Circuit for supplementing electrical current to a peripheral device
First Claim
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1. An apparatus comprising:
- a data bus comprising a data conductor adapted to supply data signals to a sink device and a power conductor adapted to supply power from a first power source to the sink device;
a second power source connected in parallel to the power conductor between an upstream connection node and a downstream connection node along the power connector, an electrical current from the second power source combined at the downstream node with an electrical current on the power conductor from the first power source in response to a voltage on the power conductor decreasing below a threshold value; and
a recharging circuit which receives a signal provided to a light emitting diode (LED) of the sink device, the received signal having a first logic level during an inactive mode of the sink device and a second logic level during an active mode of the sink device, the recharging circuit recharging the second power source responsive to the received signal having the first logic level and interrupts recharging of the second power source responsive to the received signal transitioning to the second logic level.
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Abstract
A data bus can supply power from a first power source to a sink device. The data bus is coupled to a second power source. An electrical current from the second power source supplements an electrical current on the data bus if the voltage on the data bus decreases to less than a threshold value.
15 Citations
20 Claims
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1. An apparatus comprising:
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a data bus comprising a data conductor adapted to supply data signals to a sink device and a power conductor adapted to supply power from a first power source to the sink device; a second power source connected in parallel to the power conductor between an upstream connection node and a downstream connection node along the power connector, an electrical current from the second power source combined at the downstream node with an electrical current on the power conductor from the first power source in response to a voltage on the power conductor decreasing below a threshold value; and a recharging circuit which receives a signal provided to a light emitting diode (LED) of the sink device, the received signal having a first logic level during an inactive mode of the sink device and a second logic level during an active mode of the sink device, the recharging circuit recharging the second power source responsive to the received signal having the first logic level and interrupts recharging of the second power source responsive to the received signal transitioning to the second logic level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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sensing a first voltage on a power conductor of a data bus that supplies power from a first power source to a sink device, the first voltage sensed using a sense resistor connected in parallel to the power conductor; in response to the first voltage falling below a threshold value, providing supplemental current from a rechargeable second power source to the power conductor upstream of the sink device to supplement current from the first power source; monitoring a second voltage provided to a light emitting diode (LED) of the sink device that transitions between a high voltage level during an active mode and a low voltage level during an inactive mode; and using electrical current from the first power source to recharge the rechargeable second power source responsive to the second voltage transitioning to the low voltage level. - View Dependent Claims (11, 12, 13)
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14. An apparatus comprising:
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a powered data cable operable for connecting a host power source and a peripheral device; a chargeable power source coupled to the powered data cable, wherein the chargeable power source is operable for supplying a current that supplements a current on the powered data cable; and a charging circuit coupled to the chargeable power source and operable for receiving a signal from the peripheral device, the charging circuit configured to begin charging the chargeable power source in response to a change in state of the received signal, the signal activating a light emitting device that produces light visible to a human observer during an active mode of the peripheral device, the signal deactivating the light emitting device during a standby mode of the peripheral device and activating the charging circuit. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification