Wireless power transfer with integrated communications
A wireless power transmitter can include an inverter that receives a DC input and generates an AC output to drive a wireless power transmit coil coupled to an output of the inverter as well as voltage and current sensors that measure the DC input. The wireless power transmitter can further include a power management accumulator including hardware that receives voltage and current samples from the voltage and current sensors and multiplies corresponding voltage and current samples to produce power samples and memory locations that store corresponding voltage, current, and power samples. The wireless power transmitter can still further include a programmable controller that controls switching devices of the inverter responsive at least in part to the voltage, current and power samples stored in the memory locations of the power management accumulator.
1. A wireless power transmitter comprising:
an inverter that receives a direct current (DC) input and generates an alternating current (AC) output to drive a wireless power transmit coil coupled to an output of the inverter;
voltage and current sensors that measure the DC input;
a power management accumulator; and
a programmable controller;
wherein the power management accumulator further comprises:
dedicated hardware that receives voltage and current samples from the voltage and current sensors and multiplies corresponding voltage and current samples to produce corresponding power samples, thereby reducing computational burden on the programmable controller; and
memory locations that store the corresponding voltage, current, and power samples; and
wherein the programmable controller controls switching devices of the inverter responsive at least in part to the corresponding voltage, current and power samples stored in the memory locations of the power management accumulator.
2. The wireless power transmitter of claim 1 wherein the memory locations form a circular buffer.
3. The wireless power transmitter of claim 1 wherein the programmable controller receives information from a wireless power receiver indicating power received by the wireless power receiver over a time interval.
4. The wireless power transmitter of claim 3 wherein the programmable controller compares the power received by the wireless power receiver over the time interval to the corresponding power samples stored in the memory locations of the power management accumulator for the time interval to detect a foreign object.
5. The wireless power transmitter of claim 4 wherein the programmable controller reduces or stops wireless power transfer responsive to detecting the foreign object.
6. The wireless power transmitter of claim 1 wherein two or more of the inverter, the power management accumulator, and the programmable controller are combined into a single integrated circuit.
7. The wireless power transmitter of claim 1 further comprising a hardware mean squared current calculator that computes values corresponding to a root mean squared (RMS) current delivered to the wireless power transmit coil.
8. The wireless power transmitter of claim 7 wherein the values corresponding to the RMS current delivered to the wireless power transmit coil are stored in the memory locations of the power management accumulator.
9. The wireless power transmitter of claim 7 wherein the hardware mean squared current calculator includes dedicated hardware blocks that receive capacitor voltage samples of a voltage appearing across a capacitor in series with the wireless power transmit coil, determine a current through the capacitor from the capacitor voltage samples, and calculate values corresponding to the RMS current delivered to the wireless power transmit coil from the determined current.
10. The wireless power transmitter of claim 7 wherein three or more of the inverter, the power management accumulator, the mean squared current calculator, and the programmable controller are combined into a single integrated circuit.
11. An integrated circuit for use in a wireless power transfer system, the integrated circuit comprising:
a plurality of switching devices operable as an inverter of a wireless power transmitter;
voltage and current sensors coupled to the plurality of switching devices that measure a direct current (DC) input into the switching devices;
a power management accumulator; and
a programmable controller;
wherein the power management accumulator further comprises:
dedicated hardware that receives voltage and current samples from the voltage and current sensors and multiplies corresponding voltage and current samples to produce corresponding power samples, thereby reducing computational burden on the programmable controller; and
memory locations that store the corresponding voltage, current, and power samples; and
wherein the programmable controller controls the plurality of switching devices responsive at least in part to the corresponding voltage, current or power samples stored in the memory locations of the power management accumulator.
12. The integrated circuit of claim 11 wherein the memory locations form a circular buffer.
13. The integrated circuit of claim 11 wherein the programmable controller receives information from a wireless power receiver indicating power received by the wireless power receiver over a time interval.
14. The integrated circuit of claim 13 wherein the programmable controller compares the power received by the wireless power receiver over the time interval to the corresponding power samples stored in the memory locations of the power management accumulator for the time interval to detect a foreign object.
15. The integrated circuit of claim 14 wherein the programmable controller reduces or stops wireless power transfer responsive to detecting the foreign object.
16. The integrated circuit of claim 11 further comprising a hardware mean squared current calculator that computes values corresponding to root mean squared (RMS) current through the wireless power transfer coil.
17. The integrated circuit of claim 16 wherein the values corresponding to the RMS current through the wireless power transfer coil are stored in the memory locations of the power management accumulator.
18. The integrated circuit of claim 16 wherein the hardware mean squared current calculator includes dedicated hardware blocks that receive capacitor voltage samples of a voltage appearing across a capacitor in series with the wireless power transfer coil, determine a current through the capacitor from the capacitor voltage samples, and calculate values corresponding to the RMS current through the wireless power transfer coil from the determined current.
19. An integrated circuit for use in a wireless power transfer system, the integrated circuit comprising:
a plurality of switching devices operable as a rectifier of a wireless power receiver;
voltage and current sensors coupled to the plurality of switching devices that measure a direct current (DC) output from the switching devices;
a power management accumulator; and
a programmable controller;
wherein the power management accumulator further comprises:
dedicated hardware that receives voltage and current samples from the voltage and current sensors and multiplies corresponding voltage and current samples to produce corresponding power samples, thereby reducing computational burden on the programmable controller; and
memory locations that store the corresponding voltage, current, and power samples; and
wherein the programmable controller controls the plurality of switching devices responsive at least in part to the corresponding voltage, current or power samples stored in the memory locations of the power management accumulator.
20. The integrated circuit of claim 19 wherein the memory locations form a circular buffer.
21. The integrated circuit of claim 19 wherein the programmable controller transmits information to a wireless power transmitter indicating power received by the wireless power receiver over a time interval.
22. The integrated circuit of claim 19 further comprising a hardware mean squared current calculator that computes values corresponding to a root mean squared (RMS) current through the wireless power transfer coil.
23. The integrated circuit of claim 22 wherein the values corresponding to the RMS current through the wireless power transfer coil are stored in the memory locations of the power management accumulator.
24. The integrated circuit of claim 22 wherein the hardware mean squared current calculator includes dedicated hardware blocks that receive capacitor voltage samples of a voltage appearing across a capacitor in series with the wireless power transfer coil, determine a current through the capacitor from the capacitor voltage samples, and calculate values corresponding to the RMS current through the wireless power transfer coil from the determined current.