Field of the invention
The present invention relates to smart, energy aware low powered information
display system and the use of that with granular power management and control.
Background Art
BACKGROUND OF INVENTION
The field of invention includes the energy harvesting circuit with autonomous
power usage management and control for energy storage elements; super
capacitor charging circuit to charge graphene based super capacitor using battery
while the supply of power to bistable display device is done using high charge
density graphene based super capacitor that gets charged in very less time from
battery due to very low ESR. The time taken by the ultra low powered information
display system to discharge super capacitor, which can run for hours
independently, is large as compared to charging the super capacitor. This time
difference is due to ultra low power consumption of information display system,
optimization of power consumption at software level and fast charging capability
of graphene super capacitor. As the low powered display device used can retain
the displayed information on screen without using any power so this time
difference can be very large if the information updated on the display is done
periodically and the frequency of information update is less. This time difference
as being large is being utilized to replenish the energy, using energy harvesting
circuit that is capable of working with high impedance sources like solar panels,
lost by the battery in the charging the super capacitor.
US20080037306 discloses an apparatus for driving an LCD display, comprising: a
dc power supply for outputting energy at a supply voltage; a dc-to-dc converter
for converting the supply voltage of the power supply into a converted voltage; a
driver for driving the display; an energy storage device for storing energy
outputted by the converter at the converted voltage, a storage device for providing
stored energy to the display driver; and a controller for controlling the timing of
an active phase, an inactive phase, and a driving phase. In the present invention
device and method for supplying a display, such as a liquid crystal display, for
example a bistable LCD, with drive voltages for extremely low power operation.
The method enables, for instance, the use of small displays operating with coin
(button) batteries, including devices such as watches, calculators, 5 etc. with a
desired longer battery lifetime. Implementation of the inventive method and
circuit serves to counter the quiescent current draw of the voltage conversion
circuitry.
10 US7692411 B1 discloses The present invention is also an apparatus for delivering
power to a load, the apparatus comprising of at least one energy source, a charge pump for
boosting a voltage of charge collected from the energy source, a control module, a battery,
and one or more supercapacitors for charging the battery and delivering power to a load,
wherein the control module controls charging of the supercapacitors to a threshold voltage
15 by the charge pump. The voltage of the collected charge is preferably less than half of the
threshold voltage, and optionally 55,approximately one fourth of the threshold voltage.
The control module is preferably programmable. The supercapacitors are preferably
switched to being arranged in series, for delivering power at a delivery voltage higher
than the threshold voltage to the load or to charge the battery. The delivery voltage is
20 optionally approximately twice the threshold voltage. The control module preferably
adjusts the rate of switching capacitors in the charge pump based on a parameter selected
from the group consisting of the charging rate of the supercapacitors and the power level of the
energy source.
25 US 8952665 discloses the low power display device is an indoor solar powered, low
power consumption display unit with wireless radio network connectivity. The solar
panel of the low power display device 200 is capable of collecting any source of light
energy, including indoor lighting. In the present subject matter low power display
device can alternatively be powered by parasitic energy, energy generated by opening
30 and closing a door, energy collected from ambient radio frequency noise, or other
energy sources. Energy can be obtained from a moving door, for example, through a
DC motor turned through gearing by the motion of the door. The power storage device
4
305 stores energy from the solar panel 210. In some implementations, the power
storage device 305 (e.g., an ultracapacitor) is selected to provide sufficient charge
storage capacity to eliminate the need for including a battery in the low power
display device 200. A Cholesteric LCD allows the displayed image to stay fixed on
the display indefinitely regardless of whether or not power is supplied 5 to the low
power display device. This type of persistent display is referred to as a bistable
display.
US9318069B2 discloses apparatus and methods for dynamically adjusting a
10 device display refresh rate in response to various graphical presentation operation
determinations within a display system to conserve exhaustible device resources.
In accordance with some aspects of the disclosure, a variable refresh rate can be
dynamically employed at a liquid crystal display (LCD) of a consumer electronic
device (e.g., a laptop computer, a tablet computer, a mobile phone, or a music
15 player device). The present US9318069 Patent talking about variable refresh rate
of screen depend ending on the image type.
Another prior art US2015024874 discloses saving power by shifting the content of
image from RAM to cache when the display on screen remains US 7614011
20 discloses a power saving method for self-luminous displays and an apparatus
thereof, comprises determining active and inactive portions of a display screen.
The inactive portions of the display screen are modified in accordance with
criteria to save power by reducing energy consumption of the inactive portions
while the active portions remain powered. This document specifically based on
25 OLED Technology
US 20060061563 discloses a power-management methods and systems for
electronic appliances and, in particular, to power-management methods and
systems that take advantage of power-consumption characteristics of display
30 components based on display components that directly emit light without the need
for backlighting, such as organic-light-emitting-diode-based display components,
5
in order to avoid unnecessary power consumption while displaying textual and
graphic information. The present subject matter also based on OLED technology.
Further, US8749541 disclose a display device includes a timing controller
configured to control a rate at which frames are refreshed 5 on a display. For
example, the timing controller may cause the frames to refresh at different rates,
depending on the image data received at the timing controller. In one mode,
frames on the display device are refreshed at a first rate. In another mode, frames
on the display device are refreshed at a lower, second rate. Further, a pixel
10 formatter may format image data in different modes depending on the image data
received by the timing controller. The said Patent basically talks about variable
refresh rate of screen depend ending on the image type.
In EP2216771 Patent the invention relates to a display device and display system
15 thereof, and more particularly to a display device with a wireless communication
module and lower power consumption and display system thereof. In the said
Patent Display Technology is different & Processor used is not low powered.
SUMMARY OF THE INVENTION
20 One aspect of the invention is related to ultra low powered energy efficient
information display system with autonomous energy harvesting, energy storage,
control and supply of power with energy optimized design, ultra low powered
processing unit (MCU) with different low power modes as well as internal power
management feature in order to reduce the power consumption of overall device
25 to the minimal possible level and electronic paper display. The device gets into
normal active running state only when it receives anything on wake up interrupts
else remain in low power deep sleep mode with ultra low power consumption.
The different power modes are defined at run time based on the application needs
that helps in optimization of power usage. This helps in increasing the life of the
30 primary (super capacitor) and in turn secondary (Battery) storage elements and the
information display device can run for longer duration of time on primary storage
element of given capacity in a single recharge.
6
In current scenario transport sector majorly deploys LED, LCD, TFT based and
other similar types screen for displaying all kind of passenger information. These
screens are put at metro stations, railway terminals, bus stations, depots, ports,
airport terminals, toll plaza, and ferry terminals for patrons. 5 These displays are
continuously being used to provide relevant different kind of information to the
patrons/passengers. These devices require continuous supply of high power and
consume lot of energy. In the coming years the transport market is expected to
grow significantly leading to the significant growth in the requirement of patron
10 information displays. With the increase in number of these kinds of displays being
deployed in larger quantity the consumption and usage of electricity will also see
a steep rise. The sheer number will put huge pressure in the energy sector to fulfill
the ever increasing demand for energy. This infrastructure development will put
lot of pressure on the energy sector that in turn lead to increase in greenhouse gas
15 emissions. These trends are clearly unsustainable and we must seize the solutions
at hand. Ambitious actions and use of power efficient systems are essential to
avoid dangerous climate change, as well as worsening air quality in cities across
the globe. Energy sector has seen a lot of development, innovation and emerging
new and better readily available technologies like autonomous ultra low power
20 integrated circuits; ultra low powered microcontroller and processor unit with
energy efficient power mode with granular internal power management; energy
efficient solar panels which work in ambient light and solar light; high charge
density graphene based super capacitors and graphene batteries with reduced
internal resistance, less voltage drop, very less power loss, ultra high surface area,
25 high charge carrier mobility and longer operational life time and gets recharged
very quickly; electrophoretic displays which can retain its content on screen even
when all power sources are off, this means that display is only consuming power
when something is changing on display; ultra low powered communication
methods with very low quiescent current in wait mode; energy aware intelligent
30 software and power efficient operating systems with power intelligent power
management features; smart and dynamic power management framework. With
7
the advent of these readily available technology it is quite possible to design zero
powered smart energy aware information display system in which the consumed
energy is less as compared to energy harvested by environmental sources of
energy on the scale of time. The energy used in charging the graphene super
capacitor is replenished by the renewal source of energy by harvesting 5 and storing
the captured charge in the rechargeable battery. These application/device deploys
different methods depending upon the use case to reduce power usage like
switching between different power modes, turn off any peripheral modules that
are not needed or used in any power mode, using CPU in high speed run mode for
10 processing intensive application and configuring energy saving peripherals to run
independently to collect and save data without waking up CPU. It consumes very
less power and further intelligently optimizes the power usage during normal
operation while power consumption is further reduced to significant amount while
in deep sleep mode. The zero powered energy aware low powered information
15 display can be deployed at metro stations, bus stations, airport terminals, ferry
terminals, railway platforms, and other similar places.
This invention helps in reduction of operational and infrastructure cost, decreases
emissions, reduces pressure on non-renewal sources, and further reduces
20 implementation and maintenance cost which is beneficial to the society and at the
same time it also contributes towards preserving resources of our planet Earth.
DETAILED DESCRIPTION OF INVENTION
25 The present invention describes the technologies relating to advance high density
energy storage in form of fast charging graphene battery and graphene super
capacitor, low powered bistable display device that retains the displayed contents
when switched off, and smart energy aware ultra low powered microprocessing
unit with granular power management and control based on the usage or
30 application such that the whole system runs on ultra low power making it ideal to
run on renewal sources of energy and to reduce overall average power
consumption to a large extent.
8
In general one aspect of the invention described can be embodied in one of more
energy harvesting circuit that consists of ultra low power boost converter/charger
connected to one or more storage element with a controllable switch and is
optimized for high impedance sources such as solar panel or thermo electric
generators with battery management, battery protection, and ultra 5 low quiescent
current; a rechargeable graphene based battery or graphene enhanced battery/ or a
regular battery for storing energy generated from the solar panels in a controlled
manner; High efficiency synchronous switched-mode super capacitor charger
circuit with input over voltage protection, thermal protection, automatic sleep
10 mode for low power consumption and internal loop compensation for charging
super capacitor using battery; high charge density and fast chargeable graphene
based super capacitor used for delivering regulated power to ultra low powered
display device through a buck converter. The super capacitor is connected to
battery through super capacitor charger circuit and to ultra low power boost
15 converter/charger through a controllable switch; a buck converter with an
externally programmable regulated supply of power and low quiescent current to
preserve the overall efficiency of the power management stage compared to step
down converter.
20 Another aspect of the invention described in this specification can be embodied in
a smart ultra low power display system that includes low power consumption
micro processing unit (MCU) with multiple granular low power modes to provide
optimization based on application requirement, energy saving peripherals that are
intelligent enough to process data without waking up CPU, low power timers, low
25 power serial communication, low power wireless communication, low external
component count, wake up interrupts for supporting interrupts when system
clocking is disabled in low power modes and ability to gate off peripheral clocks
to reduce power consumption. The MCU is also connected to energy harvesting
unit to control the charging circuit and know the status of energy level of battery,
30 super capacitor charging circuit to control the charging of super capacitor by
switching it on and off as per the energy level of both storage elements and buck
9
converter to control the regulated power supply to the bistable display i.e. when it
is required to refresh display screen then only power is supplied else power is
disconnected. The MCU also diverts the harvested energy from solar panel to
primary or secondary storage elements as per their power level through a switch;
and ultra low powered electrophoretic/ bistable displays of different 5 sizes that
consumes power only when the display is refreshed as the image on screen is
retained even when all power sources are removed.
Another but important aspect of the subject matter described in this specification
10 can be embodied in the software implementation method to reduce consumption
of power during operational as well as in other power modes. The implementation
includes autonomous switching between different power modes as per the usage
of the application, internal granular power management that can be used to control
the power usage. The system also controls and manages energy saving peripherals
15 that are intelligent enough to collect and store data without waking up CPU core.
The information display system always remains in deep sleep mode and only
wakes up to enter into other power modes according to the usage and requirement
of application. For example all CPU intensive processing like running deciding
algorithms is done in high-speed run mode while peripherals modules remain in
20 inactive state and all data communication where CPU is not required is done using
peripherals modules, like serial port and radio communication, with the help of
different DMA channels without waking up the CPU. Power supply to external
peripherals is also controlled by the firmware.
25 Other embodiment of the subject matter described in invention is implementation
of whole system such that to achieve equilibrium between energy consumption
and energy production/harvesting (by high impedance sources like solar panels,
ambient light etc.) based on the scale of time. The power aware and event driven
system design of low powered display device has the ability to minimize the
30 energy consumption by changing the energy configuration and usage of the
system such as changing power modes or gating clocks to the hardware modules
etc. as per the requirement. As the overall energy consumption of information
10
display is minimized and harvesting efficiency of solar cells has improved with
time therefore one is able to harvest and replenish the energy that is used in
running the low powered information display system.
The switchable multiple energy harvesting circuit depending, 5 upon their
configuration, stores the captured charge from the solar light into the fast
rechargeable graphene based battery and/or the graphene super capacitor
depending upon the power level of the both primary and secondary storage
element. The super capacitor further provides power to intelligent energy aware
10 display device for changing the display content. Due to specific nature and
property of graphene based super capacitors like it gets charged in very less time,
say 2 to 10 minutes using battery. When smart energy efficient low powered
display is connected to the super capacitor it can drive the ultra low power display
devices for large duration of time depending upon frequency of transaction on the
15 screen, type of processing done by ultra low power processing unit and time taken
to return from normal to ultra low power mode. The time difference between
charging super capacitor by battery and discharging of super capacitor due to load
is very large. The time difference been large can easily replenish the energy of
battery that is used in charging the super capacitor. Using this method one can
20 achieve the zero powered patron information display system that doesn’t require
any external non-renewal power sources. This smart zero powered information
display system can replace all LED, LCD and other similar system used in the
transport industry to reduce usage and dependency on non-renewal source of
energy, decrease pressure on non renewal energy sector, decrease cost of
25 operation significantly and off course the emission (carbon footprint) making the
environment greener.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
30 Figure -1 (one solar panel)
Smart Energy Aware Low Power Display System
Brief Description Figure-1:Block diagram of Smart Energy Aware low powered
11
display system with single energy harvesting circuit. Single harvesting unit
primarily charges the battery.
Figure -2 (Two solar panels)
Smart Energy Low Power 5 Display System
Brief Description Figure-2: Block diagram of Smart Energy Aware low powered
display system with two energy harvesting circuit. One charges the battery and
another charges the super capacitor
10
BEST MODE OF INVENTION
The low powered energy aware display device/system mainly consists of one
(Figure-1) or more (Figure-2) energy harvesting circuit for charging different
15 storage element (i.e. battery and/or super capacitor), super capacitor charging
circuit specifically for charging graphene based super capacitor from battery, lowpowered
bistable display that is capable of retaining the content without power,
energy aware ultra low power micro processing unit with power management
features to control the power usage of micro processor itself, to manage, protect
20 and control the charging of battery as well as super capacitor depending upon the
power level of both and controllable supply of regulated power to low-powered
bistable display.
Energy harvesting circuit in turn consists ultra low powered efficient boost
25 converter/charger controller capable of working with high impedance sources like
solar panels, energy storage element specifically is a fast charging graphene based
battery or grapheme enhanced battery or it can be any other high-density energy
storage element like Lithium ion battery or hybrid Lithium ion-battery or thin film
battery or any battery of similar kind. In another possible configuration/design (as
30 in Figure-2) where an additional unit of energy-harvesting circuit can also be used
to charge graphene based super capacitors directly to replenish the energy used by
bistable display to refresh screen while changing content. In this
12
configuration/design one harvesting circuit that is directly connected to battery
charges the rechargeable battery while another that is connected to super capacitor
charges the super capacitor, where in the super capacitor can also be charged from
battery through super capacitor charging circuit.
5
The super capacitor charging circuit that is responsible for charging graphene
super capacitor from battery consists of boost converter, super capacitor charging
integrated circuit, low powerbuck converter with programmable regulated voltage
supply and high energy density graphene based super capacitor storage known for
10 very low ESR as well as fast charging and discharging feature as its important
property. The low power micro processing unit has some input/output signals
attached to boost converter, super capacitor charger and buck converter in order to
control the power usage and charging of graphene super capacitor by enabling and
disabling the signals. At the same time it also controls the power supply to the
15 load (i.e. bistable display) with the help of attached signal to buck converter.
The battery charges the grapehene based super capacitor in very less time while
super capacitor can power the energy aware low powered display for longer
duration of time, as display device’s average power consumption is very low. The
20 time difference between charging and discharging super capacitor is used to
replenish the energy transferred by the battery to the super capacitor with the help
of efficient solar panels.
Working Example:
25
For instance if it takes T1 seconds to charge super capacitor by battery and in
T2seconds the super capacitor gets discharged due to low powered display then
T1 < T2. The constant supply of power at a given lux for duration equivalent to
time difference between charging and discharging of super capacitor (i.e. T2-T1)
30 can replenish the energy of battery used in charging the super capacitor as the
discharging time (T2) of super capacitor is far greater than charging time (T1) of
super capacitor. The time T2 to discharge the super capacitor can further be
13
increased by connecting one more energy harvesting circuit which charges the
super capacitor directly using environment energy. In this configuration the
supercapacitor’s used energy in running the load can be replenished directly using
solar energy. This is achieved due to two major reasons (a) the bistable display
only needs power, which is very low, when it is required to 5 change the display
content. (b) The rate of energy harvesting is equivalent to rate of energy
consumption by bistable display when it is refreshing its screen. The rate of
harvesting energy can be also increased or improved by using solar panel capable
of providing higher power. Under this circumstance energy aware low powered
10 display becomes self-sufficient in terms of power generation and usage. In this
configuration (Figure -2) T2 time will become too large and energy harvesting
circuit responsible for charging the battery get sample time to be able to recharge
the graphene battery to the programmable upper threshold value.
15 The low powered display device hardware and software has been designed
keeping in mind the power usage factor. All integrated circuits and peripheral
components used in the apparatus have very low quiescent current, less current
leakage when inactive and can work at very low voltage. The main idea behind it
is to increase the graphene based super capacitor life using aggressive energy
20 conservation techniques without compromising the functionality and efficiency of
the information display device. The low powered information display system
majorly can be divided into three main sections.
The first section is energy harvesting section that consists of ultralow powered
25 boost converter/charger device with battery management feature and rechargeable
energy storage like graphene batteries or graphene enhanced batteries or lithium
ion-battery or lithium polymer batteries or thin film battery or batteries of similar
nature. In one configuration (Figure-1) the boost converter/charger is connected to
rechargeable battery and supercapacitor through a microprocessor controlled
30 switch for switching the connection between primary and secondary storage
element depending upon the power level of both. The energy harvesting circuit
has a highly efficient boost converter/charger to extract power from low voltage
14
output harvesters such as thermo electric generators or solar panels. It also
autonomously monitors maximum and minimum voltages against the user
programmed under voltage and over voltage to prevent any damages to the battery.
With the help of attached signal, the microprocessor can be informed by toggling
the flag when the voltage of the energy storage battery drops to 5 below a critical
level or reaches the upper threshold value. Once voltage of the battery drops, the
critical level of the MCU (microprocessor unit) triggers load shedding by
switching off some external peripherals/circuits like super capacitor charging
circuit by itself moving into deep sleep mode and putting all its internal peripheral
10 modules into doze/sleep mode. This prevents the system from entering into under
voltage condition. The preferred energy storage device used in this section is
graphene enhanced battery or graphene based batteries as they have minimal
voltage drop, less power loss, more power efficiency, longer application time,
more available power, more available current and longer operational life. In
15 addition to this they are charged and discharged faster and stores more energy due
to extreme power density as compared to other conventional storage elements like
lithium ion-batteries or other conventional super capacitors. This configuration
makes the charging section highly intelligent and power efficient with faster
charging rate and higher energy storage. Using graphene based batteries, or
20 graphene-enhanced batteries make system durable and safe as they don’t contains
toxic elements, has high temperature tolerance and are bio degradable in nature.
As the maintenance requirement of these kinds of batteries is very low, due to this
they have very high operational life. Although other rechargeable energy storage
devices can also be used like Lithium-ion with graphene anode or Lithium ion or
25 thin film batteries or similar nature energy storage with little reduced charging
efficiency. This storage element (Battery) also acts as back up energy storage
during unavailability of solar energy and it can run the systems for days without
depending on any external source of energy. The energy harvesting circuit uses an
integrated temperature sensor to monitor temperature and once the temperature
30 reaches its threshold, the charging ceases. Once the temperature of device drops
below threshold the charging resumes operation. So the charging circuit
15
autonomously provides thermal as well as overvoltage protection after referring to
the user programmable threshold values. When the battery reaches its lower
threshold value the MCU keeps the super capacitor charging circuit off to provide
under voltage protection to the battery. The charging of super capacitor can only
take place when battery has enough stored energy to charge super 5 capacitor. In
case the battery is charged fully till programmed upper threshold level, the solar
panel is switched to initiation of charging the graphene super capacitor that
provides power to low powered information display system. This helps in running
the low powered display directly on sunlight the whole day without requiring any
10 alternative source of energy. This helps in reducing the battery usage to minimal,
hence, increasing the battery life as well as giving ample time to charge the
battery using environmental sources of energy. In another configuration (Figure-
2) multiple harvesting units, each connected directly to battery and super capacitor
respectively can be used to charge primary and secondary battery independently
15 from solar energy.
The second section is super capacitor charging circuit that consists of fully
integrated synchronous boost converter with high power density, switched-mode
super capacitor charger controller that works in two phases (constant current and
20 constant voltage) with low current sleep mode (< 15 micro Ampere), low powered
buck converter with programmable regulated voltage output, and specifically only
graphene based super capacitor pack for primary energy storage. This whole
circuit is controlled by the microprocessor unit and is used to fast charge the
primary storage using the secondary storage element i.e. battery. Once the
25 graphene super capacitor reaches its threshold, the whole supercapacitor charging
circuit is switched off by disabling the boost converter circuit that in turn switches
off the charging of supercapacitor. As soon as the capacitor reaches it’s
programmed critical voltage, the microprocessor enables the super capacitor
charging circuit for recharging the super capacitor from secondary energy storage
30 element i.e. the battery. The charging is done at high current so as to charge super
capacitor in very less time (Almost 3 to 10 Minutes), after that once again super
16
capacitor charging circuit is switched off. During the day time, when battery is
fully charged, the solar energy is used to charge the super capacitor with the help
of which low powered display can be run full day without any external alternative
source of energy or batteries present in the system. In case the secondary storage
element i.e. the battery reaches lower threshold value, the 5 super capacitor
charging circuit is in disable state. If both storage elements (i.e. primary and
secondary) reach the lower energy threshold value then the load is shed by
switching off all the integrated circuits including the bistable display device and
the MCU goes into deep sleep mode. The MCU only wakes up when rechargeable
10 battery reaches the upper threshold value and is able to recharge the super
capacitor for normal functioning of information display system.
The third section is low powered display that consists of ultra low powered micro
controller/processor unit with inbuilt power management and control, and a low
15 powered bistable/ electrophoric display which retains the image even when all
power sources are removed. This means that the display is consuming power only
when something is changing on the screen, owing to introduction of new data. The
microcontroller unit / micro processing unit has very low active power
consumption, different power modes from high speed run mode to a very low
20 power run mode including deep sleep mode, reduced processing time due to high
speed run mode, very fast wake-up time, low leakage wakeup unit, ultra low
standby current, autonomous peripheral operations, energy efficient peripherals.
This help in optimizing and reducing power consumption during the runtime by
deploying different software based energy saving techniques. The system runs on
25 energy aware event driven software with built in power management and efficient
control of power modes as well as use of energy efficient coding to drastically
reduce power consumption. The internal power management feature provided is
used to control the power usage by controlling the frequency, clock source, clock
gating of peripherals, use of compute mode and execution from flash & RAM
30 depending upon the application needs and requirements. The micro processing
unit only comes in normal active state when some processing is required to be
17
done otherwise the apparatus remains in inactive low powered state and bistable
display remains in power off mode. For example: the device is capable of
receiving data, to be displayed on low powered serial port or Bluetooth and
storing it in the buffer without waking the mcu core. Once complete data is
collected for processing the mcu, the core comes in high 5 speed run mode for
processing and decoding data, then processed data is sent to be displayed and after
that CPU core switches off, the bistable display before going into sleep mode.
Before sending the data to the display screen, it is powered up and after refreshing
the screen, power to screen is removed further saving the energy. This technique
10 reduces the power consumption to a significant value. The power consumption
also depends upon the number of times the screen is refreshed in a day. As the
frequency of transaction decreases so is the power consumption as most of the
time the system remains in deep sleep mode. The device is capable of displaying
text and images that can be sent by any host or server on wired and wireless
15 communication medium.
The basic invention is to reduce the overall power consumption of the device
intelligently by controlling the power usage so that it can run for longer duration
of time on energy stored in super capacitors giving enough time to the secondary
20 energy storage element (battery) to replenish its energy that was used to charge
graphene super capacitor by energy harvesting circuit.

WE CLAIM:
1. An energy aware low power display system using a solar panel comprising
of;
An autonomous energy harvesting circuit connected to battery and/or
super capacitor through a microprocessor controlled switch to selectively
pass energy harvested by solar panel to primary or secondary storage
element based on the power level of storage elements,
a super capacitor charging circuit that can be switched off or on by a
microprocessor using enable or disable input/output signal depending upon
the threshold value of super capacitor and is used to charge graphene
based fast charging super capacitor from rechargeable battery,
a low powered energy efficient processing device powered by the
graphene based super capacitor through programmable regulated power
supply and configured to manage power consumption at a granular level in
a low power display system,
selectively switching the low power display system between a wake up
mode of operation when some data is received its communication channel
for processing and a sleep mode of operation when in ideal state;
the system is configured to display an information sought via wireless
network or other means on a display panel, the display panel gets powered
on and display is refreshed, as and when new information is received, else
the display stays in dormant or switched off mode leading to minimal
power consumption.
30
2. A low power display system as claimed in claim 1, wherein the power
levels of storage elements are programmable over voltage and under
voltage threshold values.
19
3. A processing device as claimed in claim 1 consists of ultra low powered
microprocessor unit that runs an energy aware event driven software with
inbuilt granular power management and control.
4. The display unit as claimed in claim 1 is a low 5 powered bistable/
electrophoric display which retains the image even when all power sources
are removed.
5. The super capacitor as claimed in claim 1, is graphene based super
10 capacitor which is specifically used as it has very less voltage drop, high
charge and discharge rate, very less power loss, more available power,
more operational life and very less ESR as compared to any other
conventional super capacitor. This super capacitor can be charged in few
minutes by high-density fast discharging battery or any other source of
15 power.
6. The battery (secondary storage element) as claimed in claim 1 is
preferably rechargeable graphene-based battery or rechargeable graphene
enhanced battery.