Automatic gain control for communications demodulation in wireless power transmitters
A wireless transmission system includes a transmitter antenna, a sensor, a demodulation circuit, and a transmitter controller. The sensor is configured to detect electrical information associated with AC wireless signals, the electrical information including, at least, a voltage of the AC wireless signals. The demodulation circuit is configured to receive the electrical information from the at least one sensor, detect a change in the electrical information, determine if the change in the electrical information meets or exceeds one of a rise threshold or a fall threshold, if the change exceeds one of the rise threshold or the fall threshold, generate an alert, and output a plurality of data alerts. The transmitter controller is configured to receive the plurality of data alerts from the demodulation circuit and decode the plurality of data alerts into the wireless data signals.
1. A wireless power transfer system configured to transfer alternating current (AC) wireless signals, the AC wireless signals including wireless power signals and wireless data signals, the wireless power transfer system comprising:
a medical device comprising a wireless receiver system including a receiver antenna, the wireless receiver system configured to alter electrical characteristics of the AC wireless signals; and
a wireless transmission system including:
a transmitter antenna configured to couple with the receiver antenna of the medical device and transmit the AC wireless signals to the receiver antenna;
at least one sensor configured to detect electrical information associated with the electrical characteristics of the AC wireless signals, the electrical information including one or more of a current of the AC wireless signals, a voltage of the AC wireless signals, a power level of the AC wireless signals, or combinations thereof;
a demodulation circuit including a slope detector circuit and a high pass filter circuit, the high pass filter circuit configured to variably alter a resistance of the high pass filter based on the electrical information,
the demodulation circuit configured to (i) receive the electrical information from the at least one sensor, (ii) detect a change in the electrical information, (iii) determine if the change in the electrical information meets or exceeds one of a rise threshold or a fall threshold, (iv) if the change exceeds one of the rise threshold or the fall threshold, generate an alert, (v) and output a plurality of data alerts; and
a transmitter controller configured to (i) receive the plurality of data alerts from the demodulation circuit, and (ii) decode the plurality of data alerts into the wireless data signals.
2. The wireless power transfer system of claim 1 , wherein the wireless data signals are encoded by the wireless receiver system as amplitude shift keying (ASK) data signals.
3. The wireless power transfer system of claim 1 , wherein the wireless receiver system encodes the wireless data signals as high threshold and low threshold voltages of the AC wireless signals.
4. The wireless power transfer system of claim 3 , wherein the rise threshold is associated with the high threshold voltage and the fall threshold is associated with the low threshold voltage.
5. The wireless power transfer system of claim 3 , wherein the wireless data signals are encoded as pulse width encoded wireless data signals.
6. The wireless power transfer system of claim 1 , wherein the electrical information includes a voltage of the wireless power signals, and
wherein the slope detector circuit is configured to determine a voltage rate of change for the voltage of the wireless power signals.
7. The wireless power transfer system of claim 6 , wherein the demodulation circuit includes a comparator circuit configured to (i) receive the voltage rate of change, (ii) compare the voltage rate of change to a rising rate of change, and (iii) determine that the change in the electrical information meets or exceeds the rise threshold, if the voltage rate of change meets or exceeds the rising rate of change.
8. The wireless power transfer system of claim 6 , wherein the demodulation circuit includes a comparator circuit configured to (i) receive the voltage rate of change, (ii) compare the voltage rate of change to a falling rate of change, and (iii) determine that the change in the electrical information meets or exceeds the fall threshold, if the voltage rate of change meets or exceeds the falling rate of change.
9. The wireless power transfer system of claim 6 , wherein the demodulation circuit includes a comparator circuit configured to (i) receive the voltage rate of change, (ii) compare the voltage rate of change to a rising rate of change, (iii) determine that the change in the electrical information meets or exceeds the rise threshold, if the voltage rate of change meets or exceeds the rising rate of change, (iv) compare the voltage rate of change to a falling rate of change, and (v) determine that the change in the electrical information meets or exceeds the fall threshold, if the voltage rate of change meets or exceeds the falling rate of change.
10. The wireless power transfer system of claim 9 , wherein the demodulation circuit includes a set/reset (SR) latch in operative communication with the comparator circuit.
11. The wireless power transfer system of claim 1 , wherein the transmitter antenna and the receiver antenna are configured to operate based on an operating frequency of about 6.78 megahertz (MHz).
12. The wireless power transfer system of claim 1 , wherein the wireless data signals include a voltage of power received by the wireless receiver system from the wireless transmission system.
13. The wireless power transfer system of claim 12 , wherein the wireless receiver system further includes a power conditioning system, the power conditioning system including a rectifier and configured to receive the wireless power signals of the AC wireless signals, convert the wireless power signals to a direct current (DC) power signal, and output the DC power signal, and
wherein the voltage of power received is a voltage at the output of the power conditioning system.
14. The wireless power transfer system of claim 1 , wherein the wireless data signals are generated by altering electrical characteristics of the AC wireless signals at the receiver antenna.
15. The wireless power transfer system of claim 1 , wherein the wireless transmission system is configured to transmit the AC wireless signals to the wireless receiver system when the medical device resides within a human body.
16. The wireless power transfer system of claim 1 , wherein the medical device is configured as an implantable medical device.