Active rectifier and wireless power receiving apparatus using the same that can reduce reverse current leakage
First Claim
1. An active rectifier, comprising:
- first and fourth switches configured to be turned on while a voltage of an alternating current (AC) input is negative so as to apply a current of the AC input to a rectifying capacitor;
second and third switches configured to be turned on while the voltage of the AC input is positive so as to apply the current of the AC input to the rectifying capacitor;
a synchronization control unit configured to compensate for a delay time of a comparator configured to detect zero-crossing of the AC input, by switching the first, second, third, and fourth switches; and
a first level shifter and a second level shifter configured to compensate for a threshold voltage by switching the third switch and the fourth switch, respectively.
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Accused Products
Abstract
An active rectifier and a wireless power reception apparatus using the same are disclosed herein. The active rectifier includes first and fourth switches, second and third switches, and a synchronization control unit. The first and fourth switches are turned on while the voltage of an alternating current (AC) input is negative, and apply the current of the AC input to a rectifying capacitor. The second and third switches are turned on while a voltage of the AC input is positive, and apply the current of the AC input to the rectifying capacitor. The synchronization control unit compensates for the delay time of the comparator for detecting zero-crossing of the AC input so as to switch the first to fourth switches.
9 Citations
10 Claims
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1. An active rectifier, comprising:
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first and fourth switches configured to be turned on while a voltage of an alternating current (AC) input is negative so as to apply a current of the AC input to a rectifying capacitor; second and third switches configured to be turned on while the voltage of the AC input is positive so as to apply the current of the AC input to the rectifying capacitor; a synchronization control unit configured to compensate for a delay time of a comparator configured to detect zero-crossing of the AC input, by switching the first, second, third, and fourth switches; and a first level shifter and a second level shifter configured to compensate for a threshold voltage by switching the third switch and the fourth switch, respectively. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A wireless power reception apparatus, comprising:
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a resonant reception coil configured to receive a radio signal, and generate an AC input from the radio signal; an active rectifier for comprising first and fourth switches configured to be turned on while a voltage of the AC input is negative so as to apply a current of the AC input to a rectifying capacitor, second and third switches configured to be turned on while the voltage of the AC input is positive so as to apply the current of the AC input to the rectifying capacitor, a synchronization control unit configured to compensate for a delay time of a comparator configured to detect zero-crossing of the AC input by switching the first, second, third, and fourth switches, and a first level shifter and a second level shifter configured to compensate for a threshold voltage by switching the third switch and the fourth switch, respectively; and a regulator configured to generate a DC voltage from a voltage charged in the rectifying capacitor, wherein the first, second, third, and fourth switches are implemented using N channel field effect transistors.
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8. A delay compensation method of controlling a synchronization of an active rectifier, the active rectifier comprising first and fourth switches turned on while a voltage of an AC input is negative so as to apply a current of the AC input to a rectifying capacitor, and second and third switches turned on while a voltage of the AC input is positive so as to apply a current of the AC input to the rectifying capacitor, the delay compensation method comprising:
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generating a first coarse delay comparison signal by delaying a comparison signal, output from a comparator configured to detect zero-crossing of the AC input, by a first delay time; selecting a first candidate delay signal from candidate delay signals obtained by delaying the first coarse delay comparison signal by first different fine delay times; determining a second coarse delay time such that a phase of a first reference delay signal, obtained by further delaying the selected first candidate delay signal by a compensation delay time, is synchronized with a phase of the comparison signal; selecting a second candidate delay signal from candidate delay signals obtained by further delaying a second coarse delay comparison signal by second different fine delay times, wherein the second coarse delay comparison signal is delayed by the determined second coarse delay time; determining a fine delay time such that a phase of a second reference delay signal, obtained by further delaying the selected second candidate delay signal by another compensation delay time, is synchronized with the phase of the comparison signal; and outputting a third candidate delay signal, corresponding to the determined fine delay time, as a switch control signal. - View Dependent Claims (9)
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10. A method of controlling a synchronization of an active rectifier, the active rectifier comprising first and fourth switches implemented using N channel field effect transistors and turned on while a voltage of an AC input is negative so as to apply a current of the AC input to a rectifying capacitor, second and third switches implemented using N channel field effect transistors and turned on while the voltage of the AC input is positive to apply the current of the AC input to the rectifying capacitor, a synchronization control unit configured to compensate for a delay time of a first, second, third, and fourth comparator configured to detect zero-crossing of the AC input, by switching the first, second, third, and fourth switches, and a first level shifter and a second level shifter configured to compensate for a threshold voltage by switching the third switch and the fourth switch, respectively, the method comprising:
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outputting a first switch control signal by compensating a first comparison signal for a delay of the first comparator, wherein the first comparison signal is output by the first comparator so as to be activated in response to the AC input turning from positive to negative and deactivated in response to the AC input turning from negative to positive; outputting a second switch control signal by compensating a second comparison signal for a delay of the second comparator, wherein the second comparison signal is output by the second comparator so as to be activated in response to the AC input turning from negative to positive and deactivated in response to the AC input turning from positive to negative; outputting a third switch control signal by compensating a third comparison signal for a delay of the third comparator, the third comparison signal being output by the third comparator so as to be activated in response to the AC input turning from negative to positive and deactivated in response to the AC input turning from positive to negative; outputting a fourth switch control signal by compensating a fourth comparison signal for a delay of the fourth comparator, wherein the fourth comparison signal is output by the fourth comparator so as to be activated in response to the AC input turning from positive to negative and deactivated in response to the AC input turning from negative to positive; turning on the first and the fourth switches using the first and the fourth switch control signals while the voltage of the AC input is negative, so as to apply the current of the AC input to the rectifying capacitor; and turning on the second and the third switches using the second and the third switch control signals while the voltage of the AC input is positive, so as to apply the current of the AC input to the rectifying capacitor.
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Specification