Wireless power transmitter having low noise and high efficiency, and related methods
First Claim
1. A wireless power transmitter, comprising:
- a bridge inverter includinga first switch and a second switch coupled together with a first switching node therebetween, the first and second switches being in series between a first terminal and a second terminal, the first and second terminals to receive a DC power signal comprising a first terminal voltage and a second terminal voltage lower in magnitude than the first terminal voltage; and
a first capacitor coupled between the first switching node and a first voltage;
wherein the first switch is controlled by a first control signal, and the second switch is controlled by a second control signal;
control logic configured to generate the first and second control signals to complementarily open and close the first switch and the second switch according to an operating frequency to generate an AC power signal from the DC power signal, the control logic generating the first and second control signals complimentarily opening and closing the first switch and the second switch with a first delay between generating the first control signal to open the first switch and generating the second control signal to close the second switch, and with a second delay between generating the second control signal to open the second switch and generating the first control signal to close the first switch; and
a resonant tank operably coupled to the first switching node of the bridge inverter, the resonant tank configured to receive the AC power signal and generate an electromagnetic field responsive thereto;
wherein a capacitance of the first capacitor is sufficient to lengthen, by a factor of at least 7.5, a length of time for the first switching node voltage to reach the first terminal voltage during the second delay.
1 Assignment
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Accused Products
Abstract
A wireless power transmitter comprises a bridge inverter including a first switch and a second switch coupled together with a first switching node therebetween, and a first capacitor coupled to the first switching node. The transmitter further includes control logic configured to control the first switch and the second switch according to an operating frequency to generate an AC power signal from a DC power signal, and a resonant tank operably coupled to the first switching node of the bridge inverter, the resonant tank configured to receive the AC power signal and generate an electromagnetic field responsive thereto. A method for operating the wireless power transmitter and a method for making the wireless power transmitter are also disclosed.
10 Citations
20 Claims
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1. A wireless power transmitter, comprising:
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a bridge inverter including a first switch and a second switch coupled together with a first switching node therebetween, the first and second switches being in series between a first terminal and a second terminal, the first and second terminals to receive a DC power signal comprising a first terminal voltage and a second terminal voltage lower in magnitude than the first terminal voltage; and a first capacitor coupled between the first switching node and a first voltage; wherein the first switch is controlled by a first control signal, and the second switch is controlled by a second control signal; control logic configured to generate the first and second control signals to complementarily open and close the first switch and the second switch according to an operating frequency to generate an AC power signal from the DC power signal, the control logic generating the first and second control signals complimentarily opening and closing the first switch and the second switch with a first delay between generating the first control signal to open the first switch and generating the second control signal to close the second switch, and with a second delay between generating the second control signal to open the second switch and generating the first control signal to close the first switch; and a resonant tank operably coupled to the first switching node of the bridge inverter, the resonant tank configured to receive the AC power signal and generate an electromagnetic field responsive thereto; wherein a capacitance of the first capacitor is sufficient to lengthen, by a factor of at least 7.5, a length of time for the first switching node voltage to reach the first terminal voltage during the second delay. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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operating a first switch and a second switch of a bridge inverter according to an operating frequency to generate a wireless power AC signal from a DC power signal supplied to a first terminal of the bridge inverter and a second terminal of the bridge inverter, the DC power signal comprising a first terminal voltage and a second terminal voltage lower in magnitude than the first terminal voltage, the first switch and the second switch being in series between the first and second terminals and having a first switching node therebetween, the bridge inverter having a first capacitor coupled between the first switching node and a first voltage, wherein the first switch is controlled by a first control signal, and the second switch is controlled by a second control signal, and the first and second control signals are generated to complementarily open and close the first switch and the second switch according to an operating frequency to generate an AC power signal from the DC power signal, the first and second control signals complimentarily opening and closing the first switch and the second switch with a first delay between generating the first control signal to open the first switch and generating the second control signal to close the second switch, and with a second delay between generating the second control signal to open the second switch and generating the first control signal to close the first switch; and generating the wireless power AC signal through a resonant capacitor and a transmit coil coupled to the first switching node, wherein a capacitance of the first capacitor is sufficient to lengthen, by a factor of at least 7.5, a length of time for the first switching node voltage to reach the first terminal voltage during the second delay. - View Dependent Claims (12, 13, 14)
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15. A wireless power transmitter, comprising:
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a bridge inverter including a first switch coupled between a first switching node and a first terminal, the first terminal being for receiving a first terminal voltage; a second switch coupled between the first switching node and a second terminal, the second terminal being for receiving a second terminal voltage lower in magnitude than the first terminal voltage, the first and second terminal voltages providing a DC power signal; a first capacitor coupled between the first switching node and a first voltage; a third switch coupled between a second switching node and the first terminal; a fourth switch coupled between the second switching node and the second terminal; a second capacitor coupled between the second switching node and a second voltage; control logic configured to complementarily open and close the first switch and the second switch according to an operating frequency, and to complementarily open and close the third switch and the fourth switch according to the operating frequency, to generate an AC power signal from the DC power signal; and a resonant tank operably coupled to the first switching node and the second switching node, the resonant tank configured to receive the AC power signal and generate an electromagnetic field responsive thereto; wherein a capacitance of the first capacitor and a capacitance of the second capacitor are sufficient to lengthen, by a factor of at least 7.5, a length of time for at least one of the first and second switching node voltages to rise to the first terminal voltage in response to closing of the respective one of the second and fourth switches. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification