Charge current monitoring or control in a resonance-tuned inductive charger
First Claim
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1. A battery charger for magnetically transferring power from a power source to a battery, the battery charger comprising:
- a driver circuit couplable to the power source, the driver circuit configured to output a modulated signal with energy from the power source, wherein the modulated signal has a duty cycle;
a sender-side tuned circuit magnetically and wirelessly couplable across a space to a receiver-side tuned circuit of a portable handheld electronic device, wherein the sender-side tuned circuit is configured to have a resonant frequency near or equal to the receiver-side tuned circuit;
a sender-side sensor configured to sense a voltage at a node directly connected to a high side of an inductor coil of the sender-side tuned circuit; and
a controller coupled to the driver circuit and to the sender-side sensor, wherein the controller is configured to;
cause the driver circuit to output a modulated signal at a first duty cycle having a first pulse width and at a frequency near or equal to the resonance frequency of at least one of the sender-side tuned circuit and the receiver-side tuned circuit, andmodify the first pulse width of the first duty cycle of the modulated signal based on the sensed voltage of the sender-side tuned circuit,wherein the sender-side tuned circuit includes an inductor and a capacitor, and wherein the sender-side sensor comprises a diode having a first terminal directly coupled to a high side of the inductor without any intervening components, wherein a second terminal of the diode is coupled to the controller through a low pass filter and a voltage divider, and wherein the low pass filter and the voltage divider share a resistor.
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Abstract
A battery charger and methods for magnetically transferring power from a power source to a battery is disclosed. A driver circuit outputs a modulated signal having a duty cycle from the power source to a sender-side circuit and across a space to a receiver-side tuned circuit. A sender-side sensor is configured to sense a parameter of the sender-side tuned circuit. The controller modifies the first duty cycle of the modulated signal based on the sensed parameter. A receiver-side circuit capable of determining charge status of the receiver side is also disclosed.
15 Citations
17 Claims
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1. A battery charger for magnetically transferring power from a power source to a battery, the battery charger comprising:
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a driver circuit couplable to the power source, the driver circuit configured to output a modulated signal with energy from the power source, wherein the modulated signal has a duty cycle; a sender-side tuned circuit magnetically and wirelessly couplable across a space to a receiver-side tuned circuit of a portable handheld electronic device, wherein the sender-side tuned circuit is configured to have a resonant frequency near or equal to the receiver-side tuned circuit; a sender-side sensor configured to sense a voltage at a node directly connected to a high side of an inductor coil of the sender-side tuned circuit; and a controller coupled to the driver circuit and to the sender-side sensor, wherein the controller is configured to; cause the driver circuit to output a modulated signal at a first duty cycle having a first pulse width and at a frequency near or equal to the resonance frequency of at least one of the sender-side tuned circuit and the receiver-side tuned circuit, and modify the first pulse width of the first duty cycle of the modulated signal based on the sensed voltage of the sender-side tuned circuit, wherein the sender-side tuned circuit includes an inductor and a capacitor, and wherein the sender-side sensor comprises a diode having a first terminal directly coupled to a high side of the inductor without any intervening components, wherein a second terminal of the diode is coupled to the controller through a low pass filter and a voltage divider, and wherein the low pass filter and the voltage divider share a resistor. - View Dependent Claims (2, 3, 4, 5)
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6. A method of wirelessly transferring power from a sender-side circuit to a receiver-side circuit to charge a battery on the receiver-side, the method comprising:
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starting an energizing cycle by modulating a voltage provided by a power source through an inductor of the sender-side circuit, wherein the modulated voltage has a constant predetermined frequency and a first duty cycle having a first pulse width; determining a voltage level variable corresponding to a voltage sensed at a high-side of an inductor coil of the sender-side circuit by a voltage sensor directly connected to a node at the high-side of the sender-side inductor; comparing the determined voltage level variable to a predetermined threshold voltage level; and modifying the first pulse width of the duty cycle of the modulated voltage based on the comparison of the determined voltage level variable to the predetermined threshold voltage level, wherein the sender-side circuit includes an inductor and a capacitor, wherein the sender-side sensor comprises a diode having a first terminal directly coupled to a high side of the inductor without any intervening components, wherein a second terminal of the diode is coupled to a controller through a low pass filter and a voltage divider, and wherein the low pass filter and the voltage divider share a resistor. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification