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Claims  |
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We claim:
1. A telephone activated power controller comprising:
a power input means for receiving electrical AC power;
a power output means connected to the power input means for supplying
electrical AC power to output devices;
a telephone input means for receiving signals generated by outside
telephonic systems;
a telephone output means for delivering telephonic signals to said output
devices;
a power control means connected intermediate the power input means and the
power output means for controlling the flow of power from the power input
means to the power output means and for disrupting said power flow
responsive to a power-on or power-off signal, the power control means
including a NAND gate for receiving the power-on and power-off signals and
for sending relay signals responsive to said power-on and power-off
signals, a relay connected intermediate the power input means and the
power output means for switching on and off power from the power input
means to the power output means, a transistor connected to said relay for
controlling said relay responsive to said relay signals, a resistor
connected intermediate said NAND gate and said transistor for providing
transistor isolation, a diode connected in parallel with said relay for
shunting stored magnetic energy when said relay is turned off, a resistor
connected intermediate the power supply means and said relay for
protecting said relay from overheating, and a capacitor connected
intermediate said relay and said NAND gate for delaying the reception of a
power-on signal at said NAND gate to prevent instability;
a detection means connected to the telephone input means, telephone output
means, and the power control means for detecting a ring signal from the
telephone input means or an off-hook condition from the telephone output
means and for delivering a power-on signal to the power control means
responsive to said ring signal or said off-hook condition and for
providing a connection between the telephone input means and the telephone
output means and for delivering a power-off signal to the power control
means responsive to an on-hook condition from the telephone output means;
and
a power supply means connected to the power input means for providing a
plurality of power levels.
2. A telephone activated power controller comprising:
a power input means for receiving electrical AC power;
a power output means connected to the power input means for supplying
electrical AC power to output devices;
a telephone input means for receiving signals generated by outside
telephonic systems;
a telephone output means for delivering telephonic signals to said output
devices;
a power control means connected intermediate the power input means and the
power output means for controlling the flow of power from the power input
means to the power output means and for disrupting said power flow
responsive to a power-on or power-off signal;
a detection means connected to the telephone input means, telephone output
means, and the power control means for detecting a ring signal from the
telephone input means or an off-hook condition from the telephone output
means and for delivering a power-on signal to the power control means
responsive to said ring signal or said off-hook condition and for
providing a connection between the telephone input means and the telephone
output means and for delivering a power-off signal to the power control
means responsive to an on-hook condition from the telephone output means;
and
a power supply means connected to the power input means for providing a
plurality of power levels;
a computer interface means for allowing signals to pass between a computer
and the device;
a remote control means connected to the computer interface means and the
power control means for sending a power-on or power-off signal to the
power control means responsive to a computer signal;
a sense power output means connected to the power input means for supplying
electrical AC power to other devices such as units of a computer system;
a power sensor means connected intermediate the power input means and the
sense output means for detecting the flow of power from the power input
means to the sense power output means and for delivering a turn-off signal
to the power control means responsive to the termination of said flow of
power, the power sensor means comprising an optical-insolator connected
intermediate the power input means and the sense power output means for
detecting the flow of power from the power input means to the sense power
output means and for delivering a responsive power-on signal to the power
control means, a limiting network comprised of a plurality of diodes
connected parallel to said optical-insolator and a resistor connected
intermediate said optical-isolator and said diodes, for limiting the
current flow to said optical-isolator, a diode connected in parallel with
said optical-insolator for limiting the voltage, a resistor connected
parallel to said optical-isolator for setting a minimum current threshold
for said optical-isolator, and a low pass filter connected intermediate
said optical-isolator andd the power control means for limiting narrow
transients.
3. The device of claim 2 further including,
a status sensor means connected to the power supply means, the computer
interface means, and the power sensor means for sensing a power-on signal
from the power sensor means and delivering a status signal to the computer
interface means; and
an inhibit means connected to the power supply means, the computer
interface means, and the detection means for receiving an inhibit signal
from the computer interface means and preventing the detection means from
sending a power-on signal to the power control means.
4. The device of claim 3 further including,
a surge protection means connected intermediate the power input means and
the power output means for limiting the amount of power flowing from the
power input means.
5. The device of claim 4 further including,
an indicator means connected to the power supply means, the power sensor
means, the detection means and the remote control means for providing the
user with a visual indication of whether the device is on or off and
whether the power output means were last turned on manually by the power
sensor means or remotely by the detection means or remote control means.
6. The device of claim 1 wherein the power control means further comprises,
a delayed power output means connected to the surge protection means for
supplying electrical AC power to other devices such as a computer,
a delay relay connected intermediate the power input means and said delayed
power output means for switching on and off power from the power input
means to the delay power output means;
a delay transistor connected to said delay relay for controlling said delay
relay responsive to said relay signals;
an inverting gate connected intermediate said NAND gate and said delay
transistor for receiving said relay signals and controlling said delay
transistor responsive to said relay signals;
a RC network connected intermediate said NAND gate and said inverting gate
for delaying the receipt of said relay power-on signal by said inverting
gate for a period of time; and
a diode connected in parallel to said RC network for allowing immediate
receipt of said relay power-off signal by said inverting gate.
7. The device of claim 1 wherein the power supply means comprises,
a transformer connected to the power input means for stepping down the
voltage;
a full-wave bridge rectifier connected to said transformer for rectifying
the output of said transformer;
a capacitor connected to the output of said full-wave bridge rectifier for
providing a first DC source;
a regulator connected to the output of said full-wave bridge rectifier for
providing a second DC source;
a capacitor connected to said transformer for charging on the negative
swing of said transformer; and
a half-wave rectifier connected to said capacitor for providing a third DC
source.
8. The device of claim 1 wherein the remote control means comprises,
a remote transistor connected intermediate the computer interface means and
the power control means for receiving a computer stay-on signal and
sending a responsive power-on signal;
a protective network comprised of a resistor connected intermediate the
computer interface and said remote transistor, a resistor connected in
parallel with said transistor, and a diode connected in parallel with said
remote transistor, for providing remote transistor protection; and
a hysteresis network connected to the computer interface means for
absorbing spurious signals from the computer interface means.
9. The device of claim 3 wherein the status sensor means comprises,
a status inverting gate connected intermediate the power sensor means and
the computer interface means for receiving a power-on signal from the
power sensor means;
a parallel transistor connected intermediate said status inverting gate and
the computer interface means for sending a status signal to the computer
interface means;
a serial transistor connected intermediate said status inverting gate and
the computer interface means for sending a status signal to the computer
interface means;
a resistor connected intermediate said status inverting gate and said
parallel transistor for providing voltage protection and isolation;
a resistor connected parallel with said parallel transistor to provide
voltage division;
a resistor connected intermediate said parallel transistor and the power
supply means to provide voltage pull-up;
a resistor connected intermediate said status inverting gate and said
serial transistor to provide isolation;
a resistor connected intermediate said serial transistor and ground to
provide voltage division;
a resistor connected intermediate said serial transistor and the computer
interface means to provide voltage protection; and
a resistor connected intermediate said parallel transistor and the power
supply means to provide voltage pull-down.
10. The device of claim 3 wherein the inhibit means comprises,
an inhibit transistor connected intermediate the computer interface means
and said optical-isolator of the detection means for sending an inhibit
signal to said optical-isolator responsive to a computer signal;
a resistor connected intermediate the power supply means and said inhibit
transistor for keeping said inhibit transistor on in the absence of said
computer signal;
a resistor connected intermediate the computer interface means and said
inhibit transistor to provide voltage protection;
a resistor connected intermediate the computer interface means and the
power supply means for providing voltage protection;
an inverting transistor connected intermediate the computer interface means
and said inhibit transistor for inverting the computer signal sent to said
inhibit transistor;
a jumper connected intermediate the computer interface means and said
inhibit transistor and said reverse transistor for directing the computer
signal to said inhibit transistor or to said inverting transistor;
a diode connected in parallel to said inverting transistor for shunting
large voltages; and
a resistor and diode network connected intermediate the computer interface
and said inverting transistor for providing voltage protection.
11. A telephone activated power controller comprising:
a power input means for receiving electrical AC power;
a power output means connected to the power input means for supplying
electrical AC power to output devices;
a telephone input means for receiving signals generated by outside
telephonic systems;
a telephone output means for delivering telephonic signals to said output
devices;
a power control means connected intermediate the power input means and the
power output means for controlling the flow of power from the power input
means to the power output means and for disrupting said power flow
responsive to a power-on or power-off signal;
a detection means connected to the telephone input means, telephone output
means, and the power control means for detecting a ring signal from the
telephone input means or an off-hook condition from the telephone output
means and for delivering a power-on signal to the power control means
responsive to said ring signal or said off-hook condition and for
providing a connection between the telephone input means and the telephone
output means and for delivering a power-off signal to the power control
means responsive to an on-hook condition from the telephone output means,
the detection means including an RC load network connected to the ring
line of the telephone input means for providing a ring load, a full-wave
bridge rectifier connected to said RC load network and the tip line of the
telephone input means for rectifying the ring signal and providing a
current path for an off-hook condition signal, an optical-isolator
connected across said full-wave bridge for receiving ring and off-hook
condition signals from said full-wave bridge and for sending responsive
power-on and power-off signals to the power control means, a low pass
filter connected intermediate said optical-isolator andd the power control
means for eliminating spurious signals, a limiting network comprised of a
plurality of diodes connected in parallel to said optical-isolator and a
resistor connected intermediate said optical-isolator and said diodes for
limiting the current flow to said optical-isolator, a lock-out delay RC
network connected to the power control means for receiving and delaying a
relay control signal when the power output means have been powered up, a
lock-out transistor connected to said lock-out relay for controlling said
lock-out relay, a lock-out inverting gate connected intermediate said
telephone delay RC network and said lock-out transistor for receiving said
power-up signal and controlling said lock-out transistor responsive to
said power up signal, and a diode connected in parallel to said telephone
delay RC network for allowing immediate receipt of a relay control signal
by said lock-out inverting gate; and
a power supply means connected to the power input means for providing a
plurality of power levels.
12. The device of claim 11 wherein the power supply means comprises,
a transformer connected to the power input means for stepping down the
voltage;
a full-wave bridge rectifier connected to said transformer for rectifying
the output of said transformer;
a capacitor connected to the output of said full-wave bridge rectifier for
providing a first DC source;
a regulator connected to the output of said full-wave bridge rectifier for
providing a second DC source;
a capacitor connected to said transformer for charging on the negative
swing of said transformer; and
a half-wave rectifier connected to said capacitor for providing a third DC
source.
13. The device of claim 12 further including,
a computer interface means for allowing signals to pass between a computer
and the device; and
a remote control means connected to the computer interface means and the
power control means for sending a power-on or power-off signal to the
power control means responsive to a computer signal, comprised of a remote
transistor connected intermediate the computer interface means and the
power control means for receiving a computer stay-on signal and sending a
responsive power-on signal, a protective network comprised of a resistor
connected intermediate the computer interface and said remote transistor,
a resistor connected in parallel with said remote transistor, and a diode
connected in parallel with said remote transistor, for providing remote
protection, and a hysteresis network connected to the computer interface
means for absorbing spurious signals from the computer interface means.
14. The device of claim 13 further including,
a sense power output means connected to the power input means for supplying
electrical AC power to other devices such as units of a computer system;
and
a power sensor means connected intermediate the power input means and the
sense output means for detecting the flow of power from the power input
means to the sense power output means and for delivering a power-on signal
to the power control means responsive to said flow of power and for
delivering a power-off signal to the power control means response to the
termination of said flow of power, comprised of an optical-isolator
connected intermediate the power input means and the sense power output
means for detecting the flow of power from the power input means to the
sense power output means and for delivering a responsive power-on signal
to the power control means, a limiting network comprised of a plurality of
diodes connected parallel to said optical-isolator and a resistor
connected intermediate said optical-isolator and said diodes, for limiting
the current flow to said optical-isolator, a diode connected in parallel
with said optical-isolator for limiting the voltage, a resistor connected
parallel to said optical-isolator for setting a minimum current threshold
for said optical-isolator, and a low-pass filter connected intermediate
said optical-isolator and the power control means for limiting narrow
transients.
15. The device of claim 14 further including,
a status sensor means connected to the power supply means, the computer
interface means, and the power sensor means for sensing a power-on signal
from the power sensor means and delivering a status signal to the computer
interface means, comprised of a status inverter gate connected
intermediate the power sensor means and the computer interface means for
receiving a power-on signal from the power sensor means, a parallel
transistor connected intermediate said status inverting gate and the
computer interface means for sending a status signal to the computer
interface means, a serial transistor connected intermediate said status
inverting gate and the computer interface means for sending a status
signal to the computer interface means, a resistor connected intermediate
said status inverting gate and said parallel transistor for providing
voltage protection and isolation, a resistor connected parallel with said
parallel transistor to provide voltage division, a resistor connected
intermediate said parallel transistor and the power supply means to
provide voltage pull-up, a resistor connected intermediate said status
inverting gate and said serial transistor to provide isolation, a resistor
connected intermediate said serial transistor and ground to provide
voltage division, a resistor connected intermediate said serial transistor
and the computer interface means to provide voltage protection, and a
resistor connected intermediate said parallel transistor and the power
supply means to provide voltage pull-down.
16. The device of claim 15 further including,
an inhibit means connected to the power supply means, the computer
interface means, and the detection means for receiving an inhibit signal
from the computer interface means and preventing the detection means from
sending a power-on signal to the power control means, comprising of an
inhibit transistor connected intermediate the computer interface means and
said optical-isolator of the detection means for sending an inhibit signal
to said responsive to a computer signal, a resistor connected intermediate
the power supply means and said inhibit transistor for keeping said
inhibit transistor on in the absence of said computer signal, a resistor
connected intermediate the computer interface means and said inhibit
transistor to provide voltage protection, a resistor connected
intermediate the computer interface means and the power supply means for
providing voltage protection, an inverting transistor connected
intermediate the computer interface means and said inhibit transistor for
inverting the computer signal sent to said inhibit transistor, a jumper
connected intermediate the computer interface means and said inhibit
transistor and said inverting transistor for directing the computer signal
to said inhibit transistor or to said inverting transistor, a diode
connected in parallel to said inverting transistor for shunting large
voltages, and a resistor and diode network connected intermediate the
computer interface and said inverting transistor for providing voltage
protection.
17. The device of claim 16 further including,
a surge protection means connected intermediate the power input means and
the power output means for limiting the amount of power flowing from the
power input means, comprised of a fuse connected to the power input means
to provide current protection, a plurality of varistors connected parallel
to the power input means for providing voltage protection, and a choke
inductor connected intermediate two of said varistors for providing
current surge protection.
18. The device of claim 17 further including,
an indicator means connected to the power supply means, the power sensor
means, the detection means and the remote control means for providing the
user with a visual indication of whether the device is on or off and
whether it the power output means were last turned on manually by the
power sensor means or remotely by the detection means or remote control
means, comprised of a LED for providing a visual signal, a flip-flop with
set line connected to the power sensor means and the reset line connected
to the detection means and the remote control means such that said
flip-flop will output a disabling signal when it receives a power-on
signal from the power sensor means and will output a blinking signal when
it receives a power-on signal from the detection means or remote control
means, an oscillator connected intermediate said flip-flop and said LED
for emitting a steady state signal or an oscillating signal responsive to
a disabling signal or a blinking signal respectively, a plurality of
inverting gates connected in parallel intermediate said oscillator and
said LED for controlling said LED, a resistor connected intermediate said
LED and the power supply means for providing voltage protection, and a
resistor connected intermediate said flip-flop and ground for setting said
flip-flop in a steady state when poiwer is initially powered up.
19. The device of claim 18 further including,
a resistor connected parallel to the serial ground and the parallel ground
of the computer interface for providing sufficient ground return so that
the serial port of a computer will function and also for providing
sufficient resistance to prevent damage to the parallel port of a
computer.
20. A telephone activated power controller comprising:
a power input means for receiving electrical AC power;
a power output means connected to the power input means for supplying
electrical AC power to the output devices;
a telephone input means for receiving signals generated by outside
telephonic systems;
a telephone output means for delivering telephonic signals to said output
devices;
a power control means connected intermediate the power input means and the
power output means for controlling the flow of power from the power input
means to the power output means and for disrupting said power flow
responsive to a power-on or power-off signal;
a detection means connected to the telephone input means, telephone output
means, and the power control means for detecting a ring signal from the
telephone input means or an off-hook condition from the telephone output
means and for delivering a power-on signal to the power control means
responsive to said ring signal or said off-hook condition and for
providing a connection between the telephone input means and the telephone
output means and for delivering a power-off signal to the power control
means responsive to an on-hook condition from the telephone output means,
and the detection means comprising a RC load network connected to the ring
line of the telephone input means for providing a ring load, a full-wave
bridge rectifier connected to said RC load network and the tip line of the
telephone input means for rectifying the ring signal and providing a
current path for an off-hook condition signal, an optical-isolator
connected across said full-wave bridge and for sending responsive power-on
and power-off signals to the power control means, a low pass filter
connected intermediate said optical-isolator and the power control means
for eliminating spurious signals, a limiting network comprised of a
plurality of diodes connected in parallel to said optical-isolator and a
resistor connect intermediate said optical-isolator and said diodes for
limiting the current flow to said optical-isolator, a lock-out relay
connected intermediate said full-wave bridge and the tip line of the
telephone output means for controlling the flow of current of the tip line
to the telephone output means, a telephone delay RC network connected to
the power control means for receiving and delaying a relay control signal
when the power output means have been powered up, a lock-out transistor
connected to said lock-out relay for controlling said lock-out relay, a
lock-out inverting gate connected intermediate said telephone delay RC
network and said lock-out transistor for receiving said relay control
signal and controlling said lock-out transistor responsive to said relay
control signal, and a diode connected in parallel to said telephone delay
RC network for allowing immediate receipt of a relay control signal by
said lock-out inverting gate; and
a power supply means connected to the power input means for providing a
plurality of power levels.
21. A telephone activated power controller comprising:
a power input means for receiving electrical AC power;
a power output means connected to the power input means for supplying
electrical AC power to output devices;
a telephone input means for receiving signals generated by outside
telephonic systems;
a telephone output means for delivering telephonic signals to said output
devices;
a power control means connected intermediate the power input means and the
power output means for controlling the flow of power from the power input
means to the power output means and for disrupting said power flow
responsive to a power-on or power-off signal;
a detection means connected to the telephone input means, telephone output
means, and the power control means for detecting a ring signal from the
telephone input means or an off-hook condition from the telephone output
means and for delivering a power-on signal to the power control means
responsive to said ring signal or said off-hook condition and for
providing a connection between the telephone input means and the telephone
output means and for delivering a power-off signal to the power control
means responsive to an on-hook condition from the telephone output means;
a power supply means connected to the power input means for providing a
plurality of power levels;
a computer interface means for allowing signals to pass between a computer
and the controller;
a remote control means connected to the computer interface means and the
power control means for sending a power-on or power-off signal to the
power control means responsive to a computer signal;
a sense power output means connected to the power input means for supplying
electrical AC power to other devices such as units of a computer system;
a power sensor means connected intermediate the power input means and the
sense output means for detecting the flow of power from the power input
means to the sense power output means and for delivering a power-on signal
to the power control means responsive to said flow of power and for
delivering a turn-off signal to the power control means responsive to the
termination of said flow of power;
a status sensor means connected to the power supply means, the computer
interface means, and the power sensor means for sensing a power-on signal
from the power sensor means and delivering a status signal to the
computuer interface means;
an inhibit means connected to the power supply means, the computer
interface means, and the detection means for receiving an inhibit signal
from the computer inerface means and preventing the detection means from
sending a power-on signal to the power control means;
a surge protection means connected intermediate the power input means and
the power output means for limiting the amount of power flowing from the
power input means; and
an indicator means connected to the power supply means, the power sensor
means, the detection means and the remote control means for providing the
user with a visual indication of whether the device is on or off and
whether the power output means were last turned on manually by the power
sensor means or remotely by the detection means or remote control means,
the indicator means including an LED for providing a visual signal, a
flip-flop with set line connected to the power sensor means and the reset
line connected to the detection means and the remote control means such
that said flip-flop will output a dsiabling signal when it receives a
power-on signal from the power sensor means and will output a blinking
signal when it receives a power-on signal from the detection means or
remote control means, an oscillator connected intermediate said flip-flop
and said LED for emitting a steady state signal or an oscillating signal
responsive to a disabling signal or a blinking signal respectively, a
plurality of inverter gates connected in parallel intermediate said
oscillator and said LED for controlling said LED, a resistor connected
intermediate said LED and the power supply means for providing current
limiting protection, and a resistor connected intermediate said flip-flop
and ground for setting said flip-flop in a steady state when power is
initially powered up. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to telephone activated power control
devices and more specifically, to such devices for use with microcomputer
systems.
2. Description of the Prior Art
Microcomputers have become increasingly popular in the business office.
Businesspeople have become more dependent upon microcomputers to manage
their information. The usefulness of microcomputers is increased still
further by adding a modem to allow the computer to transfer and receive
information over telephone lines with other microcomputers or terminals at
remote locations. For example, a businessperson on a trip to a distant
city can call his/her office microcomputer at any time of the day. By
using a portable computer, the person can commuicate with the office
microcomputer to check messages, to send memos or to transfer programs or
data files.
The flexibility of being able to communicate with an office microcomputer
at any time or place does have its drawbacks. In order for the
microcomputer system to be able to answer telephone calls, it must be
continuously left with the power on. If a telephone call is expected in
the evening, this may mean leaving the computer system on all night. The
microcomputers are left running for long periods of time without being
used. This results in increased energy expenses and decreased computer
life.
SUMMARY OF THE PRESENT INVENTION
It is therefore an object of the present invention to provide a telephone
activated power controller for turning on power to a computer system in
response to a telephone ring signal.
It is a further object of the present invention to provide a telephone
activated power controller which turns on power to a computer system when
a telephone line is off-hook and turns off power when the telephone line
is on-hook.
It is another object of the present invention to provide a telephone
activated power controller which allows the modem to refrain from
answering the telephone until the entire computer system is up and
running.
It is a further object of the present invention to provide a telephone
activated power controller which allows the computer system to stay on
after manual turn-off or the telephone goes on-hook to complete required
processing and then allow the computer system to shut itself off.
In an exemplary embodiment of the present invention, the device comprises
an electrical power inlet and a number of power outlets for supplying
power to the parts of the computer system such as the CPU, monitor, modem,
etc. A power surge protection circuit is provided to limit damaging power
surges to the computer system. One of the power outlets is connected to a
power sensor circuit which sends a signal to a power control circuit to
power up the rest of the outlets if power is detected. This allows the
entire computer system to be powered up by turning on one device, such as
the monitor.
The present invention also has a telephone inlet for connection to a
telephone line and an outlet for connection to a modem. When the telephone
rings, or the modem is off-hook, a detector circuit sends a signal to the
power control circuit to power up the power outlets for the computer
system and after a short delay, allows the modem to answer the telephone.
The invention can be connected directly to the computer via a cable
connection. A remote control circuit allows the computer to keep the power
on after hang-up or manual turn-off. A status sensor circuit tells the
computer if the device has been turned on manually or remotely. An inhibit
circuit, when engaged, prevents the device from responding to a telephone
ring or off-hook condition. An indicator light circuit indicates to the
user that the computer system has been remotely turned on.
An advantage of the present invention is that it provides a telephone
activated power controller for turning on power to a computer system in
response to a telephone ring signal.
A further advantage of the present invention is that it provides a
telephone activated power controller which turns on power to a computer
system when a telephone line is off-hook and turns off power when a
telephone line is on-hook.
Another advantage of the present invention is that it provides a telephone
activated power controller which allows the modem to refrain from
answering the telephone until the entire computer system is up and
running.
A further object of the present invention is that it provides a telephone
activated power controller which allows the computer system to stay on
after manual turn-off or telephone hang-up to complete required processing
and then allows the computer to shut itself off.
Another advantage of the present invention is that it provides power surge
protection to the entire computer system.
A further advantage of the present invention is that it has a telephone
inhibit capability that, if activated, prevents the computer from being
turned on when the telephone rings or the modem is off-hook.
Another advantage of the present invention is that it has a status
indicator which indicates if the computer has been turned on remotely.
These and other objects and advantages of the present invention will no
doubt become obvious to those of ordinary skill in the art after having
read the following detailed description of the preferred embodiment which
is illustrated in the various drawing figures.
IN THE DRAWING
FIG. 1 is a diagram of a telephone activated power controller when used in
a computer system; and
FIG. 2 is a circuit diagram of a telephone activated power controller in
accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a diagram of a telephone activated power controller when
used in a computer system and is referred to by the general reference
character 10. The telephone activated power controller 12 receives
electrical power along power line 14. The power controller 12 has a
plurality of six power outlets 16, 17, 18, 19, 20 and 21 for providing
power to the devices in a computer system such as a computer 22, a monitor
24, and a modem 23. The power controller 12 is connected to the telephone
line at telephone inlet 28 and is connected to the modem 23 at telephone
outlet 30. The power controller 12 is also connected to the computer 22 by
a control cable 31 at control cable connection 32.
In operation, the power controller 12 has a number of ways to switch power
to the computer system. Power outlet 20 is a sense outlet. If the monitor
24 plugged-in to power outlet 20 is turned on, then the power controller
12 will immediately supply power to power outlets 16-19, and after
approximately a two second delay, will turn-on power to power outlet 21 to
provide power for the computer 22. If a telephone ring signal is detected
on telephone inlet 28, or if an off-hook condition from the modem 23 is
detected on telephone outlet 30, then the power controller 12 will provide
power to the power outlets 16-19 after a short delay, and after an
additional second delay, to power outlet 21. The power controller 12 will
disconnect power after a delay of five to ten seconds to power outlets
16-19 and 21 when an on-hook condition is detected at telephone outlet 30.
The computer can signal the power controller 12 at control cable
connection 32 to keep the power on after the modem 23 has gone on-hook so
that the computer system can finish its processing, and then the computer
22 can notify power controller 12 to turn the power off.
FIG. 2 illustrates a circuit diagram for the telephone activated power
controller 12 of the present invention. Electrical power, 120 volts A.C.,
50-60 hertz, enters the power controller 12 through a standard
three-pronged plug 42. A power surge protection circuit 44 has the
capability to suppress approximately fifty joules. Fuse 48 is a ten amp
fuse and protects against fire. Varistor 50 is connected across the A.C.
input and acts as stage one of the suppression network. The varistor 50 is
a relatively fast acting shunt that has a maximum clamping voltage of 340
volts and 35 joules of energy absorption. Stage two, the in-line power
choke inductor 52, supplies 50 u.H. of inductance to limit high current
surges. Stage three is varistor 54 which provides a second voltage
clamping stage, so that the resultant suppression capability of the power
surge protection circuit 44 is 50 joules.
The electrical power is then sent to the power outlets 16-21. The sense
power outlet 20 always has power applied to it. The return leg of the
sense power outlet 20 is connected to a current sensor circuit 56.
The current sensor circuit 56 provides a power-on signal output when more
than five watts of power is detected at sense power outlet 20.
Optical-isolator 58 provides the power-on signal output and isolates the
circuit lines so that there is no direct current path. Diodes 60, 62 and
64 provide an asymmetrical current shunt. A resistor 66 limits the current
flowing to the optical-isolator 58 so that it is not damaged. A diode 68
limits the voltage across diodes 60, 62 and 64. A resistor 70 sets the
minimum current threshold required to power-on the device. A voltage drop
across diodes 60 through 64 causes current flow through the light emitting
diode of the optical-isolator 58. The transistor section of the
optical-isolator 58 begins to conduct and charge the low pass filter
capacitor 72. A resistor 74 provides voltage pull-up. The resulting low
voltage power-on signal is sent to a power control circuit 76.
The power control circuit 76 controls power relays 78 and 80 which in turn
provide AC power to the power outlets 16, 17, 18, 19 and 21. A low voltage
signal applied at a pin 82 or 84 at a NAND gate 86 will force pin 87 to
+12 volts. NAND gate 86 is a Schmitt trigger. The +12 volt signal from
NAND gate 86 turns on a NPN transistor 88. A resistor 89 provides
isolation for the transistor 88. Power relay 78 is turned on and AC power
is supplied to power outlets 16, 17, 18 and 19.
The power outlet 21 is used for the CPU and power on to power outlet 21 is
delayed for system protection. When NAND gate 86, pin 87, goes to +12
volts, a RC network composed of a resistor 90 and a capacitor 92 starts to
charge to +12 volts. After one time constant (2.2 seconds), an inverting
gate 94 reaches its positive threshold and switches a pin 96 to low volts.
A PNP transistor 98 is turned on and supplies the low voltage level
required to switch power relay 80 on and supply AC power to power outlet
21.
The power control circuit 76 is turned off when the low voltage signal is
removed from pins 82 or 84. Pin 87 goes to low volts. Transistors 88 and
98 are switched off which in turn switches off power relays 78 and 80 and
removes power from power outlets 16, 17, 18, 19 and 21. A diode 100
provides a fast discharge path for capacitor 92. A diode 102 and a diode
104 protect transistors 88 and 98 from flyback by absorbing stored
magnetic energy when the transistors are turned off by shunting flyback
voltage. A resistor 106 drops some unregulated voltage so that the power
relay 78 does not overheat. There are problems of instability with the
system because computer 22 may momentarily generate a power-on signal at a
pin 107 on control cable connection 32 immediately after the controller 12
has been switched off. A capacitor 108 solves this problem by causing a
slight hysteresis delay in the application of the low volt signal at pin
84.
A power supply circuit 110 supplies a +12 volts regulated, a +12 volts
unregulated, and a -12 volts unregulated to the rest of the controller 12.
The maximum current capacity is 350 milliamps. The total current draw for
the controller 12 is approximately 30 milliamps minimum and 150 milliamps
maximum. A transformer 112 steps the 120 volts AC input down to 12.6 volts
AC and 350 milliamps current capacity output. A full-wave bridge rectifier
114 rectifies the output of transformer 112. A capacitor 116 provides an
unregulated +14 to +16 volts DC source. A three terminal regulator 118
outputs a +12 volts DC source for the controller 12 logic circuits. A
capacitor 120 is charged with the negative swing of the output of
transformer 112. A diode 122 and a diode 124 are used in conjunction with
a capacitor 126 to provide an unregulated -12 volts DC supply.
A detection circuit 128 detects ring signals and off-hook conditions. The
telephone line from the wall is plugged-in to telephone inlet 28. The
telephone inlet is connected in parallel to the telephone outlet 30 except
for a tip line 132 and a ring line 134. The tip line 132 is connected in
series to a full-wave bridge rectifier 146 and a lock-out relay 148. The
rectifier 146 is used to rectify the AC ring voltage and provide an
off-hook current path for an optical-isolator 150. The ring line 134 is
connected to a ring load consisting of a resistor 152 and a capacitor 154.
When there is a ring signal, the ring load causes current to flow through
rectifier 146. The output from rectifier 146 flows through a limiting
network composed of a diode 156, a diode 158, a diode 160, and a resistor
162. The limiting network insures that at low levels, most current goes to
the optical-isolator 150 and at high levels it shunts.
When optical-isolator 150 is turned on a RC network consisting of a
capacitor 164, a capacitor 166, a resistor 168 and a resistor 170
discharges toward low volts. This low-pass filter eliminates spurious
signals resulting from the on/off ring signal. The resultant low voltage
signal is sent to pin 84 of the power control circuit 76 which turns on
power at power relays 78 and 80. When the telepho | | |
