USB power converter with bleeder circuit for fast correction of output voltage by discharging output capacitor
First Claim
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1. A universal serial bus (USB) charger for providing power to a client device comprising:
- a USB connector configured to interface with the client device, and to receive a request for an output voltage at one of a plurality of voltage levels including a first voltage level and a second voltage level, the second voltage level higher than the first voltage level;
a converter circuit, an output of the converter circuit coupled to the USB connector, the converter circuit configured to convert an input voltage level to an output voltage level at one of the plurality of voltage levels including the first voltage level and the second voltage level, the converter circuit comprising an output capacitor coupled to the USB connector;
a bleeder circuit coupled to the output capacitor of the converter circuit, the bleeder circuit configured to discharge the output capacitor of the converter circuit responsive to the output voltage level of the converter circuit being greater than the first voltage level, the first bleeder circuit comprising;
a first switch coupled to the output controller,a first bleeder resistor coupled to the output capacitor and the first switch, the first bleeder resistor configured to discharge the output capacitor when the first switch is closed,a second switch coupled to the output controller, anda second bleeder resistor coupled to the output capacitor and the second switch, the second bleeder resistor having a resistance higher than the first bleeder resistor, the second bleeder resistor configured to provide a slow discharge of the output capacitor when the first switch is opened; and
an output controller coupled to the converter circuit and the bleeder circuit, the output controller configured to;
responsive to a client device not being connected to the USB connector and the output voltage level of the converter circuit being controlled to be at the second voltage level;
control the output voltage level of the converter circuit to be at the first voltage level,turn on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at the second voltage level, andturn off the first switch and the second switch responsive to determining that the first switch and the second switch have been on for a set amount of time.
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Abstract
A universal serial bus (USB) charger provides power to a client device. A USB connector interfaces with a client device and receives a request for the output voltage of the USB charger to be at a specific value. If the requested voltage level is lower than the current output voltage level, the output voltage level is set to the requested level and a bleeder circuit is enabled to discharge the output capacitor of the USB charger.
165 Citations
19 Claims
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1. A universal serial bus (USB) charger for providing power to a client device comprising:
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a USB connector configured to interface with the client device, and to receive a request for an output voltage at one of a plurality of voltage levels including a first voltage level and a second voltage level, the second voltage level higher than the first voltage level; a converter circuit, an output of the converter circuit coupled to the USB connector, the converter circuit configured to convert an input voltage level to an output voltage level at one of the plurality of voltage levels including the first voltage level and the second voltage level, the converter circuit comprising an output capacitor coupled to the USB connector; a bleeder circuit coupled to the output capacitor of the converter circuit, the bleeder circuit configured to discharge the output capacitor of the converter circuit responsive to the output voltage level of the converter circuit being greater than the first voltage level, the first bleeder circuit comprising; a first switch coupled to the output controller, a first bleeder resistor coupled to the output capacitor and the first switch, the first bleeder resistor configured to discharge the output capacitor when the first switch is closed, a second switch coupled to the output controller, and a second bleeder resistor coupled to the output capacitor and the second switch, the second bleeder resistor having a resistance higher than the first bleeder resistor, the second bleeder resistor configured to provide a slow discharge of the output capacitor when the first switch is opened; and an output controller coupled to the converter circuit and the bleeder circuit, the output controller configured to; responsive to a client device not being connected to the USB connector and the output voltage level of the converter circuit being controlled to be at the second voltage level; control the output voltage level of the converter circuit to be at the first voltage level, turn on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at the second voltage level, and turn off the first switch and the second switch responsive to determining that the first switch and the second switch have been on for a set amount of time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for providing power to a client device in a plurality of voltage levels including a first voltage level and a second voltage level, the second voltage level higher than the first voltage level, the method comprising:
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determining, by a universal serial bus (USB) charger, whether the client device is connected to the USB charger; and responsive to determining that the client device is not connected to the USB charger and an output voltage of the USB charger is set to the second voltage level, the second voltage level higher than the first voltage level; setting the output voltage level to the first voltage level; and enabling a bleeder circuit, the bleeder circuit configured to discharge an output capacitor of the USB charger, the bleeder circuit including a first switch, a first bleeder resistor coupled to the output capacitor and the first switch, a second switch, and a second bleeder resistor coupled to the output capacitor and the second switch, comprising; turning on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at the second voltage level, turning off the first switch responsive to determining that the output voltage level of the USB charger is at a third voltage level, the third voltage level higher than the first voltage level and lower than the second voltage level, and turning off the second switch responsive to determining that the output voltage level of the USB charger is within a threshold level of the first voltage level. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A universal serial bus (USB) charger for providing power to a client device comprising:
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a USB connector configured to interface with the client device, and to receive a request for an output voltage at one of a plurality of voltage levels including a first voltage level and a second voltage level; a converter circuit, an output of the converter circuit coupled to the USB connector, the converter circuit configured to convert an input voltage level to an output voltage level, the converter circuit comprising an output capacitor coupled to the USB connector; a bleeder circuit coupled to the output capacitor of the converter circuit, the bleeder circuit configured to discharge the output capacitor of the converter circuit responsive to the output voltage level of the converter circuit being greater than the first voltage level, the bleeder circuit comprising; a first switch coupled to the output controller, a first bleeder resistor coupled to the output capacitor and the first switch, the first bleeder resistor configured to discharge the output capacitor when the first switch is closed, a second switch coupled to the output controller, and a second bleeder resistor coupled to the output capacitor and the second switch, the second bleeder resistor having a resistance higher than the first bleeder resistor, the second bleeder resistor configured to provide a slow discharge of the output capacitor when the first switch is opened; and an output controller coupled to the converter circuit and the bleeder circuit, the output controller configured to; turn on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level; turn off the first switch responsive to determining that the output voltage level of the USB charger is at a third voltage level, the third voltage level higher than the first voltage level and lower than the second voltage level; and turn off the second switch responsive to determining that the output voltage level of the USB charger is within a threshold level of the first voltage level. - View Dependent Claims (17, 18, 19)
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Specification