NFC charging
A device includes: an NFC controller; a microcontroller; a charging circuit for an external battery; an energy recovery device; an antenna; and a switch. The NFC controller is configured to selectively control the switch in order to couple the energy recovery device to the charging circuit.
1. A device, comprising:
an NFC controller;
a microcontroller;
a battery charging circuit;
an energy recovery device;
an antenna; and
a switch that is controlled by the NFC controller to selectively couple the energy recovery device to the battery charging circuit;
wherein the microcontroller is configured to generate a control signal for controlling operation of the battery charging circuit; and
wherein the battery charging circuit is configured to measure a battery voltage level of a battery and output a charge current for application to the battery, said charge current being regulated at a constant current level, when the measured battery voltage level is between a first voltage level and second voltage level.
2. The device according to claim 1 , wherein said switch is in an open state during NFC communications using drive-reader mode or card mode.
3. The device according to claim 2 , wherein said switch is in a closed state during wireless charging cycles.
4. The device according to claim 1 , wherein said charge current is adjusted based on available field energy from a field emitted by an external charging device.
5. The device according to claim 4 , wherein at least the NFC controller and the battery charging circuit are powered by said field.
6. The device according to claim 5 wherein the microcontroller is also powered by the field.
7. The device according to claim 1 , wherein the microcontroller and/or the NFC controller is powered, in the presence of a field emitted by an external charging device, by the battery when the battery charge level is above a threshold.
8. The device according to claim 1 , wherein the NFC controller, in the presence of a field emitted by an external charging device, is configured to enter a standby mode during charging cycles.
9. The device according to claim 1 , wherein the microcontroller, in the presence of a field emitted by an external charging device, monitors the power available at an input of the battery charging circuit.
10. The device according to claim 1 , wherein the switch is of a type that is normally open.
11. The device according to claim 10 , wherein the NFC controller, in response to detection of an external wireless charging device emitting a field, is configured to close the switch coupling the energy recovery device to the charging circuit.
12. The device according to claim 1 , wherein the switch is of a type that is normally closed.
13. The device according to claim 12 , wherein the NFC controller, in response to detection of an external wireless charging device emitting a field, is configured to maintain the switch closed for coupling the energy recovery device to the battery charging circuit.
14. The device according to claim 1 , wherein the first voltage level is a discharge voltage level of the battery, and the second voltage level is an intermediate voltage level of the battery less than a maximum voltage level of the battery.
15. The device according to claim 1 , wherein the first voltage level is an intermediate voltage level of the battery greater than a discharge level of the battery, and the second voltage level is a maximum voltage level of the battery.
16. A method for control, comprising: an NFC controller; a microcontroller; a battery charging circuit; an energy recovery device; an antenna; and a switch between the energy recovery device and the battery charging circuit, wherein the method for control comprises:
using the NFC controller to selectively control the switch to couple the energy recovery device to the battery charging circuit; and
generating by the microcontroller of a control signal for controlling operation of the battery charging circuit;
measuring a battery voltage level of a battery; and
outputting a charge current from the battery charging circuit, wherein outputting comprises regulating said charge current at a constant current level when the measured battery voltage level is between a first voltage level and second voltage level.
17. The method according to claim 16 , further comprising controlling the switch in an open state during NFC communications using drive-reader mode or card mode.
18. The method according to claim 17 , further comprising control the switch in a closed state during wireless charging cycles.
19. The method according to claim 17 , further comprising:
determining presence of a field emitted by an external charging device; and
in response thereto, monitoring power available at an input of the battery charging circuit.
20. The method according to claim 16 , further comprising:
determining presence of a field emitted by an external charging device; and
in response thereto, powering the microcontroller and/or the NFC controller by the battery when the battery charge level is above a threshold.
21. The method according to claim 16 , further comprising:
determining presence of a field emitted by an external charging device; and
in response thereto, causing the NFC controller to enter a standby mode during charging cycles.
22. The method according to claim 16 , wherein the first voltage level is a discharge voltage level of the battery, and the second voltage level is an intermediate voltage level of the battery less than a maximum voltage level of the battery.
23. The device according to claim 16 , wherein the first voltage level is an intermediate voltage level of the battery greater than a discharge level of the battery, and the second voltage level is a maximum voltage level of the battery.
24. A device, comprising:
an NFC controller;
a microcontroller;
a battery charging circuit;
an energy recovery device;
an antenna; and
a switch that is controlled by the NFC controller to selectively couple the energy recovery device to the battery charging circuit;
wherein the microcontroller is configured to generate a control signal applied to the battery charging circuit for regulating a charge current; and
wherein the NFC controller and/or microcontroller, in the presence of a field emitted by an external charging device, is blocked from switching into NFC drive-reader mode as long as the charge level of the battery is below a threshold.
25. A method for control, comprising: an NFC controller; a microcontroller; a battery charging circuit; an energy recovery device; an antenna; and a switch between the energy recovery device and the battery charging circuit, the method for control comprising:
using the NFC controller to selectively control the switch to couple the energy recovery device to the battery charging circuit;
generating by the microcontroller of a control signal applied to the battery charging circuit for regulating a charge current;
determining presence of a field emitted by an external charging device; and
in response thereto, blocking a switching into NFC drive-reader mode as long as the charge level of the battery is below a threshold.