U.S. patent application number 09/924284 was filed with the patent office on 2002-03-07 for system for automatically charging the battery of a remote transmitter for use in a vehicle security system.
This patent application is currently assigned to Lear Corporation. Invention is credited to Campbell, Douglas C., Ghabra, Riad, King, Ronald O., Nantz, John S., Tang, Qingfeng.
Application Number | 20020027424 09/924284 |
Document ID | / |
Family ID | 24263504 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020027424 |
Kind Code |
A1 |
Nantz, John S. ; et
al. |
March 7, 2002 |
System for automatically charging the battery of a remote
transmitter for use in a vehicle security system
Abstract
A system for automatically charging a battery of a remote
keyless entry transmitter includes a voltage monitoring circuit
having a first microprocessor which monitors battery voltage and
which causes the transmitter to send an RF signal to a receiver in
the form of a base station on a motor vehicle. The signal causes a
charging circuit of the base station to activate an inductive field
to cause the battery to be fully charged. In one embodiment, the
first microprocessor also causes the transmitter to send a second
signal to the base station to shut down the charging field when the
battery voltage reaches a predetermined upper limit. In another
embodiment, a second microprocessor of the base station tracks the
charging time and shuts down the charging field when the charging
time reaches a predetermined amount. Alternatively, charging can be
done by direct contact or other means. In this way, the system not
only allows for extended battery life by limiting the number of
charge cycles on the battery but also allows for optimum discharge
of the battery before a charging cycle begins.
Inventors: |
Nantz, John S.; (Brighton,
MI) ; Ghabra, Riad; (Dearborn Heights, MI) ;
Tang, Qingfeng; (Novi, MI) ; King, Ronald O.;
(Brownstown, MI) ; Campbell, Douglas C.;
(Northville, MI) |
Correspondence
Address: |
David R. Syrowik
Brooks & Kushman P.C.
22nd Floor
1000 Town Center
Southfield
MI
48075-1351
US
|
Assignee: |
Lear Corporation
Southfield
MI
|
Family ID: |
24263504 |
Appl. No.: |
09/924284 |
Filed: |
August 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09924284 |
Aug 8, 2001 |
|
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|
09566585 |
May 8, 2000 |
|
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|
6291968 |
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Current U.S.
Class: |
320/108 |
Current CPC
Class: |
H02J 7/00302 20200101;
H02J 7/342 20200101; H02J 50/80 20160201; H02J 7/02 20130101; H02J
50/12 20160201 |
Class at
Publication: |
320/108 |
International
Class: |
H02J 007/00 |
Claims
What is claimed is:
1. A charging system for automatically charging a battery of a
remote transmitter for use in a vehicle security system having a
base station, the charging system comprising: a voltage monitoring
circuit for monitoring voltage of the battery and causing the
transmitter to transmit a first signal when the voltage drops below
a predetermined lower limit; a charging circuit for charging the
battery during a charging cycle in response to the first signal
when the battery is coupled to the charging circuit for charging;
and a determining circuit for determining when the battery is fully
charged and providing a corresponding fully charged signal wherein
the charging circuit stops charging the battery in response to the
fully charged signal.
2. The charging system as claimed in claim 1 wherein the charging
circuit is inductively coupled to the battery during charging.
3. The charging system as claimed in claim 1 wherein the voltage
monitoring circuit includes a first microprocessor programmed to
monitor the voltage of the battery.
4. The charging system as claimed in claim 1 wherein the
determining circuit includes a charging time monitoring circuit for
monitoring the amount of time the battery is coupled to the
charging circuit and is being charged thereby and providing the
fully charged signal when the time reaches a predetermined
amount.
5. The charging system as claimed in claim 4 wherein the charging
time monitoring circuit includes a second microprocessor programmed
to monitor the amount of time that the charging circuit charge s
the battery to ensure that the battery is fully charged before the
charging cycle is complete.
6. The charging system as claimed in claim 1 wherein the first
signal is an RF signal.
7. The charging system as claimed in claim 3 wherein the first
microprocessor is further programmed to cause the transmitter to
transmit the fully charged signal when the battery is fully
charged.
8. The charging system as claimed in claim 7 wherein the fully
charged signal is an RF signal.
Description
TECHNICAL FIELD
[0001] The present invention relates to systems for automatically
charging the battery of a remote transmitter which is used in a
vehicle security system.
BACKGROUND ART
[0002] Rechargeable batteries used in remote transmitters of
vehicle security systems currently have typically 1000
charge/discharge cycles before "end of life." Current methodologies
allow for a certain level of discharge before the charging cycle
begins. However, if the battery is removed from its charging
fixture or field before it is fully charged, charging will not
commence until that battery voltage drops below a voltage
threshold.
[0003] U.S. Pat. No. 6,023,151 discloses a "smart" battery method
and apparatus including a dynamic end of voltage (EODV) signal for
recharging batteries, one that reflects environment, temperature,
chemistry, or cycle and provides enhanced runtime and save-to-disk
alarm.
[0004] U.S. Pat. No. 6,016,047 discloses a battery management
system suitable for a "smart" battery including a processor and
other means for recovery and producing signals based on
temperature, and chemistry status.
[0005] U.S. Pat. No. 6,011,546 discloses a "smart" battery, part of
a larger system, including provisions for self-monitoring and
signals mobile processor battery charge state, readiness for re-use
following charging, and modules user interface.
[0006] U.S. Pat. No. 5,870,685 discloses a system for monitoring
battery capacity in a mobile station including a plurality of
different thresholds which may trigger transmission of a signal for
shutdown and recharging.
[0007] U.S. Pat. No. 5,754,029 discloses a battery charging
apparatus including means for controlling battery charging current
via calendars stored in PROM and uses specified event dates as well
as a microprocessor for sending messages to an RF modulator.
[0008] U.S. Pat. No. 5,606,240 discloses a battery charger for a
lithium battery including means for lengthening or shortening
battery charging time based on a plurality of thresholds including
protection, status, charge and time.
[0009] U.S. Pat. No. 5,572,110 discloses a "smart" battery charger
including a memory for thresholds and parameters, means for
automatically controlling the charging operation, and means for
optimizing charging based on temperature, time, battery
characteristics and requirements.
[0010] U.S. Pat. No. 5,847,546 discloses a "smart" battery charging
system including a memory and a microprocessor for programming
charges and means for generating a charging signal that responds to
charging status of the battery being charged.
[0011] U.S. Pat. No. 5,850,188 discloses an RKE diagnostic system
including means for transmitting a plurality of signals regarding
operations including charge status of battery and battery
condition.
[0012] U.S. Pat. No. 5,717,387 discloses a vehicle control system
including the ability to reprogram vehicle operation via
transmitting signals such as low battery capable of controlling
vehicle accessories.
[0013] U.S. Pat. No. 4,395,672 discloses an improved timer for a
battery charger including an electric controller and includes a
plurality of thresholds and parameters that extend charging cycle
and to operate automatically.
[0014] Inductive (i.e. magnetic) coupling is a means of
transferring electrical energy from one part (area) of a circuit to
another part without requiring any ohmic (wire) connection.
Instead, magnetic flux linkages couple two inductors (coils). The
coils must be in close proximity in order to establish sufficient
mutual inductance.
DISCLOSURE OF INVENTION
[0015] An object of the present invention is to provide a system
for automatically charging the battery of a remote transmitter for
use in a vehicle security system wherein charging/discharging of
the battery is performed in such a way to fully utilize maximum,
battery-life potential.
[0016] Another object of the present invention is to provide a
system for automatically charging the battery of a remote
transmitter for use in a vehicle security system wherein a
predetermined level of discharge is achieved before a charging
cycle begins and wherein a full charge cycle is completed before
the charging cycle is complete.
[0017] Yet still another object of the present invention is to
provide a system for automatically charging the battery of a remote
transmitter for use in a vehicle security system wherein a
determining circuit determines when the battery is fully charged.
In one embodiment, a microprocessor of the system monitors or
tracks charging time to ensure full charge before the charging
cycle is complete, even if the battery is removed from the charging
field/charging fixture for a period of time and the later placed
back in the field/fixture with a voltage above a predetermined
lower voltage limit.
[0018] In carrying out the above objects and other objects of the
present invention, a charging system for automatically charging a
battery of a remote transmitter for use in a vehicle security
system having a base station is provided. The charging system
includes a voltage monitoring circuit for monitoring voltage of the
battery and causing the transmitter to transmit a first signal when
the voltage drops below a predetermined lower limit. A charging
circuit charges the battery during a charging cycle in response to
the first signal when the battery is coupled to the charging
circuit for charging. A determining circuit determines when the
battery is fully charged and provides a corresponding fully charged
signal wherein the charging circuit stops charging the battery in
response to the fully charged signal.
[0019] The charging circuit may be inductively coupled to the
battery during charging.
[0020] The voltage monitoring circuit includes a first
microprocessor programmed to monitor the voltage of the
battery.
[0021] The determining circuit may include a charging time
monitoring circuit for monitoring the amount of time the battery is
coupled to the charging circuit and is being charged thereby and
providing the fully charged signal when the time reaches a
predetermined amount.
[0022] The charging time monitoring circuit may include a second
microprocessor programmed to monitor the amount of time that the
charging circuit charges the battery to ensure that the battery is
fully charged before the charging cycle is complete.
[0023] The first signal may be an RF signal.
[0024] The first microprocessor may further be programmed to cause
the transmitter to transmit the fully charged signal when the
battery is fully charged.
[0025] The fully charged signal may be an RF signal.
[0026] The above objects and other objects, features, and
advantages of the present invention are readily apparent from the
following detailed description of the best mode for carrying out
the invention when taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is a diagrammatic view of a vehicle security system
in which a charging system of the present invention operates;
and
[0028] FIG. 2 is a schematic circuit diagram of the charging system
of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0029] FIG. 1 diagrammatically illustrates a vehicle security
system, generally indicated at 20. A transmitter, generally
indicated at 22, is shown as a key fob having a plastic housing 24
that is conveniently sized to be carried in a purse or pocket, for
example. A plurality of pushbutton switches 26, 27, 28 and 30 are
selectively activated by a user to achieve a desired operation in
the vehicle security system. As illustrated, the key fob
conveniently serves as a key ring for holding one or more keys 32
in a conventional manner.
[0030] A receiver or base station 34 responds to the signals sent
from the transmitter 22. The base station 34 is supported on a
vehicle 36 and controls various security system functions in a
conventional manner.
[0031] In general, the charging system of the present invention
includes a charging circuit that is activated by an RF signal
transmitted by the transmitter 22 in response to a low voltage
threshold detected by a voltage monitoring circuit, but is
deactivated when the battery is fully charged such as once a
specified period of charging time has transpired instead of
monitoring a low voltage threshold. The system can also allow for
continuous charging until the battery reaches an upper level
threshold as also monitored by the voltage monitoring circuit. The
process is performed automatically without any user intervention.
The charging method can be performed using inductive coupling or
direct contact. Below is an example of how an inductively-coupled
charging system of the invention would function.
[0032] Referring to FIG. 2, the base station 34 includes a
conventional charging circuit including a series or parallel
connected capacitor 31 and inductor or coil 33. The charging
circuit generates a magnetic field preferably having a frequency of
about 125 KHz.
[0033] The charging circuit further includes a parallel or series
connected coil 35 and an inductor or coil 37 to complete the
transfer of electrical energy from the coil 33. A voltage regulator
39 of the charging circuit regulates the charging voltage applied
to a battery 42.
[0034] For normal RF use, a pair of clamping zenar diodes 41 and 43
clamp the inputs to an amplifier 45 of the transmitter 22. In turn,
the amplified output is applied to the LF transceiver portion of a
CPU/LF transceiver 40.
[0035] The battery-operated remote keyless entry (RKE) transmitter
22 is equipped with a voltage level detector 38 connected to the
CPU or microprocessor portion of the CPU/LF (low frequency)
transceiver 40 that monitors the voltage of the battery 42. The RKE
transmitter 22 is also typically equipped with an immobilizer
feature that allows for battery-less, inductive operation when
placed in the inductive or magnetic field generated by the base
station immobilizer located in the vehicle 36.
[0036] Once the battery voltage drops below a specified voltage,
the detector 38 provides a signal to the microprocessor of the
CPU/LF transceiver 40 which changes a bit in the pulses transmitted
by the transmitter 22 to let the base station 34, that works in
conjunction with the RKE transmitter 22, know that the battery
voltage is low. The charging circuit of the base station 34 located
in the vehicle 36 continues to activate the inductive field until
the RKE transmitter battery 42 is fully charged.
[0037] The methodology for determining when the battery is "fully
charged" utilizes either one or both of the following:
[0038] The detector 38 and the CPU/LF transceiver 40 of the
transmitter 22 monitor voltage until an upper voltage threshold is
achieved, then the transmitter 22 transmits a pulse to the base
station 34 indicating such.
[0039] The base station 34, once it receives a low voltage
indication, continues to charge that particular transmitter 22 for
a specified period of time before the charging field generated by
the charging circuit is shut down. A charging time monitoring
circuit including a second microprocessor of the base station 34
tracks the charging time together with an associated transmitter
ID, as multiple transmitters may be used with a single base station
34.
[0040] This process is performed to eliminate unnecessary charging
cycles and to fully charge the battery 42 between cycles instead of
only charging the battery 42 to a level slightly above the low
voltage threshold.
[0041] While the best mode for carrying out the invention has been
described in detail, those familiar with the art to which this
invention relates will recognize various alternative designs and
embodiments for practicing the invention as defined by the
following claims.
* * * * *