FORM 2

THE PATENTS ACT  1970
(39 of 1970)
&
THE PATENTS RULES  2003

COMPLETE SPECIFICATION
(See section 10  rule 13)

“A system of flexible power distribution scheme for high availability systems”

Tejas Networks Limited
2nd floor  GNR Tech Park  46/4  Garbebhavi Palya 
Kudlu Gate  Hosur main road 
Bangalore 560 068  Karnataka  India

The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the Invention
The present invention concerns power supply systems and pertains particularly to the power distribution scheme for high availability systems.

Background of the Invention
Power supplies for electronic equipment often need to provide more than one possible source of power to a system load  for reasons of redundancy. The multiple power sources might have the same power characteristics or they might be different from each other. For example  different power sources might be configured to provide power at different voltages. Where the power sources are different  or at least where one is typically preferred over another  the preferred power source is typically designated as the primary power source and the other is designated as the secondary power source.
When both a primary and secondary power source are required  a power supply should be designed so that when the primary source fails  the secondary source will immediately take over without an interruption in the operation of the equipment being powered.
To the best of the inventor’s knowledge  power distribution architectures in use today either use Dual Buses with power supplies feeding the buses independently for redundancy or have a single bus with multiple power supplies feeding them in current sharing mode as shown in figure 1(a-b). Two-bus implementation requires the system to carry power supplies that have two times the power requirement of the system. This is the most reliable way of implementation. The single bus scheme typically uses n+1 scheme where the total power supply capacity is slightly above the power requirement of the system.
The above mentioned architectures require twice the power supply capacity of the system requirements and restrict to single and dual bus architectures. Thus there is a need in the art to overcome the above discussed limitations.

Summary of the Invention
The following presents a simplified summary of one or more embodiments in order to provide a basic understanding of such embodiments. This summary is not an extensive overview of all contemplated embodiments  and is intended to neither identify key or critical elements of all embodiments nor delineate the scope of any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.
In accordance with one aspect of the present invention is a system of flexible power distribution scheme for high availability systems  the system comprising: a plurality of power sources  an electronic device  wherein the electronic device coupled to the plurality of power sources via input lines  each input line coupling the electronic device to a respective power source and a plurality of switches includes a first switch and a second switch coupled between the electronic device and the respective power source  with both switches on  the system act as a dual bus scheme  and with one switch is on  the system act as a single bus scheme.

The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
Before undertaking the detailed description of the invention below  it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise ” as well as derivatives thereof  mean inclusion without limitation; the term “or ” is inclusive  meaning and/or; the phrases “associated with” and “associated therewith ” as well as derivatives thereof  may mean to include  be included within  interconnect with  contain  be contained within  connect to or with  couple to or with  be communicable with  cooperate with  interleave  juxtapose  be proximate to  be bound to or with  have  have a property of  or the like; and the term “controller” means any device  system or part thereof that controls at least one operation  such a device may be implemented in hardware  firmware or software  or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed  whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document  those of ordinary skill in the art should understand that in many  if not most instances  such definitions apply to prior  as well as future uses of such defined words and phrases.

Brief description of the drawings
For a more complete understanding of the present invention  and the advantages thereof  reference is now made to the following descriptions taken in conjunction with the accompanying drawings  in which:
Figure 1(a-b) shows block diagram of a single bus scheme and a dual bus scheme according to prior art.
Figure 2 shows block diagram of a scheme or a system of flexible power distribution scheme for high availability systems in accordance with one embodiment of the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example  the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.
Throughout the drawings  it should be noted that like reference numbers are used to depict the same or similar elements  features  and structures.

Detail description of the Invention
In the following description  for purposes of explanation and not limitation  specific details are set forth such as particular architectures  interfaces  techniques  etc. in order to provide a thorough understanding of the present invention. However  it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is  those skilled in the art will be able to devise various arrangements which  although not explicitly described or shown herein  embody the principles of the invention and are included within its spirit and scope. In some instances  detailed descriptions of well-known devices  circuits  and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles  aspects  and embodiments of the invention  as well as specific examples thereof  are intended to encompass both structural and functional equivalents thereof. Additionally  it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future  i.e.  any elements developed that perform the same function  regardless of structure.
Thus  for example  it will be appreciated by those skilled in the art that block diagrams herein can represent conceptual views of illustrative circuitry embodying the principles of the technology. Similarly  it will be appreciated that any flow charts  state transition diagrams  pseudo code  and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor  whether or not such computer or processor is explicitly shown.
The functions of the various elements including functional blocks labeled or described as "computer"  "processor" or "controller" may be provided through the use of dedicated hardware as well as hardware capable of executing software in the form of coded instructions stored on computer readable medium. A computer is generally understood to comprise one or more processors  and the terms computer and processor may be employed interchangeably herein. When provided by a computer or processor  the functions may be provided by a single dedicated computer or processor  by a single shared computer or processor  or by a plurality of individual computers or processors  some of which may be shared or distributed. Such functions are to be understood as being computer-implemented and thus machine-implemented. Moreover  use of the term "processor" or "controller" shall also be construed to refer to other hardware capable of performing such functions and/or executing software  and may include  without limitation  digital signal processor (DSP) hardware  reduced instruction set processor  hardware (e.g.  digital or analog) circuitry  and (where appropriate) state machines capable of performing such functions.
The present invention is directed to architecture for a redundant power supply for high availability systems which includes a number (N+1) of power supply modules having outputs connected in parallel to a single load via buses. Each of a plurality of power supply modules or converters has an associated ORing element  disposed between the output node of each module or converter and the load. The function of ORing elements is for selecting one input from two/multiple and there shall not be any interruption during the switchover. As an example embodiment this may be achieved by using two diodes when one out of two inputs is selected. The higher of the two inputs gets selected automatically and there is no interruption when one of the input fails.
The ORing elements are operable to selectively couple or decouple the power supply modules from the load  thereby effectively isolating current generated at a corresponding module from passing to the buses. The architecture of the system provides for a control circuit associated with each ORing element to control the operation of the ORing element upon detection of one or more of these conditions.
As shown in figure 2  the system includes one or more power sources or modules  an electronic device (for example a transmission system)  where the electronic device coupled to the plurality of power sources via input lines or buses  each input line or bus coupling the electronic device to a respective power source. Further  the controller is capable of determining which of the input lines or busses are in control.
The system further includes one or more switches  where the switch may include a first switch and a second switch which are coupled between the electronic device and the respective power source. The system further includes a control circuit for controlling the operation of each ORing element. The ORing elements are controlled to decouple associated power supply modules from the load upon detection of one or more of a plurality of operating conditions  each representing a failure occurring  or sub-optimal performance occurring in the system.
During an operation  the switch which is coupled to the control circuit  where both switches on  the system act as a dual bus scheme  and with one switch is on  the system act as a single bus scheme. The switch may further configured with the electronic device in order to select ratio of power to draw from the one or more buses or banks which may be further connected to power sources to meet the requirement of the load at the electronic device using the ORing element.

In an example embodiment  considering the case when the switches on different load blocks are turned on differently. With the appropriate configuration of the switches on different load blocks  the power drawn from each block can be adjusted such that approximately half the load is drawn from one of the power supply block (let’s say power supply block 1) and the other half from any other power supply block (let’s say power supply block 2) from the plurality of power supply blocks. The total number of power supplies required is:

Per Block= T/(2*P)+1
Per System= (T/(2*P)+1)*2

Where T is total power required by the system and P is the power output of a single power supply.

So by having just one power supply more than the Single Bus Scheme  the benefits of the Dual Bus Scheme are achieved. The total number of power supplies required in the system is also lower than what is required in the Dual Bus Scheme. The present invention thus provides the benefit of both the schemes without any compromise. In comparison with Dual Bus Scheme  the present invention provides more usage power for the system with the same number of power supplies.

The present invention does not require power supply capacity to be twice of the system requirement and also by having dual bus architecture there is no single point of failure while having power supply capacity that is only slightly higher than the system requirements.

As shown in figure 2 the architecture or scheme is similar to the Dual Bus architecture except for the addition of the switches in the input path in the load block. With both switches ‘ON’  the present architecture becomes equivalent to the Dual Bus Scheme and with only one switch ‘ON’ (the same one on all load blocks)  the present system is equivalent to the single bus scheme.

FIGS. 1-2 are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated  while others may be minimized. FIGS. 1-2 illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.

We Claim:

1. A system of flexible power distribution scheme for high availability systems  the system comprising:
a plurality of power sources;
an electronic device  wherein the electronic device coupled to the plurality of power sources via input lines  each input line coupling the electronic device to a respective power source; and
a plurality of switches includes a first switch and a second switch coupled between the electronic device and the respective power source  with both switches on  the system act as a dual bus scheme  and with one switch is on  the system act as a single bus scheme.

2. The system of claim 1  further comprising:
an ORing element coupled with the electronic device in order to decouple associated power supply modules from the load upon detection of one or more of a plurality of operating conditions.

3. The system of claim 1  wherein the controller is capable of determining which of the input lines or busses is in control.

4. The system of claim 1  wherein the switch is configured such that any ratio of power is drawn from the plurality of power sources to meet the requirement of the load at the electronic device.

5. The system of flexible power distribution scheme for high availability systems substantially as herein described with reference to the above mentioned description and accompanying drawings.
Dated this the 20th day of February  2012

Abstract
A system of flexible power distribution scheme for high availability systems
The present invention relates to a power supply systems and particularly to the power distribution scheme for high availability systems. In one embodiment this is accomplished by a plurality of power sources  an electronic device  wherein the electronic device coupled to the plurality of power sources via input lines  each input line coupling the electronic device to a respective power source and a plurality of switches includes a first switch and a second switch coupled between the electronic device and the respective power source  with both switches on  the system act as a dual bus scheme  and with one switch is on  the system act as a single bus scheme.
Figure 2 (for publication)