Actively modifying output voltage of a wirelessly chargeable energy storage apparatus
Embodiments of the present disclosure describe systems, methods, and apparatuses that actively regulate output voltage of wirelessly chargeable energy storage devices, e.g., wirelessly chargeable batteries. More specifically, techniques are described to emulate low-battery behavior of a standard battery, e.g., a typical AA battery, based on an internal state of the apparatus. The internal state can be determined based on commands provided by or to the apparatus or based on analog information such as, for example, an internal charge state, e.g., of a lithium-ion battery or capacitor.
1. A wirelessly chargeable energy storage apparatus comprising:
one or more antennas for receiving wireless radio frequency (RF) power from a wireless power delivery system;
power reception circuitry for converting the received wireless RF power to direct current (DC) power;
one or more energy storage devices configured to store the converted DC power; and
voltage regulator circuitry configured to actively modify an output voltage (V OUT ) of the wirelessly chargeable energy storage apparatus based on an internal state of the apparatus, the voltage regulator circuitry including:
control circuitry coupled to the one or more energy storage devices for receiving a voltage of the one or more energy storage devices, and configured to:
determine the internal state; and
transmit an adjustment control signal including an adjustment voltage (V ADJ ) based on the internal state;
an output voltage regulator coupled to the control circuitry for receiving a feedback voltage (V FB ); and
a resistor network for modifying the adjustment voltage (V ADJ ) coupled to and between the control circuitry and the output voltage regulator,
wherein the output voltage regulator is configured to provide the output voltage (V OUT ) based on the feedback voltage (V FB ), and
wherein the feedback voltage (V FB ) is based on the adjustment voltage (V ADJ ) as modified by the resistor network.
2. The wirelessly chargeable energy storage apparatus of claim 1 , wherein the control circuitry comprises a digital processing unit configured to determine the internal state of the wirelessly chargeable energy storage apparatus.
3. The wirelessly chargeable energy storage apparatus of claim 2 , wherein the digital processing unit includes wireless communications functionality.
4. The wirelessly chargeable energy storage apparatus of claim 3 , wherein the internal state of the wirelessly chargeable energy storage apparatus is determined, at least in part, based on wireless data communication signals received by the digital processing unit.
5. The wirelessly chargeable energy storage apparatus of claim 2 further comprising a digital-to-analog converter (DAC) coupled to and between the digital processing unit and the output voltage regulator.
6. The wirelessly chargeable energy storage apparatus of claim 1 , wherein the internal state comprises a charge state of the one or more energy storage devices.
7. The wirelessly chargeable energy storage apparatus of claim 1 , wherein the one or more energy storage devices have standardized battery dimensions including a form factor of one of a: AA, AAA, C, D, 4.5-volt, 9-volt, and Lantern (spring), battery.
8. The wirelessly chargeable energy storage apparatus of claim 1 , wherein the resistor network is a three-resistor network consisting of:
a first resistor (R 1 ) coupled to and between a first node defining the output voltage (V OUT ) and a second node defining the power supply feedback voltage (V FB );
a second resistor (R 2 ) coupled to and between the second node and ground; and
a third resistor (R 3 ) coupled to and between the control circuitry and the second node.
9. The wirelessly chargeable energy storage apparatus of claim 8 , wherein the three-resistor network adheres to the following equation:
0
=
V
A
D
J
-
V
F
B
R
3
+
V
O
U
T
-
V
F
B
R
1
+
0
-
V
F
B
R
2
.
10. The wirelessly chargeable energy storage apparatus of claim 1 further comprising a housing.
11. The wirelessly chargeable energy storage apparatus of claim 10 , wherein the housing is configured in dimensions that conform to standardized battery dimensions.
12. The wirelessly chargeable energy storage apparatus of claim 10 , wherein the one or more antennas are situated within the housing.
13. The wirelessly chargeable energy storage apparatus of claim 10 , wherein the power reception circuitry is situated within the housing.
14. The wirelessly chargeable energy storage apparatus of claim 10 , wherein the voltage regulator circuitry is situated within the housing.
15. The wirelessly chargeable energy storage apparatus of claim 1 , wherein the housing comprises contacts configured to electrically couple the one or more energy storage devices with battery contact portions of a battery-powered device.
16. A method for actively regulating output voltage (V OUT ) of a wirelessly chargeable energy storage apparatus, the method comprising:
receiving, by the wirelessly chargeable energy storage apparatus, directed wireless radio frequency (RF) power from a wireless power delivery system;
converting the received wireless RF power to direct current (DC) power;
storing the converted DC power in one or more energy storage devices;
receiving, by control circuitry of the wirelessly chargeable energy storage apparatus, a voltage of the one or more energy storage devices;
determining, by the control circuitry, an internal state of the wirelessly chargeable energy storage apparatus;
transmitting, by the control circuitry, an adjustment control signal including an adjustment voltage (V ADJ ) based on the internal state;
receiving, by an output voltage regulator of the wirelessly chargeable energy storage apparatus coupled to the control circuitry, a feedback voltage (V FB );
modifying, by a resistor network coupled to and between the control circuitry and the output voltage regulator, the adjustment voltage (V ADJ ); and
providing, by the output voltage regulator, the output voltage (V OUT ) of the wirelessly chargeable energy storage apparatus based on the feedback voltage (V FB ),
wherein the feedback voltage (V FB ) is based on the adjustment voltage (V ADJ ) as modified by the resistor network.
17. The method of claim 16 , wherein the wirelessly chargeable energy storage apparatus includes a housing that conforms to standardized battery dimensions.
18. The method of claim 16 , wherein the internal state comprises a charge state of the one or more energy storage devices.
19. A voltage regulator circuit comprising:
control circuitry operable to:
receive a voltage of one or more energy storage devices of a wirelessly chargeable energy storage apparatus;
determine an internal state of the wirelessly chargeable energy storage apparatus; and
responsively induce an adjustment voltage (V ADJ ) based on the internal state;
an output voltage regulator coupled to the control circuitry, and operable to:
induce a power supply feedback voltage (V FB ); and
induce an output voltage (V OUT ) of the wirelessly chargeable energy storage apparatus based on the adjustment voltage (V ADJ ); and
a resistor network coupled to and between the control circuitry and the output voltage regulator, and operable to adjust the output voltage (V OUT ) based on the power supply feedback voltage (V FB ) and the adjustment voltage (V ADJ ).
20. The voltage regulator circuit of claim 19 , wherein the resistor network includes:
a first resistor coupled to and between a first node defining the output voltage (V OUT ) and a second node defining the power supply feedback voltage (V FB ); and
a second resistor coupled to and between the control circuitry and the second node.
21. The voltage regulator circuit of claim 19 , wherein the control circuitry includes an amplifier or comparator circuit.