USB device for making I/O pin with intact voltage during charging procedure and related method
First Claim
1. A charging control circuit of universal serial bus (USB) device, wherein the USB device is coupled to an external charger and a battery device, the USB device comprises a core circuit having a first pin and a second pin, and the charging control circuit comprises:
- a voltage source, arranged for selectively coupling to one of the first pin and the second pin according to a switch control signal;
wherein input impedance looking into the core circuit from the first pin and the second pin is configured to make the voltage source substantially intact when the voltage source is coupled to at least one of the first pin and the second pin;
wherein when the external charger provides a first supply voltage to charge the battery device to make the battery device generate a battery output voltage, the charging control circuit is arranged to be powered up by the first supply voltage, and the switch control signal is generated in response to a second supply voltage derived from the battery output voltage.
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Accused Products
Abstract
A universal serial bus device includes: a core circuit having a first pin and a second pin, and having an input impedance looking into the core circuit from the first pin and the second pin; and a charging control circuit, coupled to the core circuit, arranged for selectively providing a voltage source to one of the first pin and the second pin; wherein the input impedance of the core circuit is configured to make the voltage source substantially intact when the voltage source is coupled to one of the first pin and the second pin.
12 Citations
13 Claims
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1. A charging control circuit of universal serial bus (USB) device, wherein the USB device is coupled to an external charger and a battery device, the USB device comprises a core circuit having a first pin and a second pin, and the charging control circuit comprises:
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a voltage source, arranged for selectively coupling to one of the first pin and the second pin according to a switch control signal; wherein input impedance looking into the core circuit from the first pin and the second pin is configured to make the voltage source substantially intact when the voltage source is coupled to at least one of the first pin and the second pin; wherein when the external charger provides a first supply voltage to charge the battery device to make the battery device generate a battery output voltage, the charging control circuit is arranged to be powered up by the first supply voltage, and the switch control signal is generated in response to a second supply voltage derived from the battery output voltage. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A charging control circuit of universal serial bus (USB) device, wherein the USB device is coupled to an external charger and a battery device, the USB device comprises a core circuit having a first pin and a second pin, and the charging control circuit comprises:
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a current source, arranged for selectively coupling to one of the first pin and the second pin according to a switch control signal; wherein input impedance looking into the core circuit from the first pin and the second pin is configured to make the current source substantially intact when the current source is coupled to at least one of the first pin and the second pin; wherein when the external charger provides a first supply voltage to charge the battery device to make the battery device generate a battery output voltage, the charging control circuit is arranged to be powered up by the first supply voltage, and the switch control signal is generated in response to a second supply voltage derived from the battery output voltage. - View Dependent Claims (8, 9)
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10. A core circuit of universal serial bus (USB) device, wherein the USB device is coupled to an external charger and a battery device, and the core circuit comprises:
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a first pin and a second pin coupled to the external charger; wherein input impedance looking into the core circuit from the first pin and the second pin is configured to make a voltage source substantially intact when the voltage source is coupled to at least one of the first pin and the second pin; wherein when the external charger provides a first supply voltage to charge the battery device to make the battery device generate a battery output voltage, the core circuit is arranged to be powered up by a second supply voltage derived from the battery output voltage generated by the battery device, rather than derived from the first supply voltage, and the core circuit generates a switch control signal in response to the second supply voltage to control the voltage source to selectively couple to one of the first pin and the second pin. - View Dependent Claims (11, 12, 13)
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Specification