WIRELESS POWER SYSTEM FOR PORTABLE DEVICES UNDER ROTATIONAL MISALIGNMENT
First Claim
1. A wireless power system comprising a wireless power transmitter and a wireless power receiver capable of being operatively associated with said wireless power transmitter,(A) said wireless power transmitter comprising:
- (a) a first circuit comprising a switch network and receiving an input voltage from an external power source,(b) a second circuit comprising a variable matching circuit, operatively associated with said first circuit to appropriately bias and allow said wireless power system to regulate transmitted power, said second(c) d circuit being connected between said first circuit and a transmitter coil,(d) said transmitter coil configured to wirelessly transmit power to said wireless power receiver, and(e) a third circuit comprising a control logic block, an analog to digital converter (ADC) and a modulator/demodulator block and configured to provide a pulse width modulated signal to said first circuit, wherein said third circuit is configured to perform one or more of;
sensing the level of magnetic flux coupling between said transmitter coil of said wireless power transmitter and a receiver coil of said wireless power receiver;
driving of said first circuit to change a topology of said switch network;
driving of said second circuit to change said variable matching circuit'"'"'s impedance characteristics;
and constraining the frequency and duty cycle of said pulse width modulated signal to a range of values and varying said frequency and said duty cycle of said pulse width modulated signal within those respective ranges;
(B) said wireless power receiver for receiving and conditioning the wireless power from said wireless power transmitter, said wireless power receiver comprising;
(a) a receiver coil to receive wireless power,(b) an impedance network to control amount of wireless power received,(c) a rectifier to condition alternating current (AC) power into direct current (DC) power,(d) a protection circuit to monitor certain internal dynamic circuit characteristics of the wireless power receiver and configured to take rapid appropriate action if the circuit characteristics are not within acceptable bounds,(e) an analog to digital converter (ADC) block,(f) a modulator/demodulator block to maintain operative communication between said wireless power receiver and said wireless power transmitter,(f) a control logic to monitor internal dynamic circuit characteristics of said wireless power receiver and configured to communicate messages via said modulator/demodulator block to said wireless power transmitter;
said wireless power transmitter configured to sense said level of magnetic flux coupling under planar, orthogonal and intermediate modes of rotational misalignment and physical displacement in the X-plane, Y-plane and Z-plane,said wireless power transmitter compensating for said level of magnetic flux coupling by performing one or more of;
driving of said first circuit to change a topology of said switch network;
driving of said second circuit to change said variable matching circuit'"'"'s impedance characteristics;
and constraining said frequency and said duty cycle of said pulse width modulated signal to a range of values and varying said frequency and said duty cycle of said pulse width modulated signal within those respective ranges;
whereby said change in one or more ofsaid topology of said switch network,said impedance of variable matching circuit,said frequency range of said pulse width modulated signal,said duty cycle range of said pulse width modulated signal,ensures that said wireless power system can satisfy said wireless power receiver'"'"'s downstream load compensating for said rotational misalignment and said physical displacement in the X-plane, Y-plane and Z-plane between said transmitter coil of said wireless power transmitter and said receiver coil of said wireless power receiver.
1 Assignment
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Accused Products
Abstract
A wireless power transmitter (WPT) including a first, second, third circuit and a transmit coil for wirelessly delivering power to a wireless power receiver (WPR) including a receiver coil, rectifier, impedance network, protection circuitry, control logic, modulator/demodulator and ADC is provided. A method that enables WPT and WPR to deliver the required power to the WPR'"'"'s downstream load in planar, orthogonal and intermediate modes of WPR placement on WPT is provided. The WPR is integrated into the strap/frame or in the vital area of the device. To avoid a heated metal object safety issue, the WPT implements a metal object detect algorithm to detect metal objects and terminate transmission of power. To protect their circuitry from induced voltage spikes in excess of acceptable levels, the WPR includes a simple protection circuitry that naturally turns on and siphons out the excess power when the acceptable threshold levels are exceeded.
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Citations
20 Claims
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1. A wireless power system comprising a wireless power transmitter and a wireless power receiver capable of being operatively associated with said wireless power transmitter,
(A) said wireless power transmitter comprising: -
(a) a first circuit comprising a switch network and receiving an input voltage from an external power source, (b) a second circuit comprising a variable matching circuit, operatively associated with said first circuit to appropriately bias and allow said wireless power system to regulate transmitted power, said second (c) d circuit being connected between said first circuit and a transmitter coil, (d) said transmitter coil configured to wirelessly transmit power to said wireless power receiver, and (e) a third circuit comprising a control logic block, an analog to digital converter (ADC) and a modulator/demodulator block and configured to provide a pulse width modulated signal to said first circuit, wherein said third circuit is configured to perform one or more of; sensing the level of magnetic flux coupling between said transmitter coil of said wireless power transmitter and a receiver coil of said wireless power receiver; driving of said first circuit to change a topology of said switch network; driving of said second circuit to change said variable matching circuit'"'"'s impedance characteristics; and constraining the frequency and duty cycle of said pulse width modulated signal to a range of values and varying said frequency and said duty cycle of said pulse width modulated signal within those respective ranges; (B) said wireless power receiver for receiving and conditioning the wireless power from said wireless power transmitter, said wireless power receiver comprising; (a) a receiver coil to receive wireless power, (b) an impedance network to control amount of wireless power received, (c) a rectifier to condition alternating current (AC) power into direct current (DC) power, (d) a protection circuit to monitor certain internal dynamic circuit characteristics of the wireless power receiver and configured to take rapid appropriate action if the circuit characteristics are not within acceptable bounds, (e) an analog to digital converter (ADC) block, (f) a modulator/demodulator block to maintain operative communication between said wireless power receiver and said wireless power transmitter, (f) a control logic to monitor internal dynamic circuit characteristics of said wireless power receiver and configured to communicate messages via said modulator/demodulator block to said wireless power transmitter; said wireless power transmitter configured to sense said level of magnetic flux coupling under planar, orthogonal and intermediate modes of rotational misalignment and physical displacement in the X-plane, Y-plane and Z-plane, said wireless power transmitter compensating for said level of magnetic flux coupling by performing one or more of; driving of said first circuit to change a topology of said switch network; driving of said second circuit to change said variable matching circuit'"'"'s impedance characteristics; and constraining said frequency and said duty cycle of said pulse width modulated signal to a range of values and varying said frequency and said duty cycle of said pulse width modulated signal within those respective ranges; whereby said change in one or more of said topology of said switch network, said impedance of variable matching circuit, said frequency range of said pulse width modulated signal, said duty cycle range of said pulse width modulated signal, ensures that said wireless power system can satisfy said wireless power receiver'"'"'s downstream load compensating for said rotational misalignment and said physical displacement in the X-plane, Y-plane and Z-plane between said transmitter coil of said wireless power transmitter and said receiver coil of said wireless power receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 20)
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15. A method for establishing a sufficient and safe wireless power transfer from said wireless power transmitter to said wireless power receiver when said wireless power receiver contained in a portable device is placed on said wireless power transmitter in one of planar, orthogonal and intermediate modes, said method comprising:
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said wireless power transmitter starting up on receiving power, said wireless power transmitter probing its surface periodically for presence of said wireless power receiver, said wireless power transmitter detecting the presence of said wireless power receiver when portable device containing said wireless power receiver is placed on said surface of said wireless power transmitter, said wireless power transmitter providing power to detected said wireless power receiver, said wireless power receiver starting up on receiving power, said wireless power receiver sending messages to said wireless power transmitter, said wireless power transmitter learning about said wireless power receiver such as its type, capabilities and internal circuit characteristics such as initial voltage from said messages received from said wireless power receiver, said wireless power transmitter combining this information from said wireless power receiver with operational and circuit characteristics in said wireless power transmitter'"'"'s internal circuitry such as current, voltage, frequency, phase difference, etc., said wireless power transmitter detecting the level of magnetic flux coupling between said transmitter coil and said receiver coil, said wireless power transmitter configuring its circuitry and operating limits based on information received from said wireless power receiver as well as the detected said level of magnetic flux coupling between said transmitter coil and said receiver coil, said wireless power transmitter continuing to listen to said messages from said wireless power receiver and adjusting its operating point for appropriate power transfer to said wireless power receiver, said wireless power transmitter terminating said power transfer and returning to probing its said surface periodically when said portable device containing said wireless power receiver is removed from said surface of said wireless power transmitter, said wireless power transmitter executing metal object detect algorithm and on detection of foreign metal object, asserting a metal object alarm and aborting said power transfer if suitable user intervention is not observed in a certain interval of time, said wireless power transmitter periodically checking for removal of said foreign metal object from the said surface of said wireless power transmitter, said wireless power transmitter then returning to probing its said surface periodically on detection of removal of said foreign metal object from said surface of said wireless power transmitter, said wireless power transmitter terminating said power transfer when receiving messages from said wireless power receiver to stop the power transfer, said wireless power transmitter periodically checking for removal of said portable device containing said wireless power receiver from the said surface of said wireless power transmitter, said wireless power transmitter then returning to probing its said surface periodically on detection of removal of said portable device from said surface of said wireless power transmitter. - View Dependent Claims (16, 17)
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18. A method for avoiding heated metal safety issue caused by induced eddy currents when metal objects are placed in the magnetic flux coupling zone of said wireless power transmitter, wherein said wireless power transmitter implementing a metal object detect algorithm that said wireless power transmitter activates when said wireless power transmitter and said wireless power receiver are operating in stable power transfer,
said metal object detect algorithm periodically measuring the tank impedance as seen by said switch network of said wireless power transmitter, said metal object detect algorithm periodically measuring other internal circuit characteristics of said wireless power transmitter, said metal object detect algorithm measuring a change in said tank impedance, said metal object detect algorithm ascertaining said change in said tank impedance is not due to change in position of said wireless power receiver by checking operating and circuit characteristics in said wireless power transmitter'"'"'s internal circuitry, said metal object detect algorithm ascertaining said change in said tank impedance is not due to change in power drawn by said downstream load of said wireless power receiver by checking the total dynamic power absorbed messages received from said wireless power receiver, said metal object detect algorithm measuring an increase in the power drawn by said wireless power system, said metal object detect algorithm ascertaining said change in said tank impedance as abnormal and entering a foreign metal object detected state said wireless power transmitter asserting a metal object alarm and aborting said stable power transfer if suitable user intervention is not observed in a certain interval of time.
Specification