Electricity: battery or capacitor charging or discharging – Battery or cell charging – Plural charging sources
Reexamination Certificate
2000-01-27
2001-10-09
Wong, Peter S. (Department: 2838)
Electricity: battery or capacitor charging or discharging
Battery or cell charging
Plural charging sources
C307S066000
Reexamination Certificate
active
06300745
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method in charging a battery powered device and an apparatus for working said method.
2. Description of the Prior Art
If the battery in prior art battery powered devices having a built-in charge control circuit controlled by the device, and a switch for connecting the device including the battery to a battery charger, has been discharged to such extent that the voltage thereof is too low to feed the device and to activate the charge control circuit thereof in order to initiate normal charging of the battery over said circuit when the device is connected to the charger, it may be impossible to start the device even if it is connected to the charger, and thus to charge the battery.
When the battery powered device having an almost flat battery is switched on the behaviour of the device accordingly is upredictable. Will the device be switched on correctly? Will the extra current flow to the device caused by decoupling capacitors when the device is switched on lower the battery voltage even more?
Different alternatives are available in order to charge the battery in case the device is not able to initiate charging due to lack of enough power from the battery when the device including the battery is connected to the charger:
The battery is disconnected from the device and placed in a charger and then, when it has been charged, is replaced into the device. This must be done by the user himself, which makes the handling of the device more tedious;
The device including the battery is connected to a charger which supplies a small trickle charge current which independently of the charge control circuit always charges the battery when connected to the charger. Eventually, the battery voltage will reach a level which is high enough in order to operate the device and initiate normal charging of the battery over the charge control circuit. In this case if the trickle charge current is supplied by a simple trickle charge resistor the trickle charge current has to be very low to prevent damage of the battery should the battery be charged already when it is connected to the charger. It follows that charging of a flat battery to switch-on level will take long time;
The device is operated by the charging voltage which is applied directly to the device when the battery is connected to the charger. In this case the power supplied to the device cannot be controlled satisfactorily as to the quality thereof.
The charging voltage is transformed to a high quality voltage used for operating the device when the battery is connected to the charger. This solution necessitates extra components to be included into the charger.
BRIEF SUMMARY OF THE INVENTION
In order to overcome the drawbacks mentioned above and to make the behaviour of the device predictable without any risk of damaging the battery by a too high uncontrollable trickle charge current, the invention provides a method in charging a battery powered device having a built-in charge control circuit controlled by the device, by connecting the device including the battery to a battery charger, wherein the device including the battery initially when the battery voltage is too low to initiate normal charging of the battery over the charge control circuit, is connected to the battery charger via a current generator which is switched off when the battery voltage has increased to a level which is high enough to support normal charging of the battery over the charge control circuit.
The invention also provides an apparatus for working the method comprising a battery powered device having a built-in charge control circuit controlled by the device, and a switch for connecting the device including the battery to a battery charger under the control of said charge control circuit for charging said battery, wherein a current generator is shunted over said switch to be switched on when the battery voltage is not high enough to initiate, over said charge control circuit, normal charging of the battery via said switch.
When the battery-powered device is connected to the charger and the battery voltage of the device is too low for normal operation, the current generator charges the battery with a well defined safe charge current independently of the normal charging circuit controlled by the device. The current generator will be switched off at a predetermined battery voltage which may be chosen such that a secure start-up of the device is guaranteed. When the predetermined voltage has been reached the device will be switched on in normal way and start recharging of the battery over the charge control circuit. The charge current supplied by the current generator does not have to be low since it is switched off when the battery voltage has reached the predetermined value. Thus, there is no risk of damage to the battery due to a too high uncontrollable charge current being supplied to the battery by the current generator, and a flat battery is charged rapidly. The behaviour of the device is predictable. The invention allows use of a normal battery. The current generator circuit is built into the apparatus and will not be noticed by the user, no external components being needed.
REFERENCES:
patent: 5568039 (1996-10-01), Fernandez
patent: 5569550 (1996-10-01), Garrett et al.
patent: 5691622 (1997-11-01), Mack et al.
patent: 5898294 (1999-04-01), Gold
patent: 0 865 141 A2 (1998-09-01), None
patent: 96/24170 (1996-08-01), None
Klingström Leif
Olsson Torbjorn
Nixon & Vanderhye PC
Telefonaktiebolaget LM Ericsson
Tibbits Pia
Wong Peter S.
LandOfFree
Method in charging a battery powered device and apparatus... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method in charging a battery powered device and apparatus..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method in charging a battery powered device and apparatus... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2599992