Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
  • G06F1/26—Power supply means, e.g. regulation thereof
  • G06F1/266—Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips

Definitions

• a supplementary supply of a device on a limited power bus current The present invention relates to a device auxiliary supply of equipment powered by a nominal voltage bus current limited.
• host machines for data processing whether they are computers or communication platforms, generally comprise a current-limited voltage-regulated power supply bus, for example a USB bus having USB ports to which can be connected external equipment.
• a current-limited voltage-regulated power supply bus for example a USB bus having USB ports to which can be connected external equipment.
• the maximum available power allowed on the USB power bus (5V, 500mA) is generally insufficient to support these devices.
• the required power could then be obtained only by providing a current which is generally much higher than the maximum current allowed on the USB power bus.
• USB port To overcome the insufficient power rating of a USB port it was also proposed to provide power to the equipment via two USB ports using a specific cable Y. However this solution can be implemented only if the host machine has a sufficient number of USB ports to allow connection of all external equipment.
• An object of the invention is to ensure the operation of a device, in particular an external hard disk, even when the current-limited supply bus is not able to provide a sufficient current.
• a feeding device comprising no only the supply bus limited in current according to a nominal voltage of the equipment but also an auxiliary supply device comprising an energy storage member at a voltage higher than the nominal voltage associated with a voltage regulator at the nominal voltage, and a tripping member releasing the energy stored to the equipment in parallel with the power bus.
• the tripping member is sensitive to an effective voltage of the power supply bus. This takes advantage of the effective voltage drop of the power bus at the time of boot hard disk to automatically synchronize an additional power requirement with the triggering of the auxiliary power supply.
• the storage member is powered by a voltage booster circuit connected to the power supply bus. It is thus possible to ensure a charge of the electricity storage member without having recourse to any external power supply.
• FIG. 1 is a schematic representation of a first embodiment of the feed device according to the invention
• FIG. 2 is a schematic representation of a feeding device similar to that of FIG. 1 additionally equipped with a timer for triggering the auxiliary supply,
• FIG. 3 is a schematic representation of an alternative embodiment of the power supply device of FIG. 1 equipped with a timer for tripping the auxiliary power supply;
• FIG. 4 is a diagrammatic representation of a power supply device similar to that of FIG. 3 equipped with a variant of a delay device
• FIG. 5 is a schematic representation of a device similar to that of FIG. 4 equipped with a current overload protection circuit
• FIG. 6 is a schematic representation of another alternative embodiment of the device of FIG. 1;
• FIG. 7 is a schematic representation of an alternative embodiment of the device of FIG. 2;
• FIG. 8 is a schematic representation of a supply device according to the invention wherein the storage member is powered by a voltage booster circuit connected to the power bus.
• FIG. 1 illustrates a first embodiment according to which the power supply device of the invention is integrated in a host machine comprising a power supply bus 1 according to a nominal voltage Vb of a device 2 to power, here a hard disk external connected to a USB port 3 of the host machine.
• the power bus 1 is based on a voltage / voltage conversion 7 and is current limited.
• the feeding device according to the invention is integrated in a machine host also comprising a voltage regulated supply line 4 delivering an auxiliary voltage Va greater than the supply bus voltage.
• the current-limited power supply bus is a USB bus at a voltage of 5 V while the auxiliary voltage is at 12 V.
• the power supply device comprises a power storage device 5 connected to the power supply line 4 via a load resistor 8.
• the energy storage device 5 is associated with a voltage regulator 7 delivering a voltage at the nominal voltage Vb, and a trigger member 6 constituting the auxiliary supply of the equipment 1.
• the energy storage device 5 is a capacitance having a grounded terminal and an opposite terminal connected to the drain of an nMOS transistor forming the triggering element 6.
• the transistor 6 also has its source connected to the USB bus 1 and its gate associated with resistors 9, 10 bridged with the auxiliary supply line 4 so that the gate / source potential difference of the MOS transistor 6 is equal. or greater than a threshold voltage of the transistor 6 for which the transistor 6 is conducting when the effective voltage of the supply bus 1 is less than or equal to a help voltage Vh for which the auxiliary power supply is to be triggered.
• the transistor 6 When the host machine is turned on, the transistor 6 is blocked and the capacitor 5 charges until it reaches a target voltage equal to the auxiliary voltage Va.
• a device such as an external hard disk that consumes more current at startup than the USB power bus can deliver is connected to the USB 3 port, the resulting current draw causes the voltage to drop. Vb supply.
• the transistor 6 When this supply voltage reaches the value of the help voltage Vh, the transistor 6 is turned on and the capacitor 5 discharges into the circuit by delivering an auxiliary supply current in addition to the current delivered by the converter 7 and allowing a rise in the voltage of the USB power bus.
• the auxiliary current is delivered by the storage device only for a short period of time beyond which the equipment is expected to operate with a sufficiently low current to be powered by the single USB power bus.
• the auxiliary current has a peak of about 4A at the moment of connection of the equipment, immediately followed by a plateau at 2 A for about 150 ys while the nominal operating current is only 400 mA.
• FIG. 2 illustrates a supply device similar to that of FIG. 1 furthermore equipped with a timer for triggering the auxiliary power supply.
• the components identical to feeding device of Figure 1 bear the same reference numeral.
• the delay element comprises a npn transistor whose emitter is connected to ground, the collector is connected to the gate of the MOS transistor 6 at an intermediate point between the resistors 9 and 10, and the base is connected through a resistor at the output of a comparator 12 having a reverse input held at a target voltage Vc and a direct input connected to the capacitor 5 to measure the instantaneous voltage.
• the transistor 11 is conductive and the gate of the MOS transistor 6 is kept at zero so that the MOS transistor is off.
• the capacitor 5 is progressively charged.
• the transistor 11 is turned off and the auxiliary supply device then operates as described with reference to FIG.
• FIG. 3 illustrates an alternative embodiment of the device of FIG. 2.
• the components identical to the previous embodiments bear the same reference numeral.
• the transistor 11 and the comparator 12 are replaced by a simple capacitor 13 having a terminal connected to ground and an opposite terminal connected to the gate of the transistor 6 at an intermediate point between the resistors 9 and 10.
• FIG. 4 illustrates a supply device similar to that of FIG. 3, further comprising a comparator circuit comprising a transistor 11 and a comparator 12 as in the embodiment of FIG. 2, and a npn transistor 14 having its transmitter connected to FIG. the mass, its collector connected to the gate of transistor 6, and whose base initially receives a voltage making it conductive then a voltage ensuring its blocking.
• FIG. 5 illustrates a device similar to that of FIG. 4 comprising a protection circuit against current overloads.
• the power supply device comprises a pMOS transistor 15 whose drain / source connection is connected in series to the output line comprising the USB port 3, and whose gate is connected to the collector of a npn transistor 16 whose The emitter is connected to ground and the base is connected to the output of the comparator 12 through a resistor.
• the inverse input of the comparator 12 and the collector of the transistor 16 are connected to a resistance bridge 17 to 19 fixing the target voltage Vc.
• the transistor 15 is blocked as long as the capacitance 5 has not reached the target voltage Vc. No current can flow to any external equipment connected to the USB port 3.
• the MOS transistor 15 becomes on and allows the flow of a current to a device 2 connected to the USB port 3 As long as the voltage of the capacitor 5 does not fall below a critical voltage Vcc defined by the resistors 17, 18 and 19, the current can flow to the equipment.
• the capacitor 5 becomes empty up to the critical voltage at which the pMOS transistor 15 is blocked so that the system is isolated from the overload created by the short circuit. In this way the capacitance 5 is charged and the cycle is renewed as long as the short circuit is present.
• the threshold voltage of the MOS transistor In the embodiments which precede one of the operating parameters of the power supply device is the threshold voltage of the MOS transistor. This threshold voltage may vary depending on the manufacturing process of the transistor. This variation of the threshold voltage can be troublesome in some cases.
• FIG. 6 illustrates an alternative embodiment of the power supply device according to the invention in which the MOS transistor of the first embodiment is replaced by a npn transistor 21 whose emitter is connected to a Schottky diode 22, the resistor 10 being furthermore replaced by a Zener diode 23 connected firstly to ground and secondly to the base of transistor 21.
• the voltage of the base of transistor npn 21 is equal to the voltage Vz imposed by the Zener diode.
• This voltage reference is set as a function of the help voltage that one wishes to obtain, the voltage Vd of the schottky diode and the voltage Vbe of the base / emitter connection of transistor 21.
• the supply bus voltage is greater than the help voltage, one has:
• the transistor 21 is blocked. No current can flow from the capacity to the external equipment. On the contrary, when the USB bus voltage is lower than the help voltage, the voltage of the base / transmitter link of transistor 21 is greater than 0.65 and transistor 21 is on. The current can flow from the capacitor 5 to the equipment 2.
• this embodiment has the disadvantage of a loss of power in the Schottky diode.
• FIG. 7 illustrates an alternative embodiment making it possible to eliminate the consequences of a variation of the voltage threshold of a MOS transistor.
• the resistor 10 is replaced by a npn transistor 24 whose collector is connected to the gate of the MOS transistor 6, the emitter is connected to ground and the base is connected to the output a comparator 25 through a resistor whose direct input is connected to the source of the MOS transistor 6 and whose inverse input receives a voltage representative of the help voltage Vh.
• the function of the voltage comparator 25 is to control the provision of the auxiliary power stored in the capacitor 5.
• the output of the comparator 25 switches and controls the gate voltage of the transistor 6 so that it drives.
• the instantaneous bus voltage returns to its nominal value, that is to say higher than the help voltage, so that the comparator changes state and again blocks the MOS transistor 6.
• the comparator 25 thus makes it possible to circumvent the problem of uncertainty of the threshold voltage of the transistor MOS 6. However, this solution being more expensive, it will be chosen only when circumstances make it necessary.
• a voltage booster circuit connected to the power bus is provided according to the invention.
• the feed device comprises means for not only an initial load of the capacity 5 but also a maintenance of this load to fill leakage currents.
• FIG. 8 An exemplary embodiment of the voltage booster circuit is illustrated in FIG. 8 in relation to a supply device according to the embodiment illustrated in FIG.
• the converter 7 is replaced by a voltage booster stage comprising an inductor 26 having a terminal connected to the USB power supply bus and an opposite terminal connected on the one hand to the input of a diode 27 and on the other hand to the drain of a pMOS transistor 28 whose source is connected to ground and whose gate is connected to a microcontroller 29.
• the output of the diode 27 is connected firstly to the high voltage terminal of the capacitor 5 and on the other hand to an input of the microcontroller 29.
• the microcontroller 29 is also connected to the gate of an nMOS transistor 30 whose source / drain link is connected in series with the USB port 3 on the bus USB power supply.
• the MOS transistor 30 serves to isolate the external equipment as long as the capacitance 5 is not charged. It will be noted that the cost of the voltage booster stage can be particularly low insofar as the speed of charging time of the capacitor 5 is not essential. Thus, the slow slope of voltage increase advantageously dimensioning the inductance 26, the diode 27 and the transistor 28 to achieve a voltage booster stage at lower cost.
• comparator 12 has been illustrated in FIG. 4 in connection with the embodiment of FIG. 3, such an application can also be carried out in relation to the supply device such as illustrated in Figure 1.
• the invention is not limited to external hard drives
• USB can extend and also apply to other types of external element insertion on a host machine.
• Another example is the insertion of electronic equipment into an SFP cage.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Computer Hardware Design (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Direct Current Feeding And Distribution (AREA)
• Air Bags (AREA)
• Emergency Protection Circuit Devices (AREA)
• Stand-By Power Supply Arrangements (AREA)

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• 2010
  • 2010-05-27 FR FR1054063A patent/FR2960661B1/fr not_active Expired - Fee Related
• 2011
  • 2011-05-23 CN CN201180025937.9A patent/CN102906664B/zh not_active Expired - Fee Related
  • 2011-05-23 EP EP11722385.9A patent/EP2577420A1/de not_active Withdrawn
  • 2011-05-23 US US13/699,584 patent/US20130062950A1/en not_active Abandoned
  • 2011-05-23 WO PCT/EP2011/058383 patent/WO2011147785A1/fr active Application Filing
  • 2011-05-23 BR BR112012028469A patent/BR112012028469A2/pt not_active IP Right Cessation

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