U.S. patent application number 13/161868 was filed with the patent office on 2011-11-10 for load condition controlled power module.
This patent application is currently assigned to iGo, Inc.. Invention is credited to Richard G. DuBose, Walter Thornton.
Application Number | 20110273216 13/161868 |
Document ID | / |
Family ID | 41567992 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110273216 |
Kind Code |
A1 |
DuBose; Richard G. ; et
al. |
November 10, 2011 |
LOAD CONDITION CONTROLLED POWER MODULE
Abstract
In accordance with various aspects of the present invention, a
method and circuit for reducing power consumption of a power module
during idle conditions is provided. In an exemplary embodiment, a
power module is configured for reducing power during idle mode by
disengaging at least one power output from a power input. A power
module may include one or more power outputs and one or more power
module circuits, with power input connected to the power outputs
through the power module circuit(s). The power module circuit may
include a current measuring system, a control circuit, and a
switch. The current measuring system provides an output power level
signal that is proportional to the load at the power output. If
current measuring system behavior indicates that a power output is
drawing substantially no power from the power input, the switch
disengages the power input from the power output.
Inventors: |
DuBose; Richard G.;
(Scottsdale, AZ) ; Thornton; Walter; (Phoenix,
AZ) |
Assignee: |
iGo, Inc.
Scottsdale
AZ
|
Family ID: |
41567992 |
Appl. No.: |
13/161868 |
Filed: |
June 16, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12860618 |
Aug 20, 2010 |
7977823 |
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13161868 |
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12180410 |
Jul 25, 2008 |
7795760 |
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12860618 |
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Current U.S.
Class: |
327/306 |
Current CPC
Class: |
G06F 1/3203 20130101;
G06F 1/26 20130101 |
Class at
Publication: |
327/306 |
International
Class: |
H03L 5/00 20060101
H03L005/00 |
Claims
1. A power module configured as a component of an electronic device
to reduce power consumption during idle operation of the electronic
device, said power module comprising: a power module circuit
configured to receive power from a power input and transmit the
power to at least one power output; a control circuit configured to
receive an output power level signal and control the connection
between said at least one power output and the power input, wherein
said power module circuit disengages transmitting power to said at
least one power output in response to said at least one power
output drawing substantially no power; and a reconnection device
configured to override said control circuit and re-engage said at
least one power output and the power input, and wherein said
reconnection device is further configured to disengage said at
least one power output and the power input.
2. The power module of claim 1, wherein said power module circuit
comprises: a current measuring system configured to monitor current
from the power input, wherein said current measuring system
provides the output power level signal.
3. The power module of 1, wherein said reconnection device is
controlled by at least one of an infra-red signal, a radio
frequency signal, and a signal received through the power
input.
4. The power module of claim 1, wherein said reconnection device is
configured to override a single control circuit.
5. The power module of claim 1, wherein said substantially no power
is approximately 0-1% of a typical maximum output load of said
electronic device at said at least one power output.
6. A power module configured for integration into an electronic
device to efficiently provide power to the electronic device, said
power module comprising: at least one power output configured to
provide power to said electronic device; and a control circuit
disconnects a power input if the current drawn by said at least one
power output is below a threshold level, such that said at least
one power output is effectively disengaged from the power
input.
7. The power module of claim 6, wherein said control circuit tests
a load condition at said at least one power output by reengaging
said at least one power output to said power and determining if the
current drawn by said at least one power output is below the
threshold level.
8. The power module of claim 6, wherein said control circuit
controls said at least one power output individually.
9. The power module of claim 6, wherein said threshold level is a
learned level determined by long term monitoring of a load
condition at said at least one power output.
10. The power module of claim 6, wherein said threshold level is a
percentage of a determined approximate low power level of said
electronic device, and wherein said percentage of said determined
approximate low power level is at least one range of approximately
100-105%, approximately 100-110%, and approximately 110-120%.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/860,618, now U.S. patent Ser. No. ______,
filed on Aug. 20, 2010, and entitled "LOAD CONDITION CONTROLLED
POWER MODULE," which application is a continuation of U.S. patent
application Ser. No. 12/180,410, now U.S. Pat. No. 7,795,760, filed
Jul. 25, 2008, and entitled "LOAD CONDITION CONTROLLED POWER
MODULE", all of which are hereby incorporated by reference.
FIELD OF INVENTION
[0002] The present invention relates to reducing power consumption
in electronic devices. More particularly, the present invention
relates to a circuit and method for reducing power consumption by
disengaging a power output from a power input using a power module
when idle load conditions are present at the power output.
BACKGROUND OF THE INVENTION
[0003] The increasing demand for lower power consumption and
environmentally friendly consumer devices has resulted in interest
in power supply circuits with "green" technology. For example, on
average, a notebook power adapter continuously "plugged in" spends
67% of its time in idle mode. Even with a power adapter which
conforms to the regulatory requirement of dissipating less than 0.5
watts/hour, this extended idle time adds up to 3000 watt-hours of
wasted energy each year per adapter. When calculating the wasted
energy of the numerous idle power adapters, the power lost is
considerable. In addition to power adapters, numerous electronic
devices spend a substantial amount of time plugged-in but not
operating. An opportunity exists for reducing the power lost by
these electronic devices.
SUMMARY OF THE INVENTION
[0004] In accordance with various aspects of the present invention,
a method and circuit for reducing power consumption at a power
output during idle conditions is provided. In an exemplary
embodiment, a load condition controlled power module is configured
for reducing or eliminating power during idle mode by disengaging
at least one power output from a power input. A power module may be
connected to one or more power outputs, and a power input which may
provide alternating current (AC) to the one or more power outputs.
The power module may include a current measuring system, a control
circuit, and a switch. The current measuring system provides an
output power level signal that is proportional to the load at the
power output. In an exemplary embodiment, if behavior of the
current measuring system indicates that at least one power output
is drawing substantially no power from the AC power input, the
switch facilitates disengaging of the power input from such power
output.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] A more complete understanding of the present invention may
be derived by referring to the detailed description and claims when
considered in connection with the Figures, where like reference
numbers refer to similar elements throughout the Figures, and:
[0006] FIG. 1 illustrates a block diagram of an exemplary load
condition controlled power module in accordance with an exemplary
embodiment;
[0007] FIG. 2 illustrates a block diagram of an exemplary load
condition controlled power module in accordance with an exemplary
embodiment;
[0008] FIG. 3 illustrates a block diagram of an exemplary load
condition controlled power module in accordance with an exemplary
embodiment; and
[0009] FIG. 4 illustrates a circuit diagram of an exemplary control
circuit for use within an exemplary load condition controlled power
module in accordance with an exemplary embodiment.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION
[0010] The present invention may be described herein in terms of
various functional components and various processing steps. It
should be appreciated that such functional components may be
realized by any number of hardware or structural components
configured to perform the specified functions. For example, the
present invention may employ various integrated components, such as
buffers, current mirrors, and logic devices comprised of various
electrical devices, e.g., resistors, relays, transistors,
capacitors, diodes and the like, whose values may be suitably
configured for various intended purposes. In addition, the present
invention may be practiced in any integrated circuit application.
However for purposes of illustration only, exemplary embodiments of
the present invention will be described herein in connection with a
sensing and control system and method for use with a power module.
Further, it should be noted that while various components may be
suitably coupled or connected to other components within exemplary
circuits, such connections and couplings can be realized by direct
connection between components, or by connection through other
components and devices located thereinbetween.
[0011] Various embodiments are possible of a power module
configured for reducing or eliminating power during idle mode. In
an exemplary embodiment, a circuit for implementing the power
module is integrated into or otherwise a part of a larger device
and controls power input to the larger device based on various load
conditions. In another exemplary embodiment, the power module is a
component that could be removable or fixed as part of an electronic
device. The power module may be a printed circuit board, a potted
block, an integrated circuit, a MEMS device, or any other structure
configured for implementation in a larger device or system. In
another exemplary embodiment, the power module may be within a
housing configured to facilitate simple installation of the power
module. This embodiment may be added to existing electrical
devices.
[0012] In accordance with various aspects of the present invention,
a power module configured for reducing or eliminating power during
idle mode by disengaging a power input is disclosed. In an
exemplary embodiment, and with reference to FIG. 1, a power module
100 comprises a power input 110, a power output 120 and a power
module circuit 130. Accordingly, power module 100 can comprise any
configuration of system where a power input is received, power is
provided at a power output, and a circuit disengages the power
provided to the power output in order to reduce power
consumption.
[0013] In an exemplary embodiment, power input 110 and power output
120 are 3-pin or 2-pin plugs or receptacles. In another exemplary
embodiment, power input 110 and power output 120 comprise flying
leads for connection to various electrical components. Other
connections may be made by terminal strips, spade connectors, or
fixed connectors mounted on a printed circuit board. However, power
input 110 and power output 120 can be suitably configured in any
other input and/or output configuration. Furthermore, power input
110 may be connected to a 110 volt or 220 volt power source in an
exemplary embodiment.
[0014] In an exemplary embodiment, and with reference to FIG. 2,
power module 100 comprises power input 110 communicatively coupled
to power module circuit 130, which in turn is communicatively
coupled to power output 120. Power output 120 may also be connected
or otherwise coupled to a ground line and a neutral line in one
embodiment. The power module circuit 130 comprises a current
measuring system 231, a control circuit 232, and a switch 233. In
an exemplary embodiment and for illustration purposes, current
measuring system 231 comprises a current transformer 231 having a
primary circuit and a secondary winding. However, current measuring
system 231 may also comprise a resistor with a differential
amplifier, a current sensing chip, a Hall-effect device, or any
other suitable component configured to measure current as now known
or hereinafter devised. Current transformer 231 provides an output
power level signal that is proportional to the load at power output
120. Furthermore, switch 233 connects the primary circuit of
current transformer 231 to power output 120.
[0015] In an exemplary embodiment, control circuit 232 may comprise
at least one of, or a combination of: a latching circuit, a state
machine, and a microprocessor. In one embodiment, control circuit
232 monitors the condition of the secondary winding of current
transformer 231 and controls the operation of switch 233.
Furthermore, in an exemplary embodiment, control circuit 232
receives a low frequency or DC signal from current transformer 231.
The low frequency signal, for example, may be 60 Hz. This low
frequency or DC signal is interpreted by control circuit 232 as the
current required by the load at power output 120.
[0016] Control circuit 232 can comprise various structures for
monitoring the condition of the secondary winding of current
transformer 231 and controlling the operation of switch 233. In an
exemplary embodiment, with reference to FIG. 3, control circuit 232
includes a current sensor 301 and a logic control unit 302. Current
sensor 301 monitors the output of a current measuring system, such
as for example, the secondary winding of current transformer 231,
which is an AC voltage proportional to the load current. Also,
current sensor 301 provides a signal to logic control unit 302. In
one embodiment, the signal may be a DC voltage proportional to the
current monitored by current sensor 301. In another embodiment, the
signal may be a current proportional to the current monitored by
current sensor 301.
[0017] In an exemplary embodiment, logic control unit 302 is
powered by an energy storage capacitor. Logic control unit 302 may
briefly connect the storage capacitor to power input 110 in order
to continue powering logic control unit 302. In another embodiment,
logic control unit 302 may be powered by a battery or other energy
source. This energy source is also referred to as housekeeping or
hotel power; it functions as a low auxiliary power source. In one
embodiment, auxiliary power is taken from power input 110. For
further detail on similar current monitoring, see U.S. Provisional
Application 61/052,939, hereby incorporated by reference.
[0018] In an exemplary embodiment, logic control unit 302 is a
microprocessor capable of being programmed prior to, and after
integration of power module 100 in an electronic device. In one
embodiment, a user is able to connect to logic control unit 302 and
customize the parameters of power module 100. For example, a user
may set the threshold level and a sleep mode duty cycle of power
module 100. Data from power module 100 could be transmitted
regarding, for example, the historical power consumption and/or
energy saved. The bidirectional data transfer between power module
100 and a display device may be achieved through a wireless signal,
such as for example, an infra-red signal, a radio frequency signal,
or other similar signal. The data transfer may also be achieved
using a wired connection, such as for example, a USB connection or
other similar connection.
[0019] In accordance with an exemplary embodiment, control circuit
232 may further comprise a power disconnect 303 in communication
with logic control unit 302. Power disconnect 303 is configured to
isolate logic control unit 302 from power input 110 and reduce
power loss. While isolated, logic control unit 302 is powered by
the storage capacitor or other energy source and logic control unit
302 enters a sleep mode. If the storage capacitor reaches a low
power level, power disconnect 303 is configured to reconnect logic
control unit 302 to power input 110 to recharge the storage
capacitor. In an exemplary embodiment, power disconnect 303 is able
to reduce the power loss from a range of microamperes of leakage
current to a range of nanoamperes of leakage current.
[0020] In another exemplary embodiment, control circuit 232
receives a control signal that is impressed upon power input 110 by
another controller. The control signal may be, for example, the X10
control protocol or other similar protocol. Control circuit 232 may
receive the control signal through the secondary winding of current
transformer 231, from a coupled power input 110, or any other
suitable means configured to couple power input 110 to control
circuit 232 as now known or hereinafter devised. This control
signal may come from within power module 100 or may come from an
external controller. The control signal may be a high frequency
control signal or at least a control signal at a frequency
different than the frequency of power input 110. In an exemplary
embodiment, control circuit 232 interprets the high frequency
control signal to engage or disengage switch 233. In another
embodiment, an external controller may transmit a signal to turn
power module 100 to an "on" or "off" condition.
[0021] In an exemplary embodiment, if behavior of the secondary
winding of current transformer 231 indicates that power output 120
is drawing substantially no power from power input 110, switch 233
facilitates or controls disengaging of the primary circuit of
current transformer 231 from power output 120, i.e., switch 233
facilitates the disengaging of a power source from power outlet
120. In an exemplary embodiment, the secondary winding of current
transformer 231 is monitored for an AC waveform at the AC line
frequency of power input 110, where the AC waveform has an RMS
voltage proportional to the load current passing through the
primary circuit of current transformer 231 to power output 120. In
another embodiment, the AC waveform is rectified and filtered to
generate a DC signal before being received by control circuit 232.
The DC signal is proportional to the load current passing through
the primary circuit of current transformer 231 to power output
120.
[0022] In one embodiment, the phrase "substantially no power" is
intended to convey that the output power is in the range of
approximately 0-1% of a typical maximum output load. In an
exemplary embodiment, switch 233 is configured to control the
connection of the primary circuit of current transformer 231 to
power output 120 and comprises a switching mechanism to
substantially disengage the primary circuit of current transformer
231 from power output 120. Switch 233 may comprise at least one of
a relay, latching relay, a TRIAC, and an optically isolated
TRIAC.
[0023] By substantially disabling the primary circuit of current
transformer 231, the power consumption at power output 120 is
reduced. In one embodiment, substantially disabling power output
120 is intended to convey that the output signal of the secondary
winding of current transformer 231 has been interpreted by control
circuit 232 as sufficiently low so that it is appropriate to
disengage switch 233 and remove power from power output 120.
[0024] In another exemplary embodiment, and with reference to FIGS.
2 and 3, power module circuit 130 further comprises a reconnection
device 234, which is configured to enable the closure of switch 233
through logic control unit 302. The closure of switch 233
reconnects power output 120 to the primary circuit of current
transformer 231 and power input 110. In an exemplary embodiment,
reconnection device 234 comprises a switch device that may be
closed and opened in various manners. For example, reconnection
device 234 can comprise a push button that may be manually
operated. In one embodiment, the push button is located on the face
of power module 100. In another embodiment, reconnection device 234
is affected remotely by signals traveling through power input 110
that control circuit 232 interprets as on/off control. In yet
another embodiment, reconnection device 234 is controlled by a
wireless signal, such as for example, an infra-red signal, a radio
frequency signal, or other similar signal.
[0025] In an exemplary embodiment, and with reference to FIGS. 3
and 4, power module circuit 130 further comprises a reconnection
device memory state 304. Reconnection device memory state 304 is
configured to indicate whether reconnection device 234 was recently
activated so that logic control unit 302 can determine the circuit
conditions upon power up. In the exemplary embodiment, reconnection
device memory state 304 comprises a capacitor C5, which charges
when reconnection device 234 is activated. Logic control unit 302
can then measure the voltage on capacitor C5 as an indication of
whether reconnection device 234 was activated. In one exemplary
embodiment, reconnection device memory state 304 provides a digital
reading to the PB1 input of logic control unit 302. If there is
sufficient voltage at capacitor C5, the PB1 input reads a "1". If
there is insufficient voltage at capacitor C5, the PB 1 input reads
a "0". The determination of what voltage is sufficient is dependent
in part on the ratio of resistors R6 and R7 and can be interpreted
by logic control unit 302, as would be known to one skilled in the
art. Capacitor C5 serves to store the state of reconnection device
234 until the voltage of capacitor C5 can be read by logic control
unit 302.
[0026] In accordance with another exemplary embodiment, switch 233
is automatically operated on a periodic basis. For example, switch
233 may automatically reconnect after a few or several minutes or
tens of minutes, or any period more or less frequent. In one
embodiment, switch 233 is automatically reconnected frequently
enough that a battery operated device connected to power module 100
will not completely discharge internal batteries during a period of
no power at the input to the connected device. After power output
120 is reconnected, in an exemplary embodiment, power module
circuit 130 tests for or otherwise assesses load conditions, such
as the power demand at power output 120. If the load condition on
power output 120 is increased above previously measured levels,
power output 120 will remain connected to the primary circuit of
current transformer 231 until the load condition has returned to a
selected or predetermined threshold level indicative of a "low
load". In other words, if the power demand at power output 120
increases, power is provided to power output 120 until the power
demand drops and indicates a defined idle mode. In an exemplary
embodiment, the determination of load conditions at re-connect are
made after a selected time period had elapsed, for example after a
number of seconds or minutes, so that current inrush or
initialization events are ignored. In another embodiment, the load
conditions may be averaged over a selected time period of a few
seconds or minutes so that short bursts of high load average out.
In yet another exemplary embodiment, power module 100 comprises a
master reconnection device that can re-engage all power outputs 120
to power input 110.
[0027] In an exemplary method of operation, power module 100 has
switch 233 closed upon initial power-up, such that power flows to
power output 120. When load conditions at power output 120 are
below a threshold level, control circuit 232 opens switch 233 to
create an open circuit and disengage power output 120 from the
input power signal. This disengaging effectively eliminates any
idle power lost by power output 120. In one embodiment, the
threshold level is a predetermined level, for example approximately
one watt of power or less flowing to power output 120.
[0028] In an exemplary embodiment, different power outputs 120 may
have different fixed threshold levels such that devices having a
higher power level in idle may be usefully connected to power
module 100 for power management. For example, a large device may
still draw about 5 watts during idle, but would never be
disconnected from power input 110 if the connected power output 120
had a threshold level of about 1 watt. In various embodiments,
certain power outputs 120 may have a higher threshold levels to
accommodate high power devices, or lower threshold levels for lower
power devices.
[0029] In another embodiment, the threshold level is a learned
level. The learned level may be established through long term
monitoring by control circuit 232 of load conditions at power
output 120. A history of power levels is created over time by
monitoring and may serve as a template of power demand. In an
exemplary embodiment, control circuit 232 examines the history of
power levels and decides whether long periods of low power demand
were times when a device connected at power output 120 was in a
low, or lowest, power mode. In an exemplary embodiment, control
circuit 232 disengages power output 120 during low power usage
times when the period of low power matches the template. For
example, the template might demonstrate that the device draws power
through power output 120 for eight hours, followed by sixteen hours
of low power demand.
[0030] In another exemplary embodiment, control circuit 232
determines the approximate low power level of the electronic device
connected at power output 120, and sets a threshold level to be a
percentage of the determined approximate low power level. For
example, control circuit 232 may set the threshold level to be
about 100-105% of the approximate low power level demand. In
another embodiment, the threshold demand may be set at about
100-110% or 110-120% or more of the approximate low level power
demand. In addition, the low power level percentage range may be
any variation or combination of the disclosed ranges.
[0031] Having disclosed various functions and structures for an
exemplary power module configured for reducing or eliminating power
during idle mode by disengaging power input, a detailed schematic
diagram of an exemplary power module 400 can be provided in
accordance with an exemplary embodiment of the present invention.
With reference to FIG. 4, in an exemplary embodiment of power
module 400, power module circuit 130 comprises current transformer
231, current sensor 301, logic control unit 302, power disconnect
303, reconnection device memory state 304, and switch 233.
[0032] In one embodiment, current transformer 231 and current
sensor 301 combine to measure the current from power input 110 and
convert said current to a proportional DC voltage that can be read
by logic control unit 302. Furthermore, switch 233 may comprise a
latching relay, e.g., relay coil K1, that provides a hard
connect/disconnect of power input 110 to power output 120 after a
command from logic control unit 302. Switch 233 alternates between
open and closed contacts. Furthermore, switch 233 holds its
position until reset by logic control unit 302, and will hold
position without consuming any power in a relay coil K1.
[0033] In an exemplary embodiment, logic control unit 302 comprises
a microcontroller that receives input of the current in the power
input line, controls the state of switch 233 and reads or otherwise
assesses the state or position of the contacts of reconnection
device 234 and switch 233. In addition, logic control unit 302
learns and stores the power profile for an electronic device
connected to power output 120. In another exemplary embodiment,
power module circuit 130 further comprises reconnection device 234
and reconnection device memory state 304. Reconnection device 234
is activated to turn on power output 120 when power module circuit
130 is first connected to power input 110 or when full power is
needed immediately at power output 120. Reconnection device memory
state 304 is configured to indicate to logic control unit 302
whether reconnection device 234 was recently activated.
[0034] In an exemplary embodiment, power disconnect 303 comprises a
network of transistors Q1, Q2, Q3 which are used in conjunction
with zener diodes Z1, Z2 to condition power input 110 to a safe
level suitable for logic control unit 302 and isolate logic control
unit 302 from power input 110. In another embodiment, power
disconnect 303 comprises relays in addition to, or in place of, the
transistors of the prior embodiment.
[0035] Initial connection of power module 400 involves connecting
power module 400 to a power source, which may be AC or DC. In an
exemplary method, upon initial plug-in of power module 400 to a
power source, all circuits of power module circuit 130 are dead and
switch 233 is in the last position or state set by logic control
unit 302. This initial condition may or may not provide power to
power output 120. When all the circuits are dead, there is no
current flow into power module circuit 130. This is due to the
isolation provided by power disconnect 303 and reconnection device
234 in a normal, open position. In an exemplary embodiment, power
disconnect 303 comprises transistors Q1, Q2, Q3 and capacitor C3.
In this state, only leakage current will flow through transistors
Q1, Q2 and the leakage current will be on the order of
approximately tens of nanoamperes. Furthermore, current transformer
231 provides dielectric isolation from primary side to secondary
side so that only small leakage current flows due to the
inter-winding capacitance of current transformer 231.
[0036] With continued reference to FIG. 4, in an exemplary
embodiment and for illustration purposes, a user may reconnect the
circuit using reconnection device 234 to establish a current path
through diode D1, zener diode Z1, reconnection device 234, resistor
R4, diode D6, and zener diode Z3. Diode D1 serves to half-wave
rectify the AC line to drop the peak to peak voltage in half. Zener
diode Z1 further reduces the voltage from diode D1, for example to
about 20 volts. Zener diode Z3 and resistor R4 form a current
limited zener regulator that provides an appropriate DC voltage at
the VDD input to logic control unit 302 while reconnection device
234 is held. In addition, capacitor C2 smoothes the DC signal on
zener diode Z3 and provides storage during the contact bounce of
reconnection device 234. Capacitor C2 is sized to provide
sufficient storage during the start-up time of logic control unit
302, and capacitor C2 in combination with resistor R4 provides a
fast rising edge on the VDD input to properly reset logic control
unit 302. Furthermore, diode D5 isolates capacitor C2 from
capacitor CS so the rise time constant of capacitor C2 and resistor
R4 is not affected by the large capacitance of capacitor CS. When
capacitor CS is powering logic control unit 302, the current of
capacitor CS passes through diode D5. Diode D6 serves to isolate
the voltage on capacitor C2 when reconnection device 234 is
released. This allows the voltage stored on capacitor C5 during the
closed time of reconnection device 234 to be retained when
reconnection device 234 is open and inform logic control unit 302
of the open condition.
[0037] In an exemplary method, if reconnection device 234 is
activated for a few milliseconds, logic control unit 302 is
configured to initialize and immediately set up to provide its own
power before reconnection device 234 is released. This is
accomplished from voltage doubler outputs VD1-VD3 and ZG1 of logic
control unit 302. First, output ZG1 is driven high to turn on
transistor Q2. With transistor Q2 on, a current path is established
through resistor R3 and zener diode Z2 providing a regulated
voltage at the drain of transistor Q1. This regulated voltage is
similar to that produced by zener diode Z3 and is appropriate for
the VDD input of logic control unit 302. Second, after the voltage
on zener diode Z2 has stabilized for a few microseconds, outputs
VD1-VD3 of logic control unit 302 begin switching to produce a gate
drive signal to turn on transistor Q1. The signals produced by
outputs VD1-VD3 and components including capacitor C3, transistor
Q3, capacitor C4, diode D3 and diode D4 produce a voltage at the
gate of transistor Q1 that is about twice the voltage on VDD input
of logic control unit 302. This voltage doubling turns transistor
Q1 on hard. Once transistor Q1 is on, the voltage at zener diode Z2
charges capacitor CS. In an exemplary embodiment, capacitor CS is a
large storage capacitor that is used to power logic control unit
302 when reconnection device 234 is not being activated. After
capacitor CS has been charged for a few milliseconds, outputs
VD1-VD3 and ZG1 return to a rest state and transistors Q1 and Q2
are turned off. In this embodiment, logic control unit 302 is
operating off the stored charge in capacitor CS and not drawing
power from power input 110. When reconnection device 234 is no
longer active, capacitor CS will continue to power logic control
unit 302.
[0038] If power output 120 is idling and drawing substantially no
power, logic control unit 302 may be able to disengage from drawing
power and enter a "sleep" mode. In an exemplary method, and with
further reference to FIG. 4, when logic control unit 302 is
operating from the stored energy in capacitor CS, a timing function
is enabled in logic control unit 302 that uses capacitor C6 to
perform the timing function. Capacitor C6 is briefly charged by the
CAPTIME output of logic control unit 302 and over time capacitor C6
discharge rate will mimic the decay of the voltage on capacitor CS.
Once capacitor C6 voltage at input CAPTIME reaches a low level,
logic control unit 302 will set the state of outputs VD1-VD3 and
ZG1 to again recharge capacitor CS from the AC line. This process
repeats over and over so power is never lost to logic control unit
302. The recharge process takes only a few milliseconds or less to
operate, depending on the size of capacitor CS.
[0039] Furthermore, in an exemplary method, when logic control unit
302 is not busy recharging capacitor CS, switching relay K1, or
measuring power drawn from power output 120, logic control unit 302
is operating in a deep sleep mode that stops all, or substantially
all, internal activity and waits for capacitor C6 to discharge.
This sleep mode consumes very little power and allows the charge on
storage capacitor CS to persist for many seconds. If reconnection
device 234 is activated during the sleep mode, capacitor C5 will be
recharged and logic control unit 302 will resume normal operation
and set or reset relay K1. Alternatively, if capacitor C6 voltage
falls too low, logic control unit 302 will again recharge capacitor
CS and then return to sleep mode.
[0040] While an electronic device is in an idle mode, power module
100 may continue to monitor for changes in the power drawn by the
electronic device. In an exemplary method, while logic control unit
302 continuously goes in and out of sleep mode to re-power itself,
logic control unit 302 will also periodically test the power being
drawn from power output 120. The period of power testing is much
greater than that of capacitor CS charging and, for example, may be
only tested every ten or more minutes. In accordance with an
exemplary method, there are at least three possible outcomes from
the result of power testing: 1) the device is operating and the
switch is not in standby condition, 2) the device is not operating
but the switch is not in a standby condition, or 3) the switch is
in a standby condition.
[0041] For the outcome when the device is operating and the switch
is not in a standby condition, relay K1 has been previously set to
deliver power to power output 120 and power testing shows an
appreciable load current is being drawn by the electronic device
connected. An "appreciable load" may be defined by some fixed value
programmed into logic control unit 302, or it may be the result of
a number of power tests and be the typical load current for this
electronic device. A power test result here will be interpreted as
normal conditions and logic control unit 302 will go back into
sleep mode cycling until another time period, such as ten minutes,
has passed when the power test will be made again. In another
exemplary embodiment, the duration of the sleep mode cycling is
determined by a user. For example, a user may set the sleep mode
duration to be one, two, or five minutes and may do so using a
dial, a digital input, a push button, keypad or any other suitable
means now know or hereinafter devised.
[0042] For the outcome when the device is not operating but the
switch is not in a standby condition, relay K1 has been previously
set to deliver power to power output 120 and power testing shows a
negligible load current being drawn by the device connected. The
"negligible load" may be some fixed value programmed into logic
control unit 302, or it may be the result of a number of power
tests and be the typical minimum found for this electronic device.
In either case the action taken by logic control unit 302 will be
to set relay K1 to an open condition by using outputs RELAY1-RELAY2
of logic control unit 302 to energize relay coil K1. The state of
relay K1 is determined by logic control unit 302 testing for the
presence of resistor R5 at RELAY3, since logic control unit 302 may
not know the previous state of relay K1, for example, starting from
power off state.
[0043] For the outcome when the switch is in a standby condition,
that is, relay K1 has been set to remove power from power output
120, logic control unit 302 must set relay K1 to a closed condition
to allow AC power to be applied to the power output. In an
exemplary method, once relay K1 is set, a period of time is allowed
to elapse before the power testing is done. This delay allows for
the electronic device attached to power output 120 to initialize
and enter a stable operating mode. Power measurements may now be
made over some period of time to determine if the electronic device
is in a low or high power state. If a high power state is
determined, relay K1 remains set. If a low power state is
determined, relay K1 is reset to open condition and power is again
removed from power output 120. Also, logic control unit 302 will
again begin sleep mode cycling and power testing after a determined
time period, for example, every ten minutes.
[0044] If a user wants to operate a device that is connected to
power output 120 and that power output is turned off, in an
exemplary embodiment, activating reconnection device 234 will
immediately wake logic control unit 302 from sleep mode. Since the
wake up was from the activation of reconnection device 234 and not
due to power testing or capacitor CS recharging, logic control unit
302 will immediately set relay K1 to closed position to power the
electronic device connected to power output 120.
[0045] In addition to the embodiments described above, various
other elements may be implemented to enhance control and user
experience. One way to enhance user control is to allow a user to
select the operating mode of a power output. In an exemplary
embodiment, power module 100 further comprises a "Green Mode"
switch that enables or disables the "green" mode operation. The
green mode switch may be a hard, manual switch or it may be a
signal to logic control unit 302. "Green" mode operation is the
disengaging of power output 120 from Power input 110 when
substantially no load is being drawn at power output 120. A user
may use the green mode switch to disenable green mode operation on
various power outputs when desired. For instance, this added
control may be desirable on power outputs that power devices with
clocks or devices that need to be instantly on, such as a fax
machine.
[0046] In one embodiment, power module 100 includes LED indicators,
which may indicate whether a power output is connected to the power
line and drawing a load current. The LED indicators may indicate
that whether a power output is active, that is, power is drawn by
an electronic device and/or the power output has power available
even if an electronic device is not connected. In addition, a
pulsing LED may be used to show when power testing is being done or
to indicate the "heartbeat" of sleep mode recharging.
[0047] In another embodiment, power module 100 comprises at least
one LCD display. The LCD display may be operated by logic control
unit 302 to indicate the load power being provided to power output
120, for example during times of operation. The LCD may also
provide information about the power saved or power consumed by
operating power module 100 in or out of a "green" mode. For
example, LCD may display the sum total of watts saved during a
certain time period, such as the life of power module 100 or in a
day.
[0048] Various embodiments may also be used to enhance the
efficient use of the power module and/or individual power outputs
in the power module. One such embodiment is the implementation of a
photocell or other optical sensor monitored by logic control unit
302. The photocell determines whether light is present in the
location of power module 100 and logic control unit 302 can use
this determination to disengage power output 120 depending on the
ambient light conditions. For example, logic control unit 302 may
disengage power output 120 during periods of darkness. In other
words, the power outputs of the power module may be turned off at
night. Another example is devices do not need power if located in a
dark room, such as an unused conference room in an office. Also,
the power outputs may be turned off when the ambient light
conditions exceed a certain level, which may be predetermined or
user determined.
[0049] In another embodiment, power module 100 further comprises an
internal clock. Logic control unit 302 may use the internal clock
to learn which time periods show a high power usage at power output
120. This knowledge may be included to determine when a power
output should have power available. In an exemplary embodiment, the
internal clock has quartz crystal accuracy. Also, the internal
clock does not need to be set to an actual time. Furthermore, the
internal clock may be used in combination with the photocell for
greater power module efficiency and/or accuracy.
[0050] The present invention has been described above with
reference to various exemplary embodiments. However, those skilled
in the art will recognize that changes and modifications may be
made to the exemplary embodiments without departing from the scope
of the present invention. For example, the various exemplary
embodiments can be implemented with other types of power module
circuits in addition to the circuits illustrated above. These
alternatives can be suitably selected depending upon the particular
application or in consideration of any number of factors associated
with the operation of the system. Moreover, these and other changes
or modifications are intended to be included within the scope of
the present invention, as expressed in the following claims.
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