Wireless power transmitter for high fidelity communications with amplitude shift keying
Wireless power transfer systems, disclosed, include one or more circuits to facilitate high power transfer at high frequencies. Such wireless power transfer systems include a damping circuit, configured to dampen a wireless power signal such that communications fidelity is upheld at high power. The damping circuit includes at least a damping transistor that is configured to receive, from the transmitter controller, a damping signal for switching the transistor to control damping during transmission of amplitude shift keying (ASK) wireless data signals. Utilizing such systems enables wireless power transfer at high frequency, such as 13.56 MHz, at voltages over 1 Watt, while maintaining fidelity of in-band communications associated with the higher power wireless power signal.
1. A wireless power transmission system comprising:
a transmitter antenna configured to couple with a second antenna and transmit an alternating current (AC) wireless signal to the second antenna, the AC wireless signal comprising wireless power signals and amplitude shift keying (ASK) wireless data signals;
a transmitter controller that is configured to provide a driving signal for driving the transmitter antenna for the wireless power transmission system; and
an amplifier, the amplifier comprising:
an amplifier transistor that is configured to receive the driving signal and alter a direct current (DC) input power signal to generate the AC wireless signal; and
a damping circuit that is configured to dampen the AC wireless signal, wherein the damping circuit comprises a damping transistor that is configured to receive, from the transmitter controller, a damping signal for switching the damping transistor between on and off to control damping of the AC wireless signal.
2. The wireless power transmission system of claim 1 , wherein the damping circuit is in electrical parallel connection with a drain of the amplifier transistor.
3. The wireless power transmission system of claim 1 , wherein the ASK wireless data signals are in-band signals of the wireless power signals.
4. The wireless power transmission system of claim 1 , wherein the ASK wireless data signals have a high state and a low state, and
wherein the low state has a low state voltage in a range of about 93% to about 87% of a high state voltage for the high state.
5. The wireless power transmission system of claim 1 , wherein the ASK wireless data signals are a series of high and low states of the wireless power signals,
wherein the damping signal is a series of on and off signals provided to the damping transistor, and
wherein, when the ASK wireless data signals are in a high state, the damping signal is off and, when the ASK wireless data signals are in a low state, the damping signal is on.
6. The wireless power transmission system of claim 1 , wherein the damping circuit further comprises a damping resistor that is in electrical series with the damping transistor and is configured for dissipating at least some power from the wireless power signals.
7. The wireless power transmission system of claim 1 , wherein the damping circuit further comprises a damping capacitor that is in electrical series with the damping transistor.
8. The wireless power transmission system of claim 1 , wherein the damping circuit further comprises a diode that is in electrical series with the damping transistor and is configured for preventing power efficiency loss in the wireless power signals when the damping circuit is not active.
9. The wireless power transmission system of claim 1 , further comprising a choke inductor connected between a DC input power source and the amplifier transistor, the DC input power source providing the DC input power signal.
10. The wireless power transmission system of claim 1 , wherein the transmitter controller provides the damping signal to the damping transistor via a programmable pin of the transmitter controller.
11. The wireless power transmission system of claim 1 , wherein the transmitter controller is configured to provide the driving signal for driving the transmitter antenna based on an operating frequency band.
12. The wireless power transmission system of claim 11 , wherein the amplifier transistor is configured to receive the driving signal and alter the direct current (DC) input power signal to generate the AC wireless signal at the operating frequency band.
13. The wireless power transmission system of claim 1 , wherein the transmitter controller is further configured to perform one or more of encoding the ASK wireless data signals, transmitting the ASK wireless data signals, receiving the ASK wireless data signals from a wireless receiver system, or decoding the ASK wireless data signals received from the wireless receiver system.
14. A circuit for a wireless power transmitter, the wireless power transmitter configured for transmitting an alternating current (AC) wireless signal to a wireless power receiving system, the AC wireless signal comprising wireless power signals and amplitude shift keying (ASK) wireless data signals, the circuit comprising:
an amplifier, the amplifier comprising:
an amplifier transistor that is configured to receive a driving signal and alter a direct current (DC) input power signal to generate the AC wireless signal; and
a damping circuit that is configured to dampen the AC wireless signal, wherein the damping circuit comprises a damping transistor that is configured to receive, from a transmitter controller, a damping signal for switching the damping transistor between on and off to control damping of the AC wireless signal; and
a filter circuit comprising a filter capacitor and a filter inductor, the filter circuit configured for filtering based on a filter quality factor.
15. The circuit of claim 14 , wherein the filter quality factor (γ FILTER ) is defined as
γ
FILTER
=
1
R
o
L
o
C
o
.
16. The circuit of claim 14 , wherein the damping circuit further comprises a damping resistor that is in electrical series with the damping transistor and is configured for dissipating at least some power from the wireless power signals.
17. The circuit of claim 14 , wherein the damping circuit further comprises a damping capacitor that is in electrical series with the damping transistor.
18. The circuit of claim 14 , wherein the damping circuit further comprises a diode that is in electrical series with the damping transistor and is configured for preventing power efficiency loss in the wireless power signals when the damping circuit is not active.
19. A Near-Field Communications Direct Charge (NFC-DC) transmission system, the NFC-DC transmission system comprising:
a transmitter antenna configured to couple with a second antenna and transmit an alternating current (AC) wireless signal to the second antenna, the AC wireless signal comprising wireless power signals and amplitude shift keying (ASK) wireless data signals;
a transmitter controller that is configured to provide a driving signal for driving the transmitter antenna; and
an amplifier, the amplifier comprising:
an amplifier transistor that is configured to receive the driving signal and alter a direct current (DC) input power signal to generate the AC wireless signal; and
a damping circuit configured to dampen the AC wireless signal, wherein the damping circuit comprises a damping transistor that is configured to receive, from the transmitter controller, a damping signal for switching the damping transistor between on and off to control damping of the AC wireless signal.
20. The NFC-DC transmission system of claim 19 , wherein the ASK wireless data signals are compliant with standards for Type-B NFC communications.