Wireless power system with efficiency prediction
A wireless power system has a wireless power transmitting device and a wireless power receiving device. During digital ping operations while the transmitting device and receiving device negotiate to establish a power level to use during normal operation, low-power wireless power signals may be transmitted to the receiving device from the wireless power transmitting device. Information gathered during the digital ping may be evaluated using a wireless-power-transmission-efficiency-to-digital-ping-rectifier-output-voltage relationship and using a normal-operation-wireless-power-transmission-efficiency-to-digital-ping-wireless-power-transmission-efficiency relationship to predict a wireless power transmission efficiency that would be experienced if the system were to enter normal operation. Based on this efficiency prediction, the system can issue alerts and can decide whether or not to enter normal operation.
1. A wireless power transmitting device, comprising:
wireless power transmitting circuitry configured to transmit wireless power signals to wireless power receiving circuitry that has a rectifier in a wireless power receiving device; and
control circuitry coupled to the wireless power transmitting circuitry, the control circuitry configured to:
during digital ping operations in which the wireless power signals are transmitted from the wireless power transmitting circuitry to the wireless power receiving circuitry at a first wireless power level, obtain information on operation of the wireless power transmitting circuitry and the wireless power receiving circuitry, wherein the information includes a first wireless power transfer efficiency associated with transmitting the wireless power signals from the wireless power transmitting circuitry to the wireless power receiving circuitry at the first wireless power level; and
based on the first wireless power transfer efficiency, predict a second wireless power transfer efficiency associated with transmitting the wireless power signals at a second wireless power level after the digital ping operations have been completed.
2. The wireless power transmitting device of claim 1 wherein the information comprises a first rectifier output voltage for the rectifier of the wireless power receiving circuitry and wherein the control circuitry is configured to predict the second wireless power transfer efficiency based on the first rectifier output voltage.
3. The wireless power transmitting device of claim 2 wherein the control circuitry is configured to use a predetermined efficiency-voltage relationship between digital ping wireless power transfer efficiency and digital ping rectifier output voltage in predicting the second wireless power transfer efficiency.
4. The wireless power transmitting device of claim 3 wherein the control circuitry is configured to use the first rectifier output voltage as an input to the predetermined efficiency-voltage relationship.
5. The wireless power transmitting device of claim 4 wherein the control circuitry is configured to use the first wireless power transfer efficiency as an input to the predetermined efficiency-voltage relationship.
6. The wireless power transmitting device of claim 5 wherein the control circuitry is configured to use an efficiency-efficiency relationship to predict the second wireless power transfer efficiency.
7. The wireless power transmitting device of claim 6 wherein the control circuitry is configured to use, as an input to the efficiency-efficiency relationship, an efficiency value obtained from the efficiency-voltage relationship that corresponds to operation of the rectifier at a predetermined rectifier output voltage that is lower than the digital ping rectifier output voltage.
8. The wireless power transmitting device of claim 7 wherein the control circuitry is configured to compare the second wireless power transfer efficiency to a predetermined threshold.
9. The wireless power transmitting device of claim 8 wherein the control circuitry is configured to:
in response to determining that the second wireless power transfer efficiency is greater than the predetermined threshold, control the wireless power transmitting circuitry to transmit the wireless power signals at the second wireless power level.
10. The wireless power transmitting device of claim 8 wherein the control circuitry is configured to:
in response to determining that the second wireless power transfer efficiency is greater than the predetermined threshold, direct the wireless power receiving device to issue an alert, wherein the alert indicates that a battery of the wireless power receiving device is charging.
11. The wireless power transmitting device of claim 8 wherein the control circuitry is configured to:
in response to determining that the second wireless power transfer efficiency is lower than the predetermined threshold, forgo controlling the wireless power transmitting circuitry to transmit the wireless power signals at the second wireless power level.
12. The wireless power transmitting device of claim 8 wherein the control circuitry is configured to:
in response to determining that the second wireless power transfer efficiency is lower than the predetermined threshold, direct the wireless power receiving device to issue an alert, wherein the alert indicates that wireless power transmission is not in progress.
13. The wireless power transmitting device of claim 1 further comprising a plug configured to mate with an AC-to-DC power adapter, wherein the AC-to-DC power adapter has a power rating, wherein the control circuitry is configured to:
obtain the power rating from the AC-to-DC power adapter when the plug is connected to the AC-to-DC power adapter, and
issue an alert based on the second wireless power transfer efficiency and the power rating.
14. A non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of a wireless power transmitting device that, when executed, cause a wireless power transmitting device to provide wireless power charging operations to a wireless power receiving device, the computer-executable instructions comprising instructions for:
during set-up operations, performing negotiations between the wireless power transmitting device and the wireless power receiving device to set up normal wireless power transmission operations that charge a battery in the wireless power receiving device;
during the set-up operations, determining a predicted efficiency value for wireless power transmissions from the wireless power transmitting device to the wireless power receiving device during the normal wireless power transmission operations; and
in response to determining that the predicted efficiency value is greater than a predetermined efficiency threshold, commencing the normal wireless power transmission operations.
15. The non-transitory computer-readable storage medium of claim 14 , wherein the computer-executable instructions further comprise instructions for:
using an efficiency-voltage relationship and an efficiency-efficiency relationship in determining the predicted efficiency value.
16. The non-transitory computer-readable storage medium of claim 15 , wherein the computer-executable instructions further comprise instructions for:
determining a first rectifier output voltage corresponding to operation of a rectifier in the wireless power receiving device during the set-up operations.
17. The non-transitory computer-readable storage medium of claim 16 , wherein the computer-executable instructions further comprise instructions for:
determining a first wireless power transmission efficiency value corresponding to wireless power transmission from the wireless power transmitting device to the wireless power receiving device during the set-up operations.
18. The non-transitory computer-readable storage medium of claim 17 , wherein the efficiency-voltage relationship is a relationship between output voltage of the rectifier and efficiency of the wireless power transmission during the set-up operations and wherein the computer-executable instructions further comprise instructions for:
determining an efficiency value from the efficiency-voltage relationship using as inputs: the first rectifier output voltage, the first wireless power transmission efficiency value, and a second rectifier output voltage that corresponds to operation of the rectifier during the normal wireless power transmission operations.
19. The non-transitory computer-readable storage medium of claim 18 , wherein the efficiency-efficiency relationship is a relationship between set-up operation efficiency during the set-up operations and normal operation efficiency during the normal wireless power transmission operations and wherein the computer-executable instructions further comprise instructions for:
determining the predicted efficiency value using the efficiency value determined from the efficiency-voltage relationship as an input to the efficiency-efficiency relationship.
20. The non-transitory computer-readable storage medium of claim 14 , wherein the computer-executable instructions further comprise instructions for:
in response to determining that the predicted efficiency value is greater than a predetermined efficiency threshold, causing the wireless power receiving device to present an alert indicating that the normal wireless power transmission operations are commencing.
21. The non-transitory computer-readable storage medium of claim 14 , wherein the computer-executable instructions further comprise instructions for:
in response to determining that the predicted efficiency value is greater than a predetermined efficiency threshold and before commencing the normal wireless power transmission operations, causing the wireless power receiving device to present a visual alert on a display of the wireless power receiving device indicating that the normal wireless power transmission operations are commencing.
22. A non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of a wireless power transmitting device that, when executed, cause a wireless power transmitting device to provide wireless power charging operations to a wireless power receiving device, the computer-executable instructions comprising instructions for:
during digital ping operations in which the wireless power transmitting device and the wireless power receiving device negotiate to establish a wireless power transmission level for normal wireless power transmission operations to charge a battery in the wireless power receiving device, predicting, using a wireless-power-transmission-efficiency-to-digital-ping-rectifier-output-voltage relationship and using a normal-operation-wireless-power-transmission-efficiency-to-digital-ping-wireless-power-transmission-efficiency relationship, an efficiency value for the normal wireless power transmission operations; and
in response to determining that the predicted efficiency value is greater than a predetermined efficiency threshold, commencing the normal wireless power transmission operations.