SE542435C2 - Alternative power sources for a modular power supply for starvation prevention in high-current computer power delivery systems - Google Patents

Abstract

The present invention introduces power sources alternative to AC/DC Power Bricks for a modular computer power delivery system.In the case where a plurality of computers are located close to each other, it is more practical to provide power from a Common Power Bank than from a number of individual AC/DC Power Bricks. The Common Power Bank can be fed from a DC supply, an AC supply, a generator, or a Battery Power Source. Its main distinguishing features are distribution into separated power paths and in some situations also conversion of its input power into DC power used by the computers connected to it. This has great economic, environmental, and space-saving value for internet gaming centers, offices, server farms, and other cases where multiple computers are placed in proximity to each other.Additionally, it is shown how a Battery Power Source, either as stand-alone battery/s with regulated DC output or as a battery-backed DC/DC or AC/DC power source (possibly also fed from a generator), can be used for example for provisioning of Uninterrupted Power to such a modular power delivery system, either to one or a plurality of computers or to one or a plurality of Common Power Bank/s feeding one or a plurality of computers. The Battery Power Source feeds DC-powered computers or servers, which eliminates the DC/AC conversion required in traditional AC/DC/AC Uninterruptible Power Supplies, resulting in lower losses, smaller size, lower noise, and lower cost.

Description

Alternative Power Sources for Modular Power Supply for Starvation Prevention in High-Current Computer Power DeliverySystems Technical Field The present invention relates to a modular power delivery system used for one or a plurality ofcomputer/s.

Summary of the lnvention Swedish patent application No. 1630232-5 (further referred to as "|nvention A") presents a design ofa modular power supply, which when used with a power brick forms a power delivery system thatmakes it possible to build very small and powerful gaming computers, graphical workstations, andfile servers. lnvention A is drawn from the insight that the power handling capability can be increased as much asnecessary so long as starvation (between loads) is avoided. This is achieved by soft-start switchedpower path/s separated all the way back to (or close to) the output stage / bulk capacitors of thepower brick/s or to the power conversion stage/s immediately inside the computer chassis. Each loadgets its power from a separate path.

The present invention relates to power sources alternative to the generic AC/DC power brick (PB)that is natural for lnvention A.

While one or a plurality of PBs (8) can be used to power one single computer system, it is equallypossible to power one or a plurality of computer systems from one common power bank (CPB) (18),which in its turn can be fed from a DC supply, an AC supply, a generator, or a battery power source(BPS) (19) as described below. This has great practical value for computer / server farms.

Regardless of the number of DC power sources (20) and computer systems (21), the ability to use aBPS (19) either as stand-alone battery/s with regulated DC output or as a battery-backed DC/DC orAC/DC power source (possibly also fed from a generator) (commonly referred to as anUninterruptible Power Supply (UPS)) is expected to be very useful both for individual computers/ fileservers and for CPBs (18).

Terminology and DefinitionsAll voltages are referred to by their nominal value. For example, for this application, 12 V generallymeans the range of 11.4 V to 12.6 V or 10.8 V to 13.2 V.

GAC1 through GAC5 refer to a classification of graphics adapters that is mainly relevant to the internal design of lnvention A. lt has been omitted here as it is of little importance to the power SOUFCG.

Devices PSU: General term for a power delivery system.

AC_PSU (not depicted): The traditional metal box AC/DC switching power supply that ismounted inside the computer chassis. lt comes in a variety of formats, conforming to one ofthe ATX-related standards (ATX, SFX, TFX, CFX, LFX, Flex ATX, or other). lt typically supplies3.3 V, 5 V stand-by, 5 V, 12 V, and -12 V. lt does not have a dedicated control and monitoringconnector with the required signals, so an adapter board must be used when connecting anAC_PSU to the present invention (not depicted).

DC_PSU (9): A general term for a DC/DC switching power supply fed by 6 V to 48 V (typically12 V). lt typically supplies 3.3 V, 5 V stand-by, 5 V, 12 V, and -12 V.

DC_PSU_L (9): A legacy DC_PSU that (for obvious reasons) was not designed for interactionwith the present invention. lt does not have a dedicated control and monitoring connectorwith the required signals, so an adapter board must be used when connecting a DC_PSU_L toan AO board (not depicted). lt generally provides weak power delivery to the 12 V rails.DC_PSU_M (9): A DC_PSU that was designed for interaction with the present invention. lt hasa dedicated control and monitoring connector with the required signals. lt provides strongpower delivery to the 12 V rails but in certain use cases insufficient for very power hungrygraphics adapter(s) or multiple hard drives.

PB (8): An external AC/DC switching power brick that delivers DC voltage between 6 V and 48V (typically 12 V).

AO: Add-On function with a remote-controllable soft-start switch circuit that listens to andtransmits ”power good"-information from and to the entire power delivery system. The AOfunction supplies power to a computer component, typically a graphics adapter or one ormore hard drives. The AO function might be a separate board or an integral part of a unifiedpower delivery system. The AO board typically contains an additional pass-through of powerto the DC_PSU, which enables one standardized punch-out in the computer chassis. Unlessexplicitly expressed otherwise, the term AO stands for the soft-start switch part of the board- not the pass-through part.

CPB: A Common Power Bank (18) is a system that provides suitable DC power to one or aplurality of computer systems. lt is powered from a DC supply, an AC supply, a BPS (19), or agenerator power source.

BPS: A Battery Power Source (19) is a system that provides DC power from a battery/s or abattery-backed DC/DC or AC/DC power source. The BPS power is provided to lnvention A to a CPB (18).

Brief Description of the Drawings Components1. Input stage with connector(s) for power to soft-start switch (2), optionally including DC/DCconverter(s)2. Soft-start switch, including monitoring sub-circuits such as Over-Voltage Protection (OVP),Under-Voltage Protection (UVP), Over-Current Protection (OCP), and possibly others 3. I/O connector and soft-start switch controller 4. Output connector(s) to graphics adapter (10), 12 V 5. Input stage with connector for power to DC_PSU (9), optionally including a DC/DC converter6. Output connector to DC_PSU (9), 12 V 7. Power ground connection between DC_PSU (9) and graphics adapter (10) power paths 8. AC/DC power brick with one or more sets of cabling supplying a fixed 6 - 48 V (typically 12 V)9. DC_PSU in the form of a stand-alone device 10. Graphics adapter 11. DC/DC converter for 6 - 48 V input into 12 V (typically multiphase step-down) 12. DC_PSU (9) integrated on a common power delivery board 13. Part of a DC_PSU (9) integrated on a common power delivery board 14. Output connector for connection to motherboard 20- or 24-pin ATX connector 15. Output connector for connection to motherboard 12 V connector 16. Motherboard 17. AO board (dashed outline) 18. CPB, Common Power Bank, optionally with an additional input for power from a generator19. BPS, Battery Power Source, optionally with an additional input for power from a generator20. DC power source (PB, CPB, or BPS in any combination) with one or more sets of cabling supplying a fixed 6 - 48 V (typically 12 V)21 Computer systemConnectionsA. DC input from PB (8) to DC_PSU (9) supplying a fixed 6 - 48 V (typically 12 V)B. DC input from PB (8) to soft-start switched (2) load supplying a fixed 6 - 48 V (typically 12 V)via one or more separate cablings.C. Monitoring and control signals in and outD. DC output to motherboard 20- or 24-pin ATX connector (typically 5 V standby, 3.3 V, 5 V, 12V, and -12 V) E. DC output to motherboard 12 V connector F. DC output to DC_PSU (9), typically 12 V G. DC output to graphics adapter (10) (12 V) or hard drives (any combination of 3.3 V, 5 V, and 12 v)H. AC Input to PB (8), typically AC in the range of 90 to 265 V and 47 to 63 Hz Input/s to DC power source (20), e.g. AC in the range of 90 to 265 V and 47 to 63 Hz, DC (e.g.from a PB (8) or a higher-voltage rail), or AC or DC from a generator.

Figures Fig 1. DC_PSU_M (9) using an AO board (17) for the pass-through function (A to F) only. Thisis an example of an entry-level configuration for an lnvention A GAC1 through GAC3 gamingcomputer that is prepared for easy upgrade to support a more powerful graphics adapter(fig. 2 or 3). With a DC_PSU_L (9) this supports GAC1 and some GAC2 graphics adapters.

Fig 2. DC_PSU (9) using an AO board (17) both for pass-through (A to F) and for soft-startswitching (2) of power to an lnvention A GAC3 through GAC5 graphics adapter. ln thisexample it is powered by one common PB (8) with two sets of cabling (GAC3 or GAC4) orthree sets (GAC5).

Fig 3. DC_PSU (9) using an AO board (17) both for pass-through (A to F) and for soft-startswitching (2) of power to an lnvention A GAC3 through GAC5 graphics adapter. ln thisexample it is powered by two separate PBs (8.1 and 8.2) with one set (DC_PSU (9)) (F) andone or two sets (graphics adapter (10)) (G) of cabling each. This is an example of re-use ofpre-existing equipment.

Fig 4. DC_PSU (9) using two AO boards (17.1 and 17.2), one of which for pass-through (A toF) and both for soft-start switching (2) of power to one lnvention A GAC3 through GAC5graphics adapter each, in Scalable Link Interface (SLI) or Cross-Fire configuration. ln thisexample it is powered by one common PB (8) with three sets of cabling (GAC3 or GAC4) orfive sets (GAC5).

Fig 5. DC_PSU (9) using two AO boards (17.1 and 17.2), one of which for pass-through (A toF) and both for soft-start switching (2) of power to one high-end graphics adapter (10) each,in Scalable Link Interface (SLI) or Cross-Fire configuration. ln this case it is powered by threeseparate PBs (8.1, 8.2, and 8.3) with one or two sets of cabling each. This is an example ofre-use of pre-existing equipment, possibly an upgrade from fig. 3.

Fig 6. Example of alternative solution with DC/DC converter (11) that generates 12 V forgraphics adapter(s) (10.1 and 10.2), motherboard 12 V connector (15), and motherboard 20-or 24-pin ATX connector (14). A second DC/DC converter block (13) generates the rest of theDC_PSU voltages (5 V stand-by, 5 V, 3.3 V, and -12 V). lt only incorporates soft-start switching(2) of the 5 V rail. The 12 V output is inherently soft-started by the DC/DC converter (as is the3.3 V output). lt is powered by one single PB (8) at 24 to 48 V. lt is not in compliance with the240 VA limitation. lt could be further equipped with Over-Current Protection (OCP) on eachoutput rail, each signaling ”power good” to the entire power delivery system. This would bein compliance with the 240 VA limitation.

Fig 7. Example of a modification to fig. 6 that complies with the 240 VA limitation. There is asoft-start switch circuit (2.1 and 3.1, & 2.2 and 3.2) on every 12 V output (4.1 and 4.2).Fig 8. Example of a modification to fig. 6 in which the common 12 V DC/DC converter has been broken up into several ones (11), each limited to 240 VA and inherently soft-started.

Fig 9. The equivalent to fig. 2 with the nomenclature used for the present invention.

Fig 10. Example of the equivalent to fig. 4 with an additional BPS (19), in this case fed fromAC.

Fig 11. Example of feeding a plurality of computer systems from a CPB (18), here fed from AC.

Fig 12. Example of adding a BPS (19) to fig. 11 and feeding it from both AC and a generator.

Fig 13. Example of a plurality of CPBs (18) fed from AC or a 48 V DC rail.

Fig 14. Example of a plurality of CPBs (18) running on 48 V DC fed by an additional BPS (19)fed from both AC and a generator.

Background InformationThere are four main consumers of power in today's computer: 1. Motherboard: 3.3 V, 5 V stand-by, 5 V, 12 V, and -12 V fed into the 20- or 24-pin powerconnector on the motherboard 2. Motherboard: 12 V fed into a 4- or 8-pin power connector on the motherboard. This inputoften supplies power to the CPU and the PCI Express bus. 3. Graphics adapter: A gaming PC or graphics workstation needs a significant amount of 12 Vpower fed into one or a few 6- or 8-pin power connectors on the graphics adapter. 4. Hard drives and other peripherals: A suitable combination of 3.3 V, 5 V, and 12 V fed into oneor more hard drives. For a file server with mechanical drives, a great deal of power is neededfor the 12 V rail, especially at spin-up.

For the range of computers most relevant to this invention, the graphics adapter is the mainconsumer, followed by the motherboard CPU input. For file servers, the main consumer is the set ofmechanical hard drives that in particular require much current on the 12 V rail when spinning up.

The power delivery system must meet the following requirements: I. Facilitate synchronized turn-on and turn-off. ll. Meet rise-time and rise-order requirements for the rails.|||. Monitor the quality of the power delivered on every rail.IV. Provide emergency shutdown of the entire system in case of a failure condition.V. Provide power to either all rails or no rails (except for the 5 V stand-by).

The equipment might break if this is not enforced.

IEC 60950-1:2005 defines hazardous energy level as ”available power level of 240 VA or more, havinga duration of 60 s or more, or a stored energy level of 20J or more (for example, from one or morecapacitors), at a potential of 2 V or more” (definition 1.2.8.10). lt is thus desirable (although notabsolutely necessary) to design for less than 240 VA, which in this document is referred to as ”the240 VA limitation".

The ATX and derived standards specify two signals for communication between the motherboard andthe PSU, found on the 20- or 24-pin motherboard power connector: 0 PS_ON#: To start and run the computer, the motherboard shorts this signal to ground, whichcauses the PSU to turn on the 3.3 V, 5 V, 12 V, and -12 V rails. (5 V stand-by is always on.)When this signal is connected to 5 V stand-by or open-circuited (thereby left pulled-up to 5 Vstand-by), the PSU must turn off all rails except 5 V stand-by. 0 PWR_OK: The PSU stops shorting this signal to ground (thereby letting it be pulled up to 5 Vstand-by) when the power is good on all rails. This tells the motherboard that it is safe toboot up and maintain normal operation. The PSU shorts this signal to ground in case of afailure condition (i.e. power is no longer good) which causes the motherboard to stopoperating. lf PWR_OK goes low while PS_ON# is low, this is an alert of a failure condition to the rest ofthe modular power delivery system.

Problem Description Motivation for Invention AThere are currently two types of computer power supplies; the traditional AC_PSU metal box (notdepicted) and the legacy DC_PSU (DC_PSU_L) (9) connected to an external power brick (PB) (8): The AC_PSU is in widespread use and can be bought with sufficient power handling capability, evenfor very power-hungry computers. A drawback is that it is not upgradable - it's an atomic unit, so ifyou need a more powerful one, you must buy a new one to replace the old. lt comes in a variety ofshapes in accordance with one of the ATX-related standards, all of which are mounted inside thecomputer chassis, typically have a more or less noisy cooling fan, and limit the minimum size anddesign freedom of the computer chassis and the other components inside the box.

Commercially available AC_PSUs tend to require a significantly higher total power rating than what isactually needed by the computer system. This is a question of power distribution over the differentpower rails (too much made available to the 3.3 V and 5 V rails) and what seems to be an inability tosustain power delivery at great load current changes on the 12 V rai|(s), especially at start-up. Tosome extent this need for over-dimensioning of AC_PSU power places the average load at a pointwhere the efficiency is less than optimal, causing unnecessary losses.

The DC_PSU_L (9) currently on the market is a step forward in the sense that most of the heatgeneration is moved to the external PB (8) and that the part inside the computer chassis is muchsmaller. Having only the relatively small DC_PSU_L (9) inside the chassis gives greater freedom whenplanning the placement (and available size) of the computer components. lt is however too weak forgaming computers and file servers.

By implementing a series of design improvements, it is possible to increase the DC_PSU_L's (9)capability so that it can be used for at least 6-disk file servers and Invention A GAC3 gamingcomputers. Some of these improvements consist of placing bulk capacitors within the DC_PSU (9) (inaddition to the ones in the DC power source (20) and soft-start switching the 12 V rail (as opposed tothe commonly used instantaneous high-side turn-on of a P-channel MOSFET transistor which causesan inrush current that might force the DC power source (20) into short-circuit protection). Adding afew additional improvements not further mentioned here, we have a device referred to as aDC_PSU_M (9).

This improved type of solution still suffers from a few natural limitations, most importantly the factthat the DC power source's (20) feedback loop can only tolerate a certain (but unknown) amount ofexternal bulk capacitance before it becomes unstable and unfit to use. Having only one power pathfrom which all loads (10) share the same cabling and external bulk capacitance means that at somepoint the different loads will drain the DC_PSU_M's (9) energy storage and starve each other out.Even the small resistance and inductance in the cabling is too much of a hindrance to the loadtransients' sourcing current from the DC power source's (20) bulk capacitors / output stage ratherthan starving the other loads (10).

Motivation for the present invention lnvention A mainly relates to power delivery to a single computer system (21). However, there are anumber of situations in which you would want a common DC power source (20) for a plurality ofcomputer systems or for protection from power failure.

A set of gaming computers at an internet gaming café would be better fed by a CPB (18) than anumber of individual PBs (8). The same is true for computer/ server farms that in many cases arealready fed from a common Uninterruptible Power Supply (UPS) or BPS (19), so sharing a commonpower source is close at hand. Fewer components, lower cost, and smaller size are some of thebenefits.

Traditional UPS devices typically convert energy stored in batteries into mains-level AC thattraditional PSUs are running on. With invention A, this DC to AC conversion is an unnecessary stepthat can be eliminated, which results in lower losses, smaller size, lower noise, and lower cost.

Solutions Enabled by lnvention A and the Present lnventionThere are two possible types of solution to this problem drawn from the insight that the powerhandling capability can be increased as much as necessary so long as starvation is avoided: 0 Soft-start switch (2) controlled power paths separated all the way back to (or close to) theoutput stage/ bulk capacitors of the DC power source (20)0 Power conversion stage(s) (11) immediately inside the computer chassis These two approaches have different implications and properties. ln both cases the main power isconsumed on the 12 V rails into the different loads (including the 12 V rail leaving the DC_PSU (9)itself). The anticipated common case is to supply one or more graphics adapters (10, or 10.1 and10.2) in this way, but the same principle also applies to file servers with more hard drives than theDC_PSU_M (9) can support. lnvention A has an AC/DC Power Brick (PB) (8) for a DC power source (20) as this makes most sensefor its intended use case. The present invention adds alternative power sources (Common PowerBank (CPB) (18) and/or a Battery Power Source (BPS) (19)).

While one or a plurality of PBs (8) can be used to power one single computer system, it is equallypossible to power one or a plurality of computer systems (21) from one common power bank (CPB)(18), which in its turn can be fed from a DC supply, an AC supply, a generator, or a battery powersource (BPS) (19) as described below. This has great practical value for computer/ server farms.

Regardless of the number of power sources and computer systems, the ability to use a BPS (19)either as stand-alone battery/s with regulated DC output or as a battery-backed DC/DC or AC/DCpower source (possibly also fed from a generator) (commonly referred to as an UninterruptiblePower Supply (UPS)) is expected to be very useful both for individual computers/ file servers and forCPBs (19). Please see Brief Description of the Drawings for additional information.

Separated Soft-Start Switch Controlled Power PathsEach load gets its power from a path separated all the way back to (or close to) the output stage/bulk capacitors of the DC power source (20), controlled by its own soft-start switch (2).

This is a truly modular approach with natural upgrade paths.

Fig. 1 through 5 illustrate various combinations and upgrade paths, starting with a system that has anlnvention A GAC1 through GAC3 graphics adapter (fig. 1) so the AO board (17) is only used for pass-through to the DC_PSU (9). When the user wants to upgrade to a more powerful graphics adapter,the actual AO board (17) is taken into service (the soft-start switch part (2 and 3)). Fig. 2 shows thecase where one DC power source (20) (in this case a PB (8)) supplies both DC_PSU (9) and AO board(17) via separate cablings, while fig. 3 shows the pre-existing PB (8.1) supplying the DC_PSU (9) andan additional PB (8.2) supplying the AO board (17).

Fig. 4 and 5 illustrate the next upgrade step, to using two graphics adapters (10.1 and 10.2) inScalable Link Interface (SLI) or Cross-Fire configuration. This requires additional AO board(s) (17.1and 17.2) and either more PB cabling or more PBs. This approach is scalable far beyond the use oftwo graphics adapters (10.1 and 10.2).

Fig 9. shows the equivalent to fig. 2 with the nomenclature used for the present invention.

Fig 10. depicts an example of the equivalent to fig. 4 with an additional BPS (19), in this examplepowered from AC. This could for example be a battery-backed desktop/Workstation/gamingcomputer/server that must be powered down gracefully in case of a power failure. The combinationof lnvention A and a BPS (19) enables the smallest, coolest, most energy-efficient, and most quietcomputer with a dedicated UPS.

Fig 11. lllustrates an example of feeding a plurality of computer systems from a CPB (18), in thisexample powered from AC. The CPB could in this case be a device designed to be a CPB or a verypowerful PB (8). lt could for example be used for a set of gaming computers at an internet/gamingcafé, where small size but not battery backup is needed. ln fig 12. a BPS (19) fed from both AC and a generator has been added to fig 11. This is an example ofa small-scale computer / server farm with battery backup.

Fig 13. Is an example of a larger-scale computer/ server farm with a plurality of CPBs (18) fed fromAC or e.g. a 48 V DC rail. The individual CPBs would probably be interconnected in some fashion forcontrol and monitoring of operation and possibly also remote start of the individual computersystems.

Lastly, Fig 14. as an example presents an extension to fig. 13 in which a plurality of CPBs (18) runningon e.g. 48 V DC are fed by an additional BPS (19) supplied from both AC and a generator.

Like in lnvention A, it doesn't matter if power source connections (A) or (B) to a computer systemcome from a common or different DC power sources.

Please note that the purpose of separation between loads is to prevent starvation between loads insituations when it is easier to drain the neighbor/s than to draw energy from the power sourceshared by these particular loads. Strictly speaking, the connections don't have to be perfectly V- shaped. ln fact more or less every practical implementation of lnvention A's "Separate power pathsall the way back to the output stage/ bulk capacitors") is to a certain degree Y-shaped albeit with acomparatively short common stem and very long individual branches.

A group of computer systems connected to a CPB (18) or a BPS (19) are likely to have longer powercables, which makes slightly longer common stems possible without risk of starvation (although theindividual branches must still be sufficiently longer in comparison). Hence the revised wording "Soft-start switch (2) controlled power paths separated all the way back to (or close to) the output stage/bulk capacitors of the DC power source (20)".The power paths through the AO board (17) can consistof more than one (typically no more than two) cablings and connectors in parallel, although theillustrations only depict one instance. The reason for this optional parallelization is presented below.

All connectors experience a temperature rise at the point where the male and female terminalsattach. Also, the wires themselves heat up slightly. lt is advisable to use thick high-quality wires andconnector terminals rated for high current. The optional parallelization could be used to reducepower loss and temperature rise in use cases where e.g. a more powerful PB (8) was bought thanwhat was initially needed. lt is essential that you only parallelize cablings from one DC power source(20) for each power path. Connecting multiple DC power sources (20) to the same power path couldbreak the equipment (in particular the DC power source itself) or result in erratic behavior.

The 240 VA limitation is probably less important for computer systems in more industrial orprofessional installations (such as a server farm), as these are constructed for a specific function in amore controlled environment.

Please note that with much smaller computer chassis and cleverly positioned AO board(s) (17, or17.1 and 17.2), the cables inside the box are much shorter than the ones used with an AC_PSU (notdepicted) in a traditional computer chassis. A great fraction of theses cable and connector lossesalready occur in AC_PSU computers.

The combined voltage drop in the power path should be compensated for by supplying not 12.0 Vbut some 12.3 V. The ATX standard states 12 V +/- 5% but allows up +/- 10% at heavy load. So long asthe 12 V lines always stay between 10.8 V and 13.2 V we're safe.

Depending on the type of installation, each cabling output from the DC power source (20) might havea 240 VA Over-Current Protection (OCP), which could be as simple as a fuse. As the AO board (17)detects loss of input power and incorporates its own sophisticated OCP, the 240 VA limitation is met. ln order to establish and maintain a standard that is easily understood by the user and as far aspossible avoids user errors, a consistent use of 12 V DC power sources (20) is advised for connectionsto the computer systems (21). lt is quite possible to implement a DC/DC converter at the AO board (17) power input(s) and maintainthe modular approach, but if the point is to reuse PBs (8) (e.g. from retired laptop computers) thatsupply another voltage (typically 16 V to 21 V), the number of connector types, polarizations, andpotential user errors makes you think twice.

This approach can be used to augment power to both DC_PSU (9) and AC_PSU (not depicted). TheDC_PSU_M (9) is designed for this modular concept and the DC_PSU_L (9) and AC_PSU can be used with an additional adapter board (not depicted) that provide the necessary signals (presentedbelow).

Power Conversion Stage(s) Immediately Inside the Computer ChassisThis approach moves the effective output stage/ bulk capacitors closer to the loads, as illustrated infig. 6 through 8.

While this solution can be used with 12 V DC power sources (20), it makes most sense to utilize ahigher input voltage (24 V or up to 48 V) into a main DC/DC step-down converter (11) that outputs 12V, eliminating or reducing the need for multiple sets of cabling. At some point you reach a voltagelevel that could be dangerous to humans and pets if they are exposed to open conduits. lf you want to take advantage of the possibility to use only one input connector, this more or lessleaves you with a monolithic design of a series of products with different power rating. There is noclear upgrade path.

The DC/DC-converter incurs an additional cost, needs considerable space, and generates so muchheat that it must be cooled by a fan. For high currents, a multi-phase design is more or less the onlyoption, but it has inherently high low-load losses (unless EMI-noisy pulse-skipping or burst modeoperation is used).

Fig. 6 and 7 show the use of one common very high-current DC/DC converter at the input, generating12 V at up to some 50 A. ln fig. 6 the DC/DC converter's inherent soft-start design means that theseparate soft-start switches (2) are not necessary for it to function. The problem is that this is inviolation of the 240 VA limitation. You might need to add Over-Current Protection (OCP) on each loadconnector with monitoring of the output voltage and reporting these statuses to the whole powerdelivery system (not depicted). This brings you very close to fig. 7 in which the (monitored) soft-startswitches (2.1 and 3.1, & 2.2 and 3.2) are brought back. ln fig. 8 each output is supplied from its own soft-started DC/DC converter limited to 240 VA.Multiple DC/DC converters cause even higher conversion losses, need even more space, and costeven more money.

The DC power source (20) would need roughly the same number of OCP functions as in the otherapproach (per computer system), although protection should be provided per wire rather than perconnector. As before, the individual DC power source (20) OCP function could be a simple fuse.

Control, Monitoring, and Safety Circuits A very important detail is the absolute need to incorporate synchronized start-up of all rails, adheringto rise-time and rise-order requirements. lt is also necessary to monitor the quality of the power(voltage and current) delivered on each rail, with synchronized emergency shutdown of all rails incase of a failure anywhere in the power delivery system and prevention of start-up in the case whennot all power path inputs are energized (A and B). Part of these safety measures are incorporated inthe PSU, some in the motherboard, and some in the AO board (17). Each part of the power deliverysystem is responsible for monitoring its own power path, terminating power delivery in case itdetects a failure, receiving the status from the other parts of the power delivery system, andtransmitting its own status to the other parts, possibly also comprising a shutdown backup circuit asdiscussed below. ln some implementations it is beneficial to use the following two types of active-high signals and twotypes of active-low signals with pull-up resistors to logic high (typically 5 V stand-by): 0 PS_ON#: The ATX motherboard signals power on (low) or off (high or high-Z) to the PSU or aderivate thereof. At least one PSU supervisor integrated circuit (TPS3510) outputs a controlsignal (FPO#) that for the present application could be used to perform the same function asPS_ON#. FPO# is an example of a signal derived from PS_ON#. 0 ENABLE: The inverted derivative of the PS_ON# control signal from the motherboard, suchthat it can be forced to ground in order to terminate ongoing operation (such as start-up andreboot prevention). lt thus provides a means for emergency shutdown of all power delivery. 0 PS_ON_PROTECTED#: The inverted ENABLE signal passed on to the PSU from the adapterboard. 0 PWR_OK: The ATX status indicator. lt is pulled low by any part of the power delivery systemwhen one of its rails fails to provide appropriate voltage and current. The motherboardreacts by terminating operation and releasing PS_ON#.

The AC_PSU (not depicted) and the DC_PSU_L (9) must use an adapter board connected between themotherboard 20- or 24-pin connector and the PSU connector. lt inverts PS_ON# into ENABLE, invertsENABLE into PS_ON_PROTECTED#, and brings out ENABLE, PWR_OK, and optionally PS_ON# signalsto the control and monitoring connector. The DC_PSU_M (9) is designed so that these three signalsand connector are integrated on the DC_PSU_M (9) itself, which means that an adapter board is notnecessary.

Start-Up Prevention By implementing a circuit that acts as a normally closed relay, it is possible to short ENABLE andPWR_OK to ground when the power input is not energized and to release these signals (to be pulledup) when the power input is energized. Alternatively, a P-channel depletion mode MOSFET performsthe same function.

Equipment Protection in Case of Invalid Input Power Disconnection A power failure mode that is unique to the modular design is the case of a DC power input connectorbeing disconnected when the computer is running. The start-up prevention protection covers thiscase by abruptly turning off power delivery (by shorting ENABLE to ground), which should besufficient for preventing equipment from breaking.

Power Delivery Failure Signaling and Emergency Shutdown The PWR_OK signal is pulled low by any part of the power delivery system in case of a failure duringnormal on-going operation. This is detected by the motherboard that immediately releases PS_ON#,which turns off power delivery. This provides a form of inherent emergency shutdown. lt is possible but perhaps not necessary to implement a backup circuit in the AO board (17) that pu||sENABLE low if the AO board (17) detects PWR_OK going low while PS_ON# is held low by themotherboard (i.e. the moment just before the motherboard releases PS_ON#). ln more detail: 1. The motherboard pu||s PS_ON# low in order to start-up the computer. PWR_OK is initiallyheld low by the power delivery system.2. The power delivery system tries to start up all rails.After a certain short period the safety feature checks the outcome:a. lf PWR_OK is still pulled low it means that there is a power delivery system failure.ENABLE is pulled low until the motherboard releases PS_ON#.b. lf PWR_OK has gone high, the safety feature waits for PWR_OK going low. lf thishappens while PS_ON# is held low by the motherboard, ENABLE is pulled low untilthe motherboard releases PS_ON#.

So far it's simple. The thing is that many motherboards automatically retry indefinitely, which couldbe a problem in case of a hardware malfunction. The difficult question is whether an additionalsafety feature should be implemented; reboot prevention.

Reboot Prevention Depending on what caused PWR_OK to be pulled low, a reboot can either be the most practical tothe user or completely unwanted. lf we had an Under-Voltage Condition (UVC) it could be becausewe were e.g. using a DC power source (20) of insufficient power rating, tried over-clocking tooaggressively, or experienced a short AC line drop. ln these cases we want the computer to rebootautomatically. On the other hand, if we had any type of error due to a breakdown in a component inthe computer or in the power delivery system, we would want the entire power delivery system toremain shut off. As far as the inventor knows, AC_PSUs don't generally keep track of what wentwrong, so they typically let the motherboard decide whether to reboot, which it seems to generallydo.

The additional safety feature is an optional latch that keeps ENABLE low after the backup circuit hastriggered. |t's necessary to power cycle the input power of the part of the power delivery system thatis holding the latch in order to make it release it. This is a new type of safety feature for computerpower supplies.

Benefits lnvention A makes it possible to build very small Q powerful gaming computers, graphicalworkstations, and file servers. The AC_PSU is no longer the only option, which frees valuable spaceinside the computer chassis and gives greater layout freedom in the chassis. lt is easy to buildstandard-component computers that are 33 % to 50 % smaller by using the current invention. Thisreduces the computer to a size at which it is portable; a powerful gaming computer that is smallenough to put in the hand luggage. As a further example, it can be placed by the living-room TV forsocial Virtual Reality (VR) gaming, in addition to all the present areas of use.

The modular concept of lnvention A makes it possible for the owner to upgrade from using only aDC_PSU (9) and a PB (8) without an AO board (17) to using the same DC_PSU (9) and PB (8) togetherwith one or more AO boards (17, or 17.1 and 17.2) and PBs (8, or 8.1 and 8.2), simply addingequipment and not throwing away the pre-existing equipment. This is of great economic andenvironmental value. lt is even possible to augment the power handling capability of an AC_PSU inthis way.

The present invention adds alternative DC power sources (Common Power Bank (CPB) (18) and/or aBattery Power Source (BPS) (19)), to the Power Brick (PB) (8) of lnvention A, which has great practicalvalue for computer/ server farms and / or computer systems that must be shutdown gracefully incase of a power failure.

Prior Art 0 US7539023B2 (Monolithic plug-in power supply): This expired patent describes and onlyconcerns the type of device referred to as DC_PSU_L in this text. 0 US8878390B2/ US9223371B2 (Adaptor for adding a second power supply unit to a computersystem): This patent concerns an adaptor board that enables plug-and-play parallelization oftwo or more individual and separate AC_PSU ATX power supplies through a daisy-chainedseries of adaptor boards. Each link in this chain contains one adaptor board and an additionalAC_PSU. The adaptor board consists of a 4-pin legacy peripherals power connector to theAC_PSU in the previous link, a relay, and a 20- or 24-pin power connector for on/off controlof the current link's additional AC_PSU. When the previous link powers up, it energizes therelay that pulls PS_ON# low and thereby powers up the current link's AC_PSU.

This patent is based on the use of two or more full-blown individual AC_PSUs. There is thusexcellent separation between the rails, but rise-time and rise-order requirements are notmet (or even considered). There is no way for a down-link AC_PSU to signal an errorcondition to the up-link AC_PSU(s), which means that an error condition might break theequipment due to some components being energized while others are not.

For these reasons, this type of configuration can only be used for peripherals that can besafely energized in solitude. Hard drives are one such example, but they are the only type ofpower-hungry peripherals for which one low-power AC_PSU might not be sufficient when agreat number (>6) of hard drives are used. There is no PC computer chassis with room formore than one non-redundant AC_PSU on the market. lt is not clear what problem this priorart is actually attempting to solve, but it can only be used for a problem that doesn't reallyexist. lt will most likely never be incarnated as a usable product.

The conceptual design of this patent is essentially different compared to the add-on boarddescribed in the present application. While figures 4 and 5 in the present document supportparallelization of multiple add-on boards, they are not daisy-chained but truly parallel on onecommon control and monitoring bus. The solution in the present document can safely beused for graphics adapters and CPU power as it incorporates all the necessary safetymechanisms and timing requirements. ln the present application the power is routedthrough and switched inside the add-on board, while the prior art is switching only thecontrol signal in the adaptor. Finally, the present document only adds the AC/DC powerconversion to the voltage rails that are actually needed. The present document enables newmarket segments of smaller and quieter gaming computers, graphics workstations, and fileservers. The prior art patent causes a need for a bigger PC chassis.

Other PublicationsATX12V Power Supply Design Guide, v2.31 (Power Supply Design Guide for Desktop Platform FormFactors, v1.2): http://www.formfactors.org/developer/specs/Power_Supply_Design_Guide_Desktop_Platform_Rev_1_2.pdf http://std.iec.ch/terms/terms.nsf/welcome?OpenForm (search by term "hazardous energy level")

Claims (22)

Claims

1. A soft-start switch circuit (2 and 3), working in conjunction with a pre-existing computerpower delivery system or being an integral part of such a system, for power delivery to atleast one component of a computer, comprising at least one separated power supply path;which is separated all the way back to, or close to, an output stage/ bulk capacitors of a DCpower source (20), wherein each component gets its power from a separated power supplypath; and wherein each part of the computer power delivery system is responsible formonitoring its own power path, receiving the status from other parts of the computer powerdelivery system, and transmitting its own status to other parts; wherein the soft-start switch circuit (2 and 3) is configured to: receive command/s êx-aleæ--ëï-š--to activate or deactivate power delivery to the at least one computer component (e~.-g;\;=--10); output a voltage ramped up to a fixed level to the at least one computer component(\<=f,\§§-.-10) on the at least one separated power supply path (B to G) when the activation command is received-šaiêeæ-iflš-ls; discontinue power delivery when the deactivation command is received-šaiêeæ-iflš-fs; and receive and transmit a signal-š-*všæs-šëšå stating whether an adequate voltage and current level is received by the at least one computer component (e.-.,\§§-.-10).

2. The soft-start switch circuit (2 and 3) according to claim 1, wherein the DC power source (20)comprises a battery power source (19), configured to supply one to a plurality of computer systems.

3. The soft-start switch circuit (2 and 3) according to claim 1, wherein the DC power source (20)comprises a common power bank (20), configured to supply one to a plurality of computer systems.

4. The soft-start switch circuit (2 and 3) according to any of claims 1-3, wherein the DC power source (20) is based on Direct Current.

5. The soft-start switch circuit (2 and 3) according to any of claims 1-3, wherein the DC power source (20) is based on Alternating Current.

6. The soft-start switch circuit (2 and 3) according to any of claims 1-5, further configured todiscontinue power delivery when it detects a voltage or current delivery failure in its powersupply path (B to G) and transmit this information to the other parts of the power delivery system-(æaifiss-êš).

7. The soft-start switch circuit (2 and 3) according to any of claims 1-6, wherein the outputvoltage is ramped up to 12 Volt when the power delivery is provided to at least one graphicsadapter (10); and ramped up to any combination of 3.3 Volt, 5 Volt, and 12 Volt when the power delivery is provided to at least one hard drive.

8. The soft-start switch circuit (2 and 3) according to any of claims 1-7, further comprising any combination of protection circuits for: start-up prevention by prohibiting the activation command when not all power inputs (A and B) are energized; invalid power disconnection protection by enforcing the deactivation command when one power input loses power during on-going operation (A or B); emergency shutdown by enforcing the deactivation command when a signal stating power delivery failure is received-(ssšaä-ilšš; and reboot prevention by latching the enforced deactivation command when a signalstating power delivery failure is received-{f-s=~§\=æ-álš§~, and by releasing this latch when the input power is cycled.

9. The soft-start switch circuit (2 and 3) according to any of claims 1-8, wherein: the activation command is implemented as an active-high signal bus (C) with pull-up to logic high, where activation is effectuated when no part of the power delivery system is forcing this signal low, further referred to as ENABLE; the deactivation command is implemented as the ENABLE signal being forced low; and prohibiting the activation command and enforcing the deactivation command both mean that the ENABLE signal is being forced low.

10. An add-on board (17) comprising a soft-start switch circuit (2 and 3) according to any of claims 1-9.

11. The use of an adapter board, with which a DC_PSU_L or an AC_PSU can be used with at leastone soft-start switch circuit (2 and 3) according to any of claims 1-9 or at least one add-onboard (17) according to claim 10; the adapter board connected between a motherboard 20-or 24-pin connector and a PSU connector, inverting PS_ON# from the motherboard (16) intoan active-high pulled-up activation signal further referred to as ENABLE, inverting the ENABLEsignal into a signal further referred to as PS_ON_PROTECTED# passed on to the PSU from theadapter board, and bringing out ENABLE, PWR_OK, and optionally PS_ON# signals to a control and monitoring connector.

12. An adapter board, with which a DC_PSU_L or an AC_PSU can be used with at least one soft-start switch circuit (2 and 3) according to any of claims 1-9 or at least one add-on board (17)according to claim 10; the adapter board connected between a motherboard 20- or 24-pinconnector and a PSU connector, inverting PS_ON# from the motherboard (16) into an active-high pulled-up activation signal further referred to as ENABLE, inverting the ENABLE signalinto a signal further referred to as PS_ON_PROTECTED# passed on to the PSU from theadapter board, and bringing out ENABLE, PWR_OK, and optionally PS_ON# signals to a control and monitoring connector.

13. A computer power delivery system comprising at least one soft-start switch circuit (2 and 3) according to any of claims 1-9.

14. A method by which a soft-start switch circuit (2 and 3), working in conjunction with a pre-existing computer power delivery system or being an integral part of such a system, is usedfor power delivery to at least one component (eagw-ÅO) of a computer, comprising at least oneseparated power supply path, which is separated all the way back to, or close to, the outputstage / bulk capacitors of a DC power source (20), wherein each component gets its power from a separated power supply path; and wherein each part of the computer power delivery

15.

16.

17.

18.

19. system is responsible for monitoring its own power path, receiving the status from otherparts of the computer power delivery system, and transmitting its own status to other parts; which method comprises: receiving command/s-å-afaëæ-éšl-fs- to activate or deactivate power delivery to the at least one computer component (e §f-10); outputting a voltage ramped up to a fixed level to the at least one computercomponent (\<=_~.-g;\;=--10) on the at least one separated power supply path (B to G) when the activation command is received--š-tešeawiši-š; discontinuing power delivery when the deactivation command is received-ßàšeæ-ëš-fs; and receiving and transmitting a signal--ävšæs-éši-š stating whether an adequate voltage and current level is received by the at least one computer component (e.\¿§-.-~10). The method according to claim 14, wherein the DC power source (20) comprises a battery power source (19), configured to supply one to a plurality of computer systems. The method according to claim 14, wherein the DC power source (20) comprises a common power bank (18), configured to supply one to a plurality of computer systems. The method according to any of claims 14-16, wherein the DC power source (20) is based on Direct Current. The method according to any of claims 14-16, wherein the DC power- source (20) is based on Alternating Current. The method according to any of claims 14-18, further comprising: discontinuing power delivery when detecting a voltage or current delivery failure in its power supply path (B to G) and transmitting this information to the other parts of the power delivery system-(æfèas-álš).

20. The method according to any of claims 14-19, further comprising any combination of the following measures of protection: providing start-up prevention by prohibition of the activation command when not all power inputs are energized; providing invalid power disconnection protection by enforcement of the deactivationcommand---<§=.~4e>\---ê;š§~ when one power input (A or B) loses power during on-going operation; providing emergency shutdown by enforcement of the deactivation command when a signal stating power delivery failure is received-š-\.-«É~@>-<<š;§-; and providing reboot prevention by latching the enforced deactivation command when asignal stating power delivery failure is received--š-“tæšfla-éši-š, and by releasing this latch when the input power is cycled.

21. The method according to any of claims 14-20, further comprising: inverting an ATX standard control signal PS_ON# from a motherboard (16) into anactive-high pulled-up activation signal further referred to as ENABLE, or in any otherway producing the ENABLE signal from a derivation of PS_ON# from for example, but not limited to, the output of a PSU supervisor circuit; inverting the ENABLE signal into a signal further referred to as PS_ON_PROTECTED# sent to the power supply control unit; and distributing the ENABLE signal as a bus (said-C) to all parts of a power delivery systemfor synchronized activation and deactivation, thereby providing a means for any part(2, 3, 9) of the power delivery system to force system-wide discontinuation of power delivery.

22. A system for power delivery to any number of computer components (\<=.-,\§§-.-10), comprising: any number of soft-start switch circuits (2 and 3) according to any of claims 1-9 or any number of add-on boards according to claim 10; where said computer components are powered from separated power path/s (A to F, and B to G) with respective said soft-start switch circuit/s; and said soft-start switch circuits are working in direct conjunction with or are being anintegra| part of a DC_PSU_M (9) or said soft-start switch circuits are working inconjunction with a DC_PSU_L or an AC_PSU by additional use of/ connection to an adapter board according to claims 11 or 12 respectively.