving the one or more switch elements. At least one of the switch elements has a resistance that can be adjusted externally and is driven by the ramp waveform such that its resistance varies with time. Accordingly, the charge transferred from a power source to the one or more capacitors can easily be adjusted. When the charge transferred is small, the on-time of the ramp waveform is short and the average value of the resistance is large. The average resistance of the switch group varies when the voltage of the power source varies, so that an output with a fixed voltage and low ripple voltage can be obtained.

Charge pump circuit

A charge/discharge control circuit for controlling the charging and discharging of a secondary cell has a voltage dividing circuit for dividing an output voltage of the secondary cell, which may comprise plural cells, an overcharge detection circuit for detecting an overcharge state of the secondary cell, an overdischarge detection circuit for detecting an overdischarge state of the secondary cell, and a control circuit for receiving and processing an output signal of the overcharge detecting circuit and the overdischarge detecting circuit and controlling the switch. In a preferred embodiment, an overcharge reference voltage source used for the overcharge voltage detection circuit is used also as an overdischarge reference voltage source for the overdischarge voltage detection circuit.

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Tokyo, Japan

Hiroshi Mukainakano