Home | Links | Contact Us | More About Intellectual Property | Bookmark

Search patents:

Home

Electrical and Wave

Circuit-for-measuring-discharging-and-charging-current-of-a-battery-providing-offset-drift-voltage-for-correcting-amplifier-output

Battery check device

In order to eliminate the shortcomings of the conventional device, an object of the present ...

Low-drop voltage regulator

It is an object of the present invention to provide a highly reliable, long-life voltage regulator ...

Automatic pressure control system

What is claimed is: 1. A pressure supply system for supplying adjustable and controlled outlet ...

Drive system for household appliances

Among the several objects of the present invention may be noted the provision of a control system ...

Apparatus for controlling electrical power consumption

We claim: 1. Apparatus for controlling electrical power consumption by a load of a consumer drawing ...

Load current sharing circuit

OF THE INVENTION The load sharing circuit of the invention provides load current sharing among ...

Processing unit and system including plurality of the processing units

An object of the present invention is to avoid an overload of a power source if the sum of the ...

Boost-input backed-up uninterrupted power supply

A first object of the invention backed-up power supply is to use an input rectifier and filter ...

Uninterruptible power supply with improved output regulation

Although this invention is susceptible to embodiments of many different forms, a preferred ...

Power shedding device

Among the various objects and features of the present invention may be noted the provision of an ...

Circuit for measuring discharging and charging current of a battery providing offset/drift voltage for correcting amplifier output

Details

Inventors: Goto, Seiji; Tsunoda, Kazuaki; Murayama, Yukio;
Assignee: Fujitsu Limited (Kawasaki, JP)
Primary Examiner: Strecker; Gerard R.
Assistant Examiner: Do; Diep
Attorney, Agent or Firm: Staas & Halsey

A current measuring circuit for measuring discharging current and charging current of a battery, which is selectively connected to a load and a charger. The current measuring circuit comprises a resistor connected in series with the battery having a sufficiently low resistance value as not to substantially restrain the output current from the battery and a differential amplifier for amplifying a potential difference between both ends of the resistor. By providing a switch for short-circuiting one input terminal and the other input terminal of the differential amplifier, an offset/drift voltage of the differential amplifier can be obtained. This offset/drift voltage is used for correcting the output voltage from the differential amplifier at the time of current measurement and, thereby, the discharging current and charging current of the battery can be measured accurately.

DETAILED DESCRIPTION Accordingly, an object of the present invention is to provide a current measuring circuit capable of measuring battery discharging current and charging current over a wide range from a small current to a large current.
Another object of the present invention is to provide a current measuring circuit capable of correctly measuring the battery discharging current and charging current with an economical structure, which does not require the use of expensive parts.
In accordance with an aspect of the present invention, there is provided a current measuring circuit for measuring discharging current and charging current of a battery comprising a first battery, which is selectively connected to a load and a charger; a resistor connected in series with the first battery and having a sufficiently low resistance value as not to substantially restrain the output current from the first battery; and a first differential amplifier for amplifying a potential difference across the resistor, the first differential amplifier comprising a first operational amplifier, a first resistor connected between one end of the resistor and one input terminal of the first operational amplifier, a second resistor connected between the one input terminal and the output terminal of the first operational amplifier, a third resistor connected between the other end of the resistor and the other input terminal of the first operational amplifier, and a fourth resistor connected between the other input terminal of the first operational amplifier and ground, wherein the resistance value of the first resistor is set equal to the resistance value of the third resistor and the resistance value of the second resistor is set equal to the resistance value of the fourth resistor.
Preferably, the current measuring circuit is provided with a short-circuiting means for short-circuiting the one input terminal and the other input terminal of the first operational amplifier, so that the output voltage of the first operational amplifier in such short-circuited state, i

Related patents

	In-circuit current measurement The present invention provides a method for the accurate and reliable measurement of currents in a circuit without breaking the circuit to insert a measuring device. The ...
	Live circuit resistance measurement system and method The problems discussed above are solved in the present invention which is a system that measures the resistance of a portion (e.g., a power bus connection) of a live ...
	Circuit arrangement and method for pulsated charging of batteries What is claimed is: 1. Circuit arrangement for pulsated charging of batteries, comprising: an alternating current source having a predetermined inductance and a pair of ...
	Method and apparatus for controlling the input impedance of a power converter This invention teaches that the control of a DC-DC converter can be implemented using energy control, knowing the power of the input, the output and the losses, and ...
	Electronic photoflash The present invention relates to an electronic photoflash system having features to avoid wasteful consumption of energy stored in a battery power supply when, for ...
	Power supply apparatus for efficient power conservation of a battery It is therefore an object of the present invention to provide a power supply apparatus which is capable of using an alkaline cell, manganese cell or the like and ...
	Secondary battery boost circuit The present invention provides for a boost circuit which engages a secondary "bridge" or back-up power supply upon an output of a primary power supply falling below ...
	Power supply apparatus having a function of compensating for changes in voltage A description will now be made of constructions of the present invention, for achieving the above objects. They will be described by affixing reference numerals employed ...
	Rechargeable device with operational inhibit during recharging The present invention provides a device having an electrical load supplied with power from a rechargeable secondary battery and adapted to mate with a charger that ...
	Shielded computer network switch The present invention utilizes absorption methodology and unique grounding techniques to substantially enhance computer network security . A cost effective non-woven ...

0.014
Archive: All patents - Links Copyright (c)2006 Eipa-patents.org - All rights reserved