U.S. patent application number 09/115843 was filed with the patent office on 2001-06-07 for bus-powered computer peripheral with supplemental battery power to overcome bus-power limit.
Invention is credited to GILBERT, TIMOTHY G..
Application Number | 20010003205 09/115843 |
Document ID | / |
Family ID | 22363721 |
Filed Date | 2001-06-07 |
United States Patent
Application |
20010003205 |
Kind Code |
A1 |
GILBERT, TIMOTHY G. |
June 7, 2001 |
BUS-POWERED COMPUTER PERIPHERAL WITH SUPPLEMENTAL BATTERY POWER TO
OVERCOME BUS-POWER LIMIT
Abstract
A computer system typically includes a central computer and
several peripherals, such as a mouse and a printer, which
communicate with the computer via a communications channel known as
a serial bus. The serial bus may also supply a limited amount of
power to some peripherals. Unfortunately, the power limit compels
high-power peripherals to include independent power supplies, an
arrangement which increase their complexity and cost. Accordingly,
one embodiment of the present invention provides a bus-powered
peripheral that includes a controller, a rechargeable battery, and
a voltage regulator or recharge circuit. The recharge circuit
monitors data on a serial bus, recharges the battery during
inactive periods, and allows the battery to supplement bus power
during active periods, thereby overcoming the power limit of the
serial bus.
Inventors: |
GILBERT, TIMOTHY G.;
(VERMILLION, SD) |
Correspondence
Address: |
SCHWEGMAN LUNDBERG WOESSNER & KLUTH
P O BOX 2938
MINNEAPOLIS
MN
55402
|
Family ID: |
22363721 |
Appl. No.: |
09/115843 |
Filed: |
July 15, 1998 |
Current U.S.
Class: |
713/320 |
Current CPC
Class: |
G06F 1/266 20130101 |
Class at
Publication: |
713/320 |
International
Class: |
G06F 001/26; G06F
001/28; G06F 001/30; G06F 001/32 |
Claims
1. A computer peripheral for communicating with a computer, the
computer peripheral comprising: a power terminal for coupling to an
external power source; a data terminal for coupling to the
computer; a voltage regulator coupled to the power terminal; a
rechargeable battery coupled to the voltage regulator; a
primary-function module coupled to the voltage regulator; and a
controller coupled to the voltage regulator and responsive to
signals at the data terminal to switch the voltage regulator
between a charge mode that charges the rechargeable battery and a
supply mode that supplies energy from the rechargeable battery to
the primary-function module.
2. The computer peripheral of claim 1, wherein the primary-function
module includes components of a printer, scanner, fax machine, or
speaker.
3. The computer peripheral of claim 1, wherein the peripheral
includes a USB port coupled to the power terminal and the data
terminal.
4. The computer peripheral of claim 1, wherein the external power
source is part of the computer.
5. A USB bus-powered peripheral comprising: a USB port having two
USB power terminals for coupling to a pair of USB power lines and
having two USB data terminals for coupling to a pair of USB data
lines; a voltage regulator coupled to the two USB power terminals;
a rechargeable battery coupled to the voltage regulator; a
primary-function module coupled to the voltage regulator, the
primary-function module including components of a printer, scanner,
fax machine, or speaker; and a controller coupled to the voltage
regulator and responsive to signals at the USB data terminals to
switch the voltage regulator between a charge mode that charges the
rechargeable battery and a supply mode that supplies energy from
the rechargeable battery to the primary-function module.
6. A system comprising: a computer; a bus for communicating data
and power according to a bus specification; and a peripheral
coupled to the computer via the bus to receive data and power, the
peripheral including: a primary-function module; and a rechargeable
battery circuit coupled to the bus to store energy and responsive
to power demands of the primary-function module to transfer stored
energy to the module.
7. The system of claim 6, wherein the battery circuit includes: a
voltage regulator coupled to the bus and the primary-function
module; a rechargeable battery coupled to the voltage regulator;
and a controller coupled to the voltage regulator and responsive to
signals on the bus to switch the voltage regulator between a charge
mode that charges the rechargeable battery and a supply mode that
supplies energy from the rechargeable battery to the
primary-function module.
8. A computer peripheral comprising a rechargeable battery that
stores energy during inactive periods for use during active
periods.
9. The computer peripheral of claim 8, further comprising: a
communications port having two power terminals for coupling to a
pair of power lines and having two data terminals for coupling to a
pair of data lines, the power lines having a predetermined power
limit; a voltage regulator coupled to the power terminals and the
rechargeable battery; a primary-function module coupled to the
voltage regulator; and a controller coupled to at least one of the
two data terminals and to the voltage regulator, the controller
responsive to signals at the data terminals, indicating an inactive
period, to switch the voltage regulator to a charge mode during
which it charges the rechargeable battery and responsive to signals
at the data terminals, indicating an active period, to switch the
voltage regulator to a battery supply mode during which it
transfers energy from the rechargeable battery and from the power
lines to the primary-function module, thereby providing the
primary-function module power in excess of the predetermined power
limit.
10. The computer peripheral of claim 8, wherein the
primary-function module includes components of a printer, scanner,
fax machine, or speaker.
11. A power-extension peripheral for connection between a computer
and a computer peripheral, the power-extension peripheral
comprising: a power terminal for coupling to an external power
source; a data terminal for coupling to the computer; a voltage
regulator coupled to the power terminal and having an output
terminal for coupling to the computer peripheral; a rechargeable
battery coupled to the voltage regulator; and a controller coupled
to the data terminal and to the voltage regulator and responsive to
signals at the data terminal to switch the voltage regulator
between a charge mode that connects the rechargeable battery to the
power terminal for recharge and a supply mode that connects the
rechargeable battery and the power terminal to the output terminal
for supplying power from both the battery and the external power
source to the computer peripheral.
12. A system comprising: a computer for processing data; a bus,
coupled to the computer, for communicating data; a power supply for
supplying a limited amount of power; a power-extension peripheral
coupled to the computer via the bus and to the power supply and
including a supplemental power source; and a computer peripheral
coupled to the bus via the power-extension peripheral to receive
power from the power supply and the supplemental power source,
thereby receiving more than the limited amount of power.
13. The system of claim 12, wherein the power supply is part of the
computer.
14. The system of claim 12, wherein the supplemental power source
comprises a rechargeable battery and the power-extension peripheral
further comprises: a power terminal coupled to the power supply; a
data terminal coupled to the computer to receive signals; a voltage
regulator coupled to the power terminal and the rechargeable
battery, and having an output terminal coupled to the computer
peripheral; and a controller coupled to the voltage regulator and
responsive to signals at the data terminal to switch the voltage
regulator between a charge mode that connects the rechargeable
battery to the power terminal for recharge and a supply mode that
connects the rechargeable battery and the power terminal to the
output terminal for supplying power from both the battery and the
power supply to the computer peripheral.
15. A computer peripheral comprising: a pair of power terminals for
receiving a limited amount of power; a data terminal for
communicating with a computer; a primary-function module coupled to
the power terminals and the data terminal to perform a primary
function; a rechargeable battery coupled to the power terminals and
responsive to power demands of the primary-function module to
provide supplemental power to the primary function module during
high-power-demand periods and to store excess power during
low-power-demand periods.
16. A computer peripheral comprising: a pair of power terminals for
receiving a limited amount of power; a data terminal for receiving
data from a computer; a primary-function module coupled to the
power terminals and the data terminal to perform a primary
peripheral function, the primary-function module including a first
portion that receives power only through the power terminals and a
second portion that receives power through the power terminals; and
a rechargeable battery coupled to the power terminals and to the
second portion of the primary-function module so that the second
portion receives power concurrently from both the rechargeable
battery and the power terminals.
17. The computer peripheral of claim 16, wherein the first portion
of the primary-function module is responsive to signals at the data
terminal to selectively activate or deactivate the second portion
of the primary-function module, and wherein the battery is
responsive to deactivation of the second portion to store energy
transferred via the power terminals.
18. The computer peripheral of claim 16, wherein the first portion
of the primary-function module includes control logic and circuits
responsive to signals at the data terminal to operate the second
portion, and the second portion of primary-function module includes
one or more transducers for converting electrical energy into
another form of energy.
19. A method of operating a computer peripheral connected to a
computer via a bus, the method comprising: transferring power via
the bus to the computer peripheral; operating at least a part of
the peripheral with power transferred via the bus; and charging a
battery with at least a portion of the power transferred via the
bus.
20. The method of claim 19 further including operating at least a
part of the peripheral with power transferred via the bus and with
power derived from the charged battery.
Description
FIELD OF THE INVENTION
[0001] The present invention concerns computer systems and computer
peripherals, particularly a system that recharges a battery-powered
peripheral through a serial bus.
BACKGROUND OF THE INVENTION
[0002] Computer systems, particularly personal computers, typically
include a central processing unit and a number of peripherals, or
auxiliary devices, such as monitors, keyboards, mice, disc drives,
printers, scanners, and even cameras, which communicate with the
central processing unit. The central processing unit and the
peripheral devices are usually connected via a two-way
communications channel, known as a serial bus, which carries a
stream of electrical pulses representing a sequence of ones and
zeros. The serial bus may also carry electrical power for operating
one or more peripherals.
[0003] Serial bus parameters, or specifications, are usually
standardized not only to reduce the number of communications
protocols, or procedures, a computer must understand, but also to
simplify matching of computers and peripherals. Examples of serial
bus specifications include Apple desktop bus (ADB), Access.bus
(A.b), Institute of Electrical and Electronic Engineers (IEEE)
P1394, Concentration Highway Interface (CHI), and GeoPort.
[0004] Within the past few years, a new serial bus specification,
called the Universal Serial Bus (USB) Specification, has been
developed to work with peripherals that require higher data rates,
more flexibility, or less complexity than previously available in
standard serial busses. A Universal Serial Bus, a serial bus that
operates according to the USB Specification, has a maximum data
rate of 12 million bits per second (12 Mbps), and carries as much
as 2.5 watts of electric power to operate USB peripherals (that is,
USB-compliant peripherals).
[0005] One problem with the USB and other serial bus specifications
are the power limits they impose on bus-powered peripherals,
peripherals that operate almost entirely on power carried by a
serial bus. Because of the power limits, high-power peripherals,
such as printers or speakers, that require more than the power
limit for a particular serial bus must use separate, external power
supplies. Unfortunately, external power supplies add expense and
complexity to peripherals.
[0006] Accordingly, there is a need for a better way of powering
high-power computer peripherals.
SUMMARY OF THE INVENTION
[0007] To address this and other needs, the present invention
provides a peripheral with a rechargeable battery that stores
energy during inactive periods for use during active periods. In
one exemplary embodiment, the peripheral includes a voltage
regulator for coupling to a pair of bus power lines; a controller
coupled between the voltage regulator and one or more bus data
lines; and a rechargeable battery coupled to the voltage regulator.
In operation, the controller switches the battery between a charge
mode and a supply mode according to signals received through the
bus data lines. The charged battery supplements the power available
through the bus power lines, thereby providing more power for
operating the peripheral than otherwise available over the bus
power lines alone.
[0008] Another embodiment packages the supplemental power
capabilities as a power-extension or power-enhancement peripheral
for connection between a computer and another peripheral. And, yet
another embodiment, which lacks a controller, relies on
rechargeable battery coupled in parallel with a primary-function
module of the peripheral. The rechargeable battery responds
automatically to power demands of the primary-function module to
supply supplemental power during high-power-demand periods and to
store excess power during low-power-demand periods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram of a first computer system
including a computer peripheral with rechargeable battery;
[0010] FIG. 2 is a block diagram of a second computer system
including a power-extension peripheral connected between a computer
and a USB bus-powered peripheral;
[0011] FIG. 3 is a block diagram of another embodiment of a
computer peripheral having a rechargeable battery; and
[0012] FIG. 4 is a block diagram of another embodiment of a
computer peripheral having a rechargeable battery.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] The following detailed description, which references and
incorporates FIGS. 1-4, describes and illustrates specific
preferred embodiments, or versions, of the invention. These
embodiments, offered not to limit but only to exemplify and teach
the invention, are shown and described in sufficient detail to
enable those skilled in the art to practice the invention. Thus,
where appropriate to avoid obscuring the invention, the description
may omit certain information known to those of skill in the
art.
[0014] FIG. 1 shows a personal computer system 10, which includes a
personal computer 20, a Universal Serial Bus (USB) 30, and a USB
peripheral 40. Computer 20, preferably a Gateway 2000 personal
computer from Gateway 2000, Inc. of North Sioux City, S. Dak.,
includes a processor 22; a memory 24, which includes Universal
Serial Bus (USB) communications software 241; a power supply 26,
which converts 110 VAC to 5 volts DC; and a USB port 28, which
follows the USB Specification 1.0 (Final Revision of Nov. 13, 1995)
or an earlier or subsequent version. The USB. Specification is
incorporated herein by reference.
[0015] USB port 28 connects to USB serial bus 30. USB serial bus 30
includes a USB cable 32 which terminates at one end (computer end)
with USB connector 34 and at its other end (peripheral end) with
USB connector 36. In accord with the USB Specification, cable 32,
which has 90 ohm impedance, includes four insulated wires 321-324.
Wires 321 and 322 provide respective nominal voltages of 5 volts
and return ground, and carry a maximum of 2.5 watts of power. Wires
323 and 324 are differential data lines that carry differential
data signals as well as an NRZI-encoded clock signal. Connector 34,
at the computer end of cable 32, mates with USB port 26, and
connector 36, at the peripheral end, mates with USB port 42 of USB
peripheral 40.
[0016] Port 42 includes not only power terminals 421 and 422 which
connect respectively to wires 321 and 322, but also data terminals
423 and 424 which connect respectively to wires 323 and 324. USB
peripheral 40 additionally includes an interface-controller module
44, a voltage regulator (or recharge circuit) 46, a rechargeable
battery 48, and a primary-function module 49. Interface-controller
module 44 is connected to data terminals 423 and 424 of USB port
42. Power terminals 421 and 422 (of port 42) connect to voltage
regulator 46. Voltage regulator 46 connects to battery (or
energy-storage device) 48, which includes one or more
energy-storage cells (not shown), preferably long-life rechargeable
lithium, nickel-cadmium, zinc-bromine, or alkaline-manganese cells
with minimum charging hysteresis. In addition, voltage regulator 46
includes output terminals 461 and 462 which are connected to
primary-function module 49.
[0017] Primary-function module 49 includes the primary circuits and
components necessary for the USB peripheral to perform its intended
function. For example, USB peripheral 40 may be a printer, and
module 49 would thus include the buffers, print heads, motors, etc.
for a complete printer. Alternatively, USB peripheral 40 may also
be a pair of speakers, with each speaker including a
digital-to-analog converter, an amplifier, volume controls, and an
audio transducer. Ultimately, the invention encompasses any type of
computer peripheral, including high-power peripherals that require
more power than available through bus 30.
[0018] In operation, interface-controller module 44 monitors and
decodes data received at data terminals 423 and 424. If it receives
data indicating or invoking an inactive period, for example, data
instructing that the peripheral be turned off, it sends a control
signal to voltage regulator 46. The control signal invokes a charge
mode in voltage regulator 46. In the charge mode, voltage regulator
46 diverts power away from primary-function module 49 to battery
48, thereby charging battery 48.
[0019] On the other hand, if interface-controller module 44
receives data indicating or invoking an active period, such as data
instructing that the peripheral be turned on, it sends a different
control signal to voltage regulator 44. The different control
signal invokes a supply mode during which module 44 couples battery
48 to primary function module 49, allowing battery 48 to provide
supplemental power to primary-function module 48. Thus, during the
supply mode, primary-function module 48 receives power not only
from computer 20 (via bus 30), but also from battery 48, thereby
overcoming the 2.5 watt power limit of bus 30.
[0020] In another embodiment, voltage regulator 46 monitors power
drawn by primary-function module 49 against that available through
serial bus 30. If excess power is available, that is, if more power
is available than power being drawn, voltage regulator 46 invokes a
variable-trickle-charge mode which charges battery 49 at a rate
proportionate to, or at least dependent on, the amount of excess
power. Consequently, battery 49 keeps a charge sufficient to
consistently satisfy the peak power demands of primary-function
module 48.
[0021] FIGS. 2-4 show three other embodiments of the invention. In
particular, FIG. 2 shows a system 100 in which USB peripheral 50
functions solely as an in-line power-extension (or
power-enhancement) peripheral for a separate high-power peripheral
70. The major difference between peripherals 40 and 50 is that
peripheral 50 lacks primary-function module 49 and outputs power
and data through a USB connector 64. Connector 64 is connected via
a USB cable 66 to another USB connector 68. Connector 68 engages
USB port 72 of peripheral 70. Port 72, substantially identical in
structure and function to port 42, has four output terminals
721-724 connected to a primary-function module 79. Module 79 is
substantially identical in structure and function to module 49.
[0022] In operation, the peripheral 50 operates much like
peripheral 40. More precisely, port 42 and controller 44 of
power-extension peripheral 50 decode and monitor data on bus 30. If
controller 44 detects data indicating or invoking an inactive
period for peripheral 70, it directs regulator 46 to divert power
away from connector 64 and thus away from peripheral 70 to charge
battery 48. On the other hand, if controller 44 detects data
indicating or invoking an active period for peripheral 70, it
allows battery 48 to provide supplemental power through connector
64, cable 66, and connector 68 to peripheral 70, thereby overcoming
the 2.5 watt power limit of bus 30. Furthermore, two or more
substantially similar power-extension peripherals can be connected
in parallel to provide even more supplemental power to a given
high-power peripheral.
[0023] FIG. 3 shows another embodiment of high-power peripheral 40,
designated 80. Peripheral 80 includes many of the same or similar
components as peripheral 40, namely USB port 42, voltage regulator
46, battery 48, and primary-function module 49. Notably, peripheral
80 lacks controller 44 for monitoring and detecting bus data
indicative of active or inactive operating periods. Instead,
peripheral 80 has battery 48 connected in parallel with output
terminals 461-462 of voltage regulator 46 to "sense" the current
drawn by primary-function module 49. During low power-demand
periods, excess bus power (that is, bus current not drawn by module
49) charges battery 48 as necessary, and during high power-demand
periods, battery 48 supplies supplemental power to primary-function
module 49. Thus, like peripherals 40 and 70, peripheral 80
overcomes the 2.5 watt power limit of bus 30.
[0024] FIG. 4 shows another embodiment of high-power peripheral 40,
designated 90. Peripheral 90 includes many of the same or similar
components as peripheral 40, specifically USB port 42, voltage
regulator 46, battery 48, and primary-function module 49. However,
primary-function module 49 has been divided, preferably according
to power requirements, into two portions: a low-power portion 49a
which receives power and data only from USB port 42, and a
high-power portion 49b which receives power from both USB port 42
and battery 48.
[0025] Low-power portion 49a preferably includes control logic and
circuits for operating high-power portion 49b, and, high-power
portion 49b includes one or more transducers for converting
electrical energy into another form of energy essential to the
function of the peripheral. For example, high-power portion 49b
could include a motor which converts electrical energy to kinetic
energy, or a light source which converts electrical energy to
light, or a speaker which converts electrical energy to an acoustic
energy. However, the scope of the invention encompasses any
convenient division of a peripheral into first and second portions
with the second portion connected to receive supplemental battery
power.
[0026] Peripheral 90 has battery 48 connected in parallel with
output terminals 461-462 of voltage regulator 46 to sense the
current load of only the high-power portion 49b, which is activated
or deactivated via a control line from low-power portion 49a. Thus,
when low-power portion 49a activates high-power portion 49b,
battery 48 supplies supplemental power to primary-function module
49, and when low-power portion 49b deactivates high-power portion
49b, excess bus power charges battery 48. Therefore, like
peripherals 40, 50, and 80, peripheral 90 overcomes the power limit
of bus 30.
[0027] Conclusion
[0028] The present invention provides several embodiments of
bus-powered peripherals, including a power-extension peripheral,
which overcome the 2.5 watt power limitation imposed by the USB
Specification. Ultimately, the invention, applicable to any
communications bus, eliminates the need to provide a separate
external power supply in many high-power computer peripherals.
[0029] The embodiments described above are intended only to
illustrate and teach one or more ways of practicing or implementing
the present invention, not to restrict its breadth or scope. The
actual scope of the invention, which encompasses all ways of
practicing or implementing the invention, is defined only by the
following claims and their equivalents.
* * * * *