High frequency multi-level rectification
First Claim
1. A rectification circuit comprising:
- a synchronous rectifier electrically coupled to an input to receive a periodic input voltage waveform and comprising a plurality of switches, the synchronous rectifier configured to produce a first rectifier output voltage from the periodic input voltage waveform and to output the first rectifier output voltage; and
a multi-level rectifier control circuit electrically coupled to the synchronous rectifier and configured to produce and provide control signals to the synchronous rectifier to selectively actuate the plurality of switches in different actuation configurations, the multi-level rectifier control circuit configured to cycle through a plurality of different states within a period of the periodic input voltage waveform, each state of the plurality of different states corresponding to respective settings of the control signals that set the actuation configurations of the plurality of switches, wherein each state of the plurality of different states causes a voltage level of the periodic input voltage waveform to be at one of at least three different voltage levels, whereinthe multi-level rectifier control circuit is electrically coupled to the input and is further configured to adjust timing of switching between the plurality of different states based on one or more characteristics, the one or more characteristics being of electrical current at the input, or voltage levels at the input, or a combination thereof.
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Accused Products
Abstract
A multi-level rectifier is presented that is suitable for use at high frequencies, including into MHz range such as in the 6.78 MHz band used for wireless power transfer. To maintain the proper timing or switching waveform when operating at high frequencies, a feedback loop is used. The rectification circuit includes a multi-level waveform generator circuit that generates a multi-level control waveform from the input waveform and an indication of its current. The multi-level control waveform is maintained in phase with the input waveform. A control signal generation circuit receives the multi-level control waveform and generates control signals corresponding to levels of the multi-level control waveform. A synchronous rectifier receives the input waveform and includes a plurality of switches to provide an output voltage generated from the input waveform. The switches are coupled to receive the control signals and the output voltage is a function of the multi-level control waveform.
9 Citations
29 Claims
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1. A rectification circuit comprising:
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a synchronous rectifier electrically coupled to an input to receive a periodic input voltage waveform and comprising a plurality of switches, the synchronous rectifier configured to produce a first rectifier output voltage from the periodic input voltage waveform and to output the first rectifier output voltage; and a multi-level rectifier control circuit electrically coupled to the synchronous rectifier and configured to produce and provide control signals to the synchronous rectifier to selectively actuate the plurality of switches in different actuation configurations, the multi-level rectifier control circuit configured to cycle through a plurality of different states within a period of the periodic input voltage waveform, each state of the plurality of different states corresponding to respective settings of the control signals that set the actuation configurations of the plurality of switches, wherein each state of the plurality of different states causes a voltage level of the periodic input voltage waveform to be at one of at least three different voltage levels, wherein the multi-level rectifier control circuit is electrically coupled to the input and is further configured to adjust timing of switching between the plurality of different states based on one or more characteristics, the one or more characteristics being of electrical current at the input, or voltage levels at the input, or a combination thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of providing an output voltage from a periodic input voltage waveform while reducing harmonics in the periodic input voltage waveform, the method comprising:
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rectifying, via a synchronous rectifier circuit comprising a plurality of switches, the periodic input voltage waveform to produce the output voltage; producing control signals coupled to selectively actuate the plurality of switches in different switching configurations to cycle through a plurality of different states within a period of the periodic input voltage waveform, wherein each state of the plurality of different states causes a voltage level of the periodic input voltage waveform to be at one of at least three different voltage levels; and adjusting the timing of switching between the plurality of different states based on one or more characteristics, the one or more characteristics being of electrical current of the periodic input voltage waveform or voltage levels of the periodic input voltage waveform, or a combination thereof. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A rectification apparatus comprising:
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means for rectifying a periodic input voltage waveform to produce an output voltage; means for cycling through a plurality of different states within a period of the periodic input voltage waveform, wherein each state of the plurality of different states causes a voltage level of the periodic input voltage waveform to be at one of at least three different voltage levels; and means for adjusting the timing of switching between the plurality of different states based on one or more characteristics, the one or more characteristics being of electrical current of the periodic input voltage waveform, or voltage levels of the periodic input voltage waveform, or a combination thereof. - View Dependent Claims (22, 23, 24, 25, 26)
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27. An apparatus for wireless power transfer, the apparatus comprising:
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a receive circuit comprising a coil configured to generate a periodic input voltage waveform in response to an external magnetic field generated by a transmitter; and a multi-level rectification circuit coupled to the receive circuit to receive the periodic input voltage waveform therefrom at an input and configured to output a voltage for powering or charging a load, the multi-level rectification circuit including a plurality of switches controlled to cause at least three voltage levels at the input of the multi-level rectification circuit, each of the at least three voltage levels corresponding to one of a plurality of different states of the plurality of switches; and a feedback circuit coupled to the receive circuit and configured to output one or more signals indicative of one or more harmonics of the periodic input voltage waveform; and a multi-level rectifier control circuit configured to adjust the timing of switching between the plurality of different states based on the one or more signals indicative of the harmonics. - View Dependent Claims (28, 29)
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Specification