Dual-mode energy harvesting wireless power receiver apparatus with self-reviving capabilities
Embodiments of the present disclosure describe systems, methods, and apparatuses for reviving a wireless power receiver client over-the-air. More specifically, dual-mode active/passive wireless power receiver clients are described that can passively harvest RF energy in order to obtain enough energy to rejoin a wireless power network where the client can actively harvest RF energy (the client receives directed or isolated wireless power from a wireless power transmission system). For example, a wireless power receiver client can harvest RF energy while idle or off, e.g., when no beacon or other communications are being sent or received, or, in some instances, asynchronously in order to compliment and/or protect one or more elements of the system such as, for example a radio transceiver.
1. An apparatus comprising:
peak detector circuitry communicatively coupled with an antenna and operable to detect a radio frequency (RF) field;
an active energy harvesting component enabled when the RF field is greater than an ambient threshold, the active energy harvesting component operable to receive wireless power from a wireless power transmission system (WPTS) for storage in an energy storage device; and
a passive energy harvesting component enabled when the RF field is less than the ambient threshold, the passive energy harvesting component operable to harvest ambient energy for storage in the energy storage device.
2. The apparatus of claim 1 further comprising the antenna.
3. The apparatus of claim 1 further comprising a radio operable to:
direct the antenna to establish a connection with the WPTS; and
transmit a beacon signal to the WPTS,
wherein the wireless power is received responsive to the beacon signal.
4. The apparatus of claim 3 further comprising an RF switch operable to alternately enable a primary rectification circuit or the radio.
5. The apparatus of claim 4 , wherein to enable the active energy harvesting component, the peak detector circuitry is operable to bias the RF switch to connect to the primary rectification circuit when wireless power from the WPTS is received.
6. The apparatus of claim 1 further comprising one or more matching circuits.
7. The apparatus of claim 6 , wherein the one or more matching circuits are dynamically tunable.
8. The apparatus of claim 1 further comprising the energy storage device.
9. A system comprising:
an antenna;
peak detector circuitry communicatively coupled with the antenna and operable to detect a radio frequency (RF) field;
an active energy harvesting component enabled when the RF field is greater than an ambient threshold, the active energy harvesting component operable to receive wireless power from a wireless power transmission system (WPTS) for storage in an energy storage device; and
a passive energy harvesting component enabled when the RF field is less than the ambient threshold, the passive energy harvesting component operable to harvest ambient RF energy for storage in the energy storage device.
10. The system of claim 9 further comprising the energy storage device.
11. The system of claim 9 further comprising a radio operable to:
direct the antenna to establish a connection with the WPTS; and
transmit a beacon signal to the WPTS,
wherein the wireless power is received responsive to the beacon signal.
12. The system of claim 11 further comprising an RF switch operable to alternately enable a primary rectification circuit or the radio.
13. The system of claim 12 , wherein to enable the active energy harvesting component, the peak detector circuitry is operable to bias the RF switch to connect to the primary rectification circuit when wireless power from the WPTS is received.
14. The system of claim 9 further comprising one or more matching circuits.
15. The system of claim 14 , wherein the one or more matching circuits are dynamically tunable.
16. A method comprising:
detecting a radio frequency (RF) field at an antenna;
determining whether or not the RF field is greater than an ambient threshold; and
for determining that the RF field is greater than the ambient threshold,
receiving wireless power from a wireless power transmission system (WPTS) for storage in an energy storage device;
or
for determining that the RF field is not greater than the ambient threshold,
harvesting ambient energy for storage in the energy storage device.
17. The method of claim 16 further comprising directing the antenna to establish a connection with the WPTS.
18. The method of claim 17 further comprising transmitting a beacon signal to the WPTS, wherein for determining that the RF field is greater than the ambient threshold, the receiving step comprises receiving wireless power from the WPTS in response to the transmitting.
19. The method of claim 16 further comprising storing the wireless power, or the ambient energy, in the energy storage device.
20. The method of claim 19 further comprising determining when power stored in the energy storage device meets or exceeds a wake-up power threshold.