U.S. patent application number 09/841616 was filed with the patent office on 2002-11-07 for common pin voltage regulator.
Invention is credited to Harmon, Jack Douglas.
Application Number | 20020163321 09/841616 |
Document ID | / |
Family ID | 25285310 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020163321 |
Kind Code |
A1 |
Harmon, Jack Douglas |
November 7, 2002 |
COMMON PIN VOLTAGE REGULATOR
Abstract
A voltage regulator having a single I/F terminal is disclosed.
According to the teachings of the present invention, the I/F
terminal of the present invention precludes the use of an I
terminal alternator model and a separate F terminal model. The I/F
terminal provides the function of both the I and F terminal which
were heretofore provided in separate voltage regulator models.
Inventors: |
Harmon, Jack Douglas;
(Carmel, IN) |
Correspondence
Address: |
MARGARET A. DOBROWITSKY
DELPHI TECHNOLOGIES, INC.
Legal Staff, Mail Code: 480-414-420
P.O. Box 5052
Troy
MI
48007-5052
US
|
Family ID: |
25285310 |
Appl. No.: |
09/841616 |
Filed: |
May 2, 2001 |
Current U.S.
Class: |
322/28 |
Current CPC
Class: |
H02J 7/24 20130101 |
Class at
Publication: |
322/28 |
International
Class: |
H02P 009/00; H02H
007/06; H02P 011/00 |
Claims
What is claimed is:
1. A voltage regulator for an automotive alternator battery
charging system, said automotive alternator battery charging system
further comprising a battery and an alternator coupled to the
battery, and an operator-controlled switch connected between the
battery and said voltage regulator for activating said voltage
regulator upon closure of the operator-controlled switch, wherein
the alternator is further drivingly coupled to a vehicle engine and
provides a rectified output charging signal for charging the
battery in accordance with an excitation signal provided by said
voltage regulator to a field coil of the alternator, said voltage
regulator comprising: a first module responsive to the battery
voltage for providing a sensed signal representative of the battery
voltage; a field terminal; a second module for providing an
excitation signal to the alternator field coil in response to said
sensed signal, wherein said excitation signal is provided at said
field terminal; an input terminal; an I/F terminal connected via a
unidirectional switch to said input terminal and further connected
to said field terminal; and wherein said I/F terminal provides a
signal representative of the excitation signal when said
unidirectional switch is open and provides a bypass circuit around
said input terminal when said unidirectional switch is closed.
2. The voltage regulator of claim 1 wherein the unidirectional
switch comprises a series connection of a diode and a resistor.
3. The voltage regulator of claim 1 wherein the I/F terminal is
connected to the field terminal via a resistor.
4. The voltage regulator of claim 1 wherein the input terminal goes
to a low voltage state when the alternator stops rotating.
5. The voltage regulator of claim 1 further comprising a turn-on
circuit responsive to the rotation of the alternator, wherein said
turn-on circuit provides a signal to the L terminal when there is
no field excitation.
6. The voltage regulator of claim 5 wherein the turn-on circuit
connects the input terminal to ground when there is no field
excitation.
7. The voltage regulator of claim 5, wherein the turn-on circuit
includes a controller responsive to the excitation signal for
switching a transistor, wherein when said transistor is switched
on, a circuit is completed to ground via the collector-emitter
junction of said transistor, thereby placing the input terminal at
ground potential.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to an automotive alternator
system, and more specifically to a voltage regulator for such a
system that advantageously reduces the number of external
connections between the voltage regulator and the various
automotive systems.
[0002] Voltage regulator controlled automotive recharging systems
are commonly used to keep an automotive storage battery at full
charge and to provide sufficient electrical power for the operation
of the various automotive electrical accessories. Conventionally,
an alternator provides a rectified output current as it is driven
by a belt and pulley arrangement coupled to the automobile internal
combustion engine. The alternator comprises a field winding, a
3-phase stator winding, and a full-wave diode rectifier for
converting the poly-phase AC output of the windings to a DC
voltage. The alternator operation is controlled through a closed
feedback system by the voltage regulator, which senses the battery
voltage and controls the alternator field coil excitation in
response thereto attempts to maintain a full charge on the battery.
An indicator lamp typically provides an indication to the
automobile operator of the absence of an alternator output voltage
and in this way alerts the operator to a malfunction in the
electrical system.
[0003] In some charging systems, a continuous DC field coil
excitation current is provided. Alternatively, switching-based
voltage regulators operate in an on/off mode wherein a switching
device is utilized to alternately stepwise excite the alternator
field coil between full and zero excitation values. In this system,
the rate of the stepwise excitation and the duration of the
excitation periods are varied in accordance with engine speed and
the resistive load placed upon the battery. Generally, the
alternator is defined as that device producing a polyphase output
current. When an alternator is coupled with a voltage regulator,
the device is referred to as a generator, which supplies a DC
current for charging the automobile battery.
[0004] In today's automobile market, the alternator and the
attendant voltage regulator are usually supplied by an automotive
parts vendor to the automobile manufacturers. There are many
different automobile types and also many different
electrical/charging systems among those automobile types. Although
there is some commonality between electrical/charging systems
employed in each automobile, many also have unique requirements in
the interface between the automobile engine control systems and the
alternator and voltage regulator. As a result, alternator/voltage
regulator vendors are required to supply several unique products to
interface with the wide variety of automobile control systems.
Designing, manufacturing and assuring that sufficient inventory
exists for each of the many alternator/regulator models results in
unnecessary expense for the alternator vendor, which is generally
passed through to the automobile manufacturer and then to the
automobile purchaser.
BRIEF SUMMARY OF THE INVENTION
[0005] The present invention overcomes the disadvantages associated
with the supply of several different generator (or
alternator/voltage regulator combination) models. In particular, by
interconnecting certain voltage regulator terminals according to
the teachings of the present invention, a single generator model
can be employed in several different automobile systems. In the
prior art, several different generator systems are required,
dependent on the interface requirements of the electrical charging
system of the automobile.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present invention can be more easily understood and the
further advantages and uses thereof more readily apparent, when
considered in view of the description of the preferred embodiments
below and the following figures in which:
[0007] FIGS. 1 and 2 are combination block diagrams and electrical
schematic diagrams of prior art alternator, voltage regulator and
battery systems; and
[0008] FIGS. 3 and 4 are combination block diagrams and electrical
schematic diagrams illustrating an alternator, voltage regulator
and battery system according to the teachings of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] Before describing in detail the particular apparatus in
accordance with the present invention, it should be observed that
the present invention resides primarily in a novel combination of
hardware related to a voltage regulator for an automobile
alternator. Accordingly, the hardware components have been
represented by conventional elements in the drawings, showing only
those specific details that are pertinent to the present invention
so as not to obscure the disclosure with structural details that
will be readily apparent to those skilled in the art having the
benefit of the description herein.
[0010] FIG. 1 illustrates a portion of a prior art automotive
electrical system to which the teachings of the present invention
can be applied. The battery charging system of FIG. 1 comprises an
alternator 5, a battery 6, an ignition switch 7, a charge
indicating lamp 8 and a voltage regulator 15.
[0011] The alternator 5 comprises a rotatable field coil winding 20
that is drivingly coupled to the crank shaft of the automobile
engine. The alternator 5 further comprises three stationary
alternator output windings 21, 22 and 23, which are connected in a
delta configuration between three terminals 24, 25 and 26 as shown.
It is understood by those skilled in the art that the windings 21,
22 and 23 can also be configured in a wye winding configuration.
Each of the terminals 24, 25 and 26 is coupled to a respective
anode terminal of a rectifying diode 27, 28 and 29. The cathode
terminals of the diodes 27, 28 and 29 are connected to a positive
rectified output terminal 19. Each of the terminals 24, 25 and 26
is also connected to the cathode terminal of diodes 34, 35 and 36,
the anode terminals of which are connected to ground.
[0012] All of the components 20 through 36 are typically considered
part of the alternator 5 and reside either within the alternator
within the alternator housing. In operation, the alternator 5
receives field coil excitation from a field+terminal of the voltage
regulator 15. In response to the excitation applied to the field
coil 20 and its rotation by the automobile engine, the alternator
windings 21, 22 and 23, operating in conjunction with the various
diodes 27, 28, 29, 34, 35, and 36, provide a rectified battery
charging output signal between the positive rectified output
terminal 19 and ground. This output signal is utilized to charge
the battery 6 and maintain a predetermined charge level
corresponding to a preset battery voltage magnitude. The structure
and operation of the alternator 5 is well known to those skilled in
the art and therefore will not be discussed further herein.
[0013] The ignition switch 7 is serially connected between a
terminal 9 of the charge indicating lamp 8 and the positive
terminal of the battery 6. A second terminal of the charge
indicating lamp 8 is connected to a lamp terminal of the voltage
regulator 15. When the ignition switch 7 is closed, current flows
from the battery 6 through the charge indicating lamp 8 to a lamp
driver circuit 10 within the regulator control circuits 42. The
voltage on the lamp terminal turns on the regulator 15. Also, when
the switch 7 is closed, a starter motor 56 is energized by the
battery 6 for starting the automobile engine. In lieu of the
physical switch 7 shown in FIG. 1, a pull-up switch in the vehicle
computer controller can be used. The switch 7 remains closed during
operation of the vehicle; the pull-up switch may be switched off at
certain times to reduce the load on the engine.
[0014] The lamp driver 10 comprises a turn-on circuit 12, for
driving a transistor 13 via the base terminal thereof. The lamp
terminal is further connected to ground via the collector-emitter
junction of the transistor 13 and a series resistor 14. Immediately
after the switch 7 is closed, the turn-on circuit 12 senses
rotation of the alternator 5 (via circuitry within the regulator
control circuits 42, not shown in FIG. 1) and in response turns the
transistor 13 off, thus opening the circuit between the lamp 8 and
ground, thereby extinguishing the lamp 8. The driver circuit 10 is
further responsive to rotation of the alternator for turning the
lamp 8 on when there is no rotation. The lamp is illuminated when
the turn-on circuit 12 turns the transistor 13 on, so that the lamp
8 is connected between the battery 8 and ground via the
collector-emitter junction of the transistor 13 and the series
resistor 14. The turn-on circuit 12 is also responsive to certain
voltage faults (not germane to the present invention) for
illuminating the lamp 8.
[0015] Further, in response to the closure of the switch 7 to start
the vehicle, the regulator control circuits 42 bias the gate
terminal of an MOSFET 46 via a resistor 43. The drain terminal of
the MOSFET 46 provides the field excitation current to the field
coil winding 20 via a field+terminal (also referred to as the
F+terminal). Conventionally, the field excitation current is a
pulse-width modulated signal. A suppression diode 48 is connected
between the drain terminal of the MOSFET 46 and ground as shown.
Also, when the ignition switch 7 is closed, a power supply circuit
within the regulator 15 is activated for supplying DC power for the
various components of the regulator control circuits 42. As is well
known by those skilled in the art, the ignition switch 7
corresponds to the automobile ignition switch. The function and
operation of the switch 7 and the charge indicating lamp 8 are well
known to those of average skill in the art.
[0016] The P or phase input terminal of the voltage regulator 15 is
connected to the cathode terminal of the diode 34. This connection
provides a phase angle signal to the voltage regulator control
circuits 42 to determine the rotational speed of the alternator 5.
A voltage divider comprising resistors 50 and 72 is interposed
between the phase input terminal and the regulator control circuits
15 to properly adjust the magnitude of the phase angle signal. In
the event either of the diodes 34 or 27 fails (either opens or
shorts) the phase signal is lost and in response the voltage
regulator 15 illuminates the charge indicating lamp 8 via the
turn-on circuit 12. In the event the switch 7 is opened, to shut
off the engine for example, but the engine continues to run, as
determined by the continued presence of a signal on the phase input
terminal, the alternator 5 continues to charge the battery 6, but
at a lower voltage level.
[0017] In certain automobile installations, a voltage sensing
terminal, referred to as an S terminal or sense terminal, of the
voltage regulator 15 is coupled to a terminal 54 of the starter
motor 56. As discussed above, when the switch 7 is closed, the
starter motor 56 is energized by the battery 6 for starting the
automobile engine. The voltage sensing terminal 52 provides a
signal representative of the battery voltage to the regulator
control circuits 42, via a voltage divider comprising the resistors
74 and 76. In response to this sensed battery voltage, the voltage
regulator 15 provides field coil excitation to the field coil 20,
resulting in the alternator 5 providing a rectified alternator
output charging signal between the terminal 19 and ground. In this
way, the battery charging system forms a closed loop feedback
system wherein the alternator 5 maintains the voltage across the
battery 6 at a preset magnitude, thereby maintaining the battery 6
in a charged condition.
[0018] In other automobile installations an internal voltage sense
is utilized in lieu of the external sense provided at the sense
terminal of the voltage regulator 15. The internal sense is
provided by the terminal GO, which is discussed further
hereinbelow, of the regulator 15. The external sense technique is
typically used where the battery 6 is located a significant
distance from the alternator 5, due to the series resistance and
the voltage drop created thereby in the wire connecting the
alternator 5 and the battery 6.
[0019] The terminal 54 is also connected to the battery 6 and
vehicle loads, illustrated in the aggregate as vehicle loads 57,
for supplying energy to those loads during operation of the
vehicle.
[0020] The GO terminal of the regulator 15 is connected to the
terminal 17 of the alternator 5. A DC voltage is provided to the
terminal GO from the battery 6, for supplying operating voltage to
the regulator control circuits 42. A filter comprising a resistor
60 and a capacitor 62 is interposed between the GO terminal and the
voltage regulator circuits 42. A first terminal of the resistor 60
is connected to the GO terminal and the second terminal thereof is
connected to the regulator control circuits 42. The second terminal
of the resistor 60 is also connected to ground via a capacitor 62.
Thus, the resistor 60 and the capacitor 62 function as a voltage
divider and filter for the DC voltage present at the terminal
GO.
[0021] In the embodiment of the voltage regulator 15 illustrated in
FIG. 1, an I terminal of the voltage regulator 15 is connected to
the terminal 9 between the charge indicating lamp 8 and the switch
7. Internal to the voltage regulator 15, the I terminal is
connected to the lamp terminal via a resistor 78 as shown. The I
terminal serves as a redundant terminal for conveying switch 7
closure status to the regulator control circuits 42 when the lamp
has burned out, i.e., opened.
[0022] FIG. 2 illustrates an embodiment of a voltage regulator 17
similar to the voltage regulator 15 of FIG. 1; excluding the I
terminal from FIG. 1, but including an F terminal connected to the
field+terminal via a resistor 80, as shown, and further connected
to an automotive control system 82. The automotive control system
82 senses the voltage at the F terminal to determine whether and
how much field excitation current is being supplied to the rotating
field coil 20. This voltage determines whether an idle boost is
appropriate when the loads 57 are requiring additional current.
That is, the F terminal signal is representative of the field
excitation current and if that current is at its maximum value,
then the automotive control system 82 increases the engine idle
speed so that more current is supplied by the alternator 5 to the
vehicle loads 57. In the so-called F-terminal model, i.e., the
voltage regulator 17, as shown in FIG. 2, the switch 7 is connected
to the automotive control system 82 to sense switch closure.
Closure of the switch 7 provides power to the automotive control
system 82 and activates the voltage regulator 17. The lamp 8 is not
present in the FIG. 2 embodiment, and thus the lamp terminal is
referred to as the L terminal. The control system 82 monitors the
F-terminal and L-terminal voltages for illuminating a trouble
signal on the vehicle dashboard (not shown in FIG. 2).
[0023] In summary, the prior art includes two different voltage
regulator models; the voltage regulator 15 illustrated in FIG. 1
and a the voltage regulator 17 illustrated in FIG. 2. The FIG. 1
embodiment includes an I terminal while the FIG. 2 embodiment
includes an F terminal. The automobile manufacturer chooses either
the I terminal model or the F terminal model dependent upon the
specific engine control systems designed into the automobile.
[0024] Advantageously, according to the teachings of the present
invention a voltage regulator 18 is provided wherein a single
terminal, referred to as the I/F terminal, replaces both the I
terminal model of FIG. 1 and the F terminal model of FIG. 2. As
shown in FIG. 3, the voltage regulator 18 (I/F terminal model)
includes the resistor 80 connected to the field+terminal as shown
in FIG. 2, and further including a connection between the I/F
terminal and the lamp terminal via the series combination of a
resistor 102 and a diode 104. The anode terminal of the diode 104
is connected to the resistor 102 and the cathode terminal thereof
is connected to the lamp terminal.
[0025] When installed in an automobile, the I/F terminal of the
voltage regulator 18 can be connected to the automotive control
system 80 (as shown in FIG. 3) or to the switch side of the lamp 8
(as shown in FIG. 4). Thus, the present invention provides for the
supply of a single regulator model for both automotive
installations.
[0026] In the FIG. 3 installation, when the alternator 5 is
operating properly, the lamp terminal is driven high by the lamp
driver 10, as discussed in conjunction with FIG. 1. The lamp 8 is
not used in the FIG. 3 embodiment. This high voltage reverse biases
the diode 104, effectively opening the circuit between the I/F
terminal and the lamp terminal. As a result, the I/F terminal
functions as a conventional F terminal, connected to the
field+terminal by the resistor 80 and to the automotive control
system 82, as discussed in conjunction with FIG. 2.
[0027] The voltage regulator 18 according to the teachings of the
present invention can also be installed in a vehicle as shown in
FIG. 4. In this installation the I/F terminal is connected between
the switch 7 and the lamp 8, creating a bypass circuit around the
lamp 8 when burned out (i.e., open circuited). Note that this
bypass circuit serves the same function as the I terminal in FIG.
1. The voltage at the point between the switch 7 and the lamp 8
forward biases the diode 104 and turns the regulator 18 on when the
lamp is open.
[0028] Thus, as can now be appreciated, the present invention (the
voltage regulator 18) provides for supplying a single voltage
regulator model that can provide the functions of two prior art
voltage regulator models (voltage regulators 15 and 17). While the
invention has been described with reference to a preferred
embodiment, it will be understood by those skilled in the art that
various changes may be made and equivalent elements may be
substituted for elements thereof without departing from the scope
of the invention. The scope of the present invention further
includes any combination of the elements from the various
embodiments set forth herein. In addition, modifications may be
made to adapt a particular situation to the teachings of the
present invention without departing from the essential scope
thereof. Therefore, it is intended that the invention not be
limited to the particular embodiment disclosed as the best mode
contemplated for carrying out this invention but that the invention
will include all embodiments falling within the scope of the
appended claims.
* * * * *