Bit inversion for thermal mitigation in wireless power and data transfer system
A method for operating a wireless power transfer system is configured for utilizing software for the purposes of thermal mitigation, via re-encoding data in a bitstream for data communicated in-band of wireless power transfer. The data is encoded as binary messages and, during a message of the bit stream, if the number of high pulses is greater than the number of low pulses, then the message is inverted, such that each of the high pulses of the message invert to a low pulse and each of the low pulses of the message invert to a high pulse. Thus, the data signals will always have 50% or less low pulses in the bit stream.
1 . A method for operating a wireless power transfer system, the wireless power transfer system including a wireless power transmission system and a wireless power receiver system, the wireless power transmission system configured to couple with the wireless power receiver system and transmit wireless power signals to the wireless power receiver system, the method comprising:
producing data signals that are (i) representative of a binary bit stream to be encoded in-band of the wireless power signals and (ii) comprising one or more binary messages that each comprise one or more pulses, each pulse being either a high pulse or low pulse, wherein each binary message comprises a number of high pulses and a number of low pulses;
receiving input from a temperature sensor, the input indicative of a surface temperature related to one of the wireless power transmission system, the wireless power receiver system, or combinations thereof;
determining if the surface temperature exceeds a threshold maximum temperature for operating one of the wireless power transmission system, the wireless power receiver system, or combinations thereof;
responsive to the surface temperature exceeding the threshold maximum temperature, reconfiguring the data signals such that the data signals (i) are representative of an inverted binary bit stream to be encoded in-band of the wireless power signals, and (ii) comprise one or more reconfigured binary messages each corresponding to one of the one or more binary messages, wherein, if during a respective binary message of the binary bit stream the number of high pulses is greater than the number of low pulses, then a corresponding reconfigured binary message is inverted, such that each high pulse of the respective binary message inverts to a low pulse and each low pulse of the respective binary message inverts to a high pulse;
determining a driving signal for transfer of the wireless power signals, the driving signal based on an operating frequency for the wireless power signals and a power requirement for the wireless power signals;
providing the driving signal to an amplifier of the wireless power transmission system;
driving a transmitter antenna of the wireless power transmission system, by the amplifier, based on the driving signal; and
encoding the reconfigured data signals in-band of the wireless power signals.
2 . The method of claim 1 , wherein each binary message includes a flag, the flag indicating if the binary message is inverted, and
wherein each reconfigured binary message includes the flag.
3 . The method of claim 2 , wherein the flag is a bit at a beginning of each binary message or reconfigured binary message that is a high flag pulse if the binary message or reconfigured binary message is inverted and is a low flag pulse if the binary message or reconfigured binary message is not inverted.
4 . The method of claim 2 , wherein the flag (i) is a high flag pulse if the binary message or reconfigured binary message is not inverted and (ii) is a low flag pulse if the binary message or reconfigured binary message is inverted.
5 . The method of claim 1 ,
wherein the threshold maximum temperature is about 50° Celsius.
6 . The method of claim 1 , wherein the data signals are asynchronous serial data signals in accordance with a wireless power and data transfer protocol.
7 . The method of claim 6 , wherein the asynchronous serial data signals are universal asynchronous receiver-transmitter (UART) compliant data signals.
8 . The method of claim 7 , wherein the wireless power and data transfer protocol is a Near Field Communication (NFC) protocol.
9 . The method of claim 8 , wherein the UART compliant data signals are generated in accordance with the NFC data transfer protocol by packetizing the UART compliant data signals in a synchronous NFC data stream having a header with a synchronizing command and length command.
10 . The method of claim 7 , wherein the UART compliant data signals are temporarily stored in one or more buffers of the wireless power transmission system.
11 . A wireless power transmission system comprising:
a transmitter antenna configured to couple with at least one other antenna of a wireless power receiver system and transmit wireless power signals to the at least one other antenna;
a temperature sensor configured to provide temperature signals indicative of a surface temperature related to one of the wireless power transmission system, the wireless power receiver system, or combinations thereof;
a transmitter controller that is configured to:
produce data signals that are (i) representative of a binary bit stream to be encoded in-band of the wireless power signals and (ii) comprising one or more binary messages that each comprise one or more pulses, each pulse being either a high pulse or low pulse, wherein each binary message comprises a number of high pulses and a number of low pulses;
receive input from the temperature sensor, the input indicative of the surface temperature;
determine if the surface temperature exceeds a threshold maximum temperature for operating one of the wireless power transmission system, the wireless power receiver system, or combinations thereof;
reconfiguring the data signals such that the data signals (i) are representative of an inverted binary bit stream to be encoded in-band of the wireless power signals, and (ii) comprise one or more reconfigured binary messages each corresponding to one of the one or more binary messages, wherein, if during a respective binary message of the binary bit stream the number of high pulses is greater than the number of low pulses, then a corresponding reconfigured binary message is inverted, such that each high pulse of the respective binary message inverts to a low pulse and each low pulse of the repsective binary message inverts to a high pulse;
determine a driving signal for transfer of the wireless power signals, the driving signal based on an operating frequency for the wireless power signals and a power requirement for the wireless power signals; and
encode the reconfigured data signals in-band of the wireless power signals; and
an amplifier, the amplifier including at least one transistor that is configured to receive the driving signal at a gate of the at least one transistor and invert a direct power (DC) input power signal to generate the wireless power signal at the operating frequency.
12 . The wireless power transmission system of claim 11 , wherein each binary message includes a flag, the flag indicating if the binary message is inverted, and
wherein each reconfigured binary message includes the flag.
13 . The wireless power transmission system of claim 12 , wherein the flag is a bit at a beginning of each binary message or reconfigured binary message that is a high flag pulse if the binary message or reconfigured binary message is inverted and is a low flag pulse if the binary message or reconfigured binary message is not inverted.
14 . The wireless power transmission system of claim 12 , wherein the flag (i) is a high flag pulse if the binary message or reconfigured binary message is not inverted and (ii) is a low flag pulse if the binary message or reconfigured binary message is inverted.
15 . The wireless power transmission system of claim 11 ,
wherein the threshold maximum temperature is about 50° Celsius.
16 . The wireless power transmission system of claim 11 , wherein the data signals are asynchronous serial data signals in accordance with a wireless power and data transfer protocol.
17 . The wireless power transmission system of claim 16 , wherein the asynchronous serial data signals are universal asynchronous receiver-transmitter (UART) compliant data signals.
18 . The wireless power transmission system of claim 17 , wherein the wireless power and data transfer protocol is a Near Field Communication (NFC) protocol.
19 . The wireless power transmission system of claim 18 , wherein the UART compliant data signals are generated in accordance with the NFC data transfer protocol by packetizing the UART compliant data signals in a synchronous NFC data stream having a header with a synchronizing command and length command.
20 . The wireless power transmission system of claim 17 , wherein the UART compliant data signals are temporarily stored in one or more buffers of the wireless power transmission system.