Mixed analog front-end for wireless charging
Systems, methods and apparatus for wireless charging are disclosed. An apparatus includes or operates as a wireless charging device that has a battery charging power source coupled to a charging circuit, a plurality of charging cells provided on a surface of the wireless charging device and a controller or processing circuit, which may include one or more processors. The apparatus has a high-pass filter configured to extract high-frequency components from a measurement signal representative of voltage at a transmitting coil during a charging operation, a first attenuator configured to attenuate the measurement signal and provide an attenuated measurement signal, a mixer configured to add a signal representative of the high-frequency components to the attenuated measurement signal to obtain a scaled measurement signal, and a demodulator configured to decode one or more messages associated with the charging operation from the scaled measurement signal.
1. A method for communicating with a device being charged, comprising:
extracting high-frequency components from a signal representative of tank voltage that is measured at a transmitting coil in a wireless charging device during a charging operation;
attenuating the signal representative of tank voltage to obtain an attenuated signal that has a voltage level within a range of voltage levels consistent with voltage limits associated with an input to an analog-to-digital converter circuit;
superimposing a signal representative of the high-frequency components on the attenuated signal by addition to obtain a scaled measurement signal; and
demodulating the scaled measurement signal to obtain one or more messages associated with the charging operation.
2. The method of claim 1 , further comprising:
attenuating the high-frequency components to obtain the signal representative of the high-frequency components.
3. The method of claim 1 , further comprising:
providing the scaled measurement signal to the analog-to-digital converter; and
decoding the one or more messages from a series of digitized values provided by the analog-to-digital converter, wherein the series of digitized values represents voltage samples of the scaled measurement signal over a period of time.
4. The method of claim 3 , wherein providing the scaled measurement signal to the analog-to-digital converter includes:
low-pass filtering the scaled measurement signal, wherein the analog-to-digital converter is configured to measure the tank voltage.
5. The method of claim 1 , further comprising:
using a high-pass filter to extract the high-frequency components from the signal representative of the tank voltage.
6. The method of claim 1 , wherein the high-frequency components correspond to an Amplitude Shift Key modulated signal.
7. The method of claim 6 , wherein the Amplitude Shift Key modulated signal is received from a wireless receiving device that is a participant of the charging operation.
8. A wireless charging device, comprising:
a plurality of charging cells provided on a surface of the wireless charging device;
an analog-to-digital converter circuit;
a high-pass filter configured to extract high-frequency components from a signal representative of tank voltage that is measured at a transmitting coil in one of the plurality of charging cells during a charging operation;
a first attenuator coupled to a rectifier, wherein the first attenuator and the rectifier are configured to attenuate the signal representative of tank voltage to obtain an attenuated signal that has a voltage level within a range of voltage levels consistent with voltage limits associated with an input to the analog-to-digital converter circuit;
a mixer configured to superimpose a signal representative of the high-frequency components on the attenuated signal by addition to obtain a scaled measurement signal; and
a demodulator configured to decode one or more messages associated with the charging operation from the scaled measurement signal.
9. The wireless charging device of claim 8 , further comprising:
a second attenuator configured to attenuate the high-frequency components and to provide the signal representative of the high-frequency components.
10. The wireless charging device of claim 8 , wherein the analog-to-digital is converter configured to:
receive the scaled measurement signal; and
provide a series of digitized values representing voltage samples of the scaled measurement signal over a period of time, wherein the demodulator is configured to decode the one or more messages from the series of digitized values.
11. The wireless charging device of claim 10 , further comprising:
a low-pass filter configured to filter an output of the mixer and provide the scaled measurement signal, wherein the analog-to-digital converter is configured to measure the tank voltage.
12. The wireless charging device of claim 8 , wherein the high-frequency components correspond to an Amplitude Shift Key modulated signal.
13. The wireless charging device of claim 12 , wherein the Amplitude Shift Key modulated signal is received from a wireless receiving device that is a participant of the charging operation.
14. A processor readable storage medium, comprising code for:
extracting high-frequency components from a signal representative of tank voltage that is measured at a transmitting coil in a wireless charging device during a charging operation;
attenuating the signal representative of tank voltage to obtain an attenuated signal that has a voltage level within a range of voltage levels consistent with voltage limits associated with an input to an analog-to-digital converter circuit;
superimposing a signal representative of the high-frequency components on the attenuated signal by addition to obtain a scaled measurement signal; and
demodulating the scaled measurement signal to obtain one or more messages associated with the charging operation.
15. The storage medium of claim 14 , further comprising code for:
attenuating the high-frequency components to obtain the signal representative of the high-frequency components.
16. The storage medium of claim 14 , further comprising code for:
providing the scaled measurement signal to the analog-to-digital converter; and
decoding the one or more messages from a series of digitized values provided by the analog-to-digital converter, wherein the series of digitized values represents voltage samples of the scaled measurement signal over a period of time.
17. The storage medium of claim 14 , further comprising code for:
low-pass filtering the scaled measurement signal, wherein the analog-to-digital converter is configured to measure the tank voltage.
18. The storage medium of claim 14 , further comprising code for:
using a high-pass filter to extract the high-frequency components from the signal representative of the tank voltage.
19. The storage medium of claim 14 , wherein the high-frequency components correspond to an Amplitude Shift Key modulated signal.
20. The storage medium of claim 19 , wherein the Amplitude Shift Key modulated signal is received from a wireless receiving device that is a participant of the charging operation.