Supplemental power supply for a battery-powered device
A battery-powered device, such as a motorized window treatment, may provide power to an electrical load, such as a motor. The device may also include a control circuit and a communication circuit. In addition to the battery, the device may be configured to receive power from a supplemental power source, such as a solar cell or wireless RF power supply, through which to power the control and communication circuits. The device may include a voltage monitor and a switch to intelligently control whether the battery or the supplemental power source is powering the control and communication circuits.
1. An apparatus configured to control an amount of power to an electrical load coupled to a motorized window treatment, the apparatus comprising:
a battery housing configured to receive one or more batteries, the one or more batteries electrically conductively coupled to the electrical load;
a supplemental power supply comprising a supplemental power source that includes at least one of: a solar cell and an inductively coupled coil and an energy storage device, wherein the energy storage device is configured to store power received from the supplemental power source;
a monitor circuit operatively coupled to the energy storage device, the monitor circuit to generate an output signal responsive to a determination that a stored amount of power remaining in the energy storage device falls below a threshold value;
a switch operably coupled to the one or more batteries and the energy storage device, the switch reversibly transitionable between a first state and a second state; and
a control circuit communicatively coupled to the monitor circuit, the control circuit to cause the electrical load to position the motorized window treatment, the control circuit to further cause the reversible transition of the switch between the first state and the second state, such that:
in the first state, the one or more batteries supply power to the electrical load, and the supplemental power source supplies power to the control circuit; and
in the second state, the one or more batteries supply power to the electrical load, the control circuit a second energy storage device electrically conductively coupled to the electrical load; and
a second switch operably connected to the first energy storage device and the second energy storage device, the second switch reversibly transitionable between having a third state and a fourth state, such that,
in the third state, the second switch electrically decouples the supplemental power supply from the second energy storage device and electrically conductively couples the first energy storage device to the supplemental power source;
in the fourth state, the second switch electrically decouples the supplemental power supply from the first energy storage device and electrically conductively couples the second energy storage device to the supplemental power source.
2. The apparatus of claim 1 , wherein the electrical load is a motor configured to control a motorized window treatment.
3. The apparatus of claim 1 , wherein the electrical load is a sensor.
4. The apparatus of claim 1 , wherein the parameter comprises a voltage.
5. The apparatus of claim 4 , wherein the monitor circuit is a voltage monitor circuit configured to monitor an output voltage of the supplemental power supply.
6. The apparatus of claim 4 , wherein the monitor circuit comprises an analog to digital port that is on the control circuit and is configured to monitor an output voltage of the supplemental power supply.
7. The apparatus of claim 4 , wherein the voltage monitor circuit comprises a clamp circuit and a latch circuit.
8. The apparatus of claim 7 , wherein the clamp circuit and the latch circuit are configured to maintain the output voltage of the supplemental power supply between a minimum threshold and a maximum threshold.
9. The apparatus of claim 8 , wherein when the output voltage of the supplemental power supply exceeds the maximum threshold, the clamp circuit is configured to clamp the output voltage to the maximum threshold.
10. The apparatus of claim 9 , wherein when the output voltage of the supplemental power supply falls below the minimum threshold, the latch circuit is configured to unlatch, further wherein, in response to the unlatching of the latch circuit, the switch is configured to change from the second state to the first state.
11. The apparatus of claim 1 , further comprising:
a power converter circuit in electrical connection between the second energy storage device and the electrical load for providing power from the second energy storage device to the electrical load; and
a monitor circuit operably coupled to the second energy storage device, the monitor circuit configured to:
compare a voltage of the second energy storage device to a second threshold; and
based on the comparison, enable or disable the power converter circuit.
12. The apparatus of claim 11 , wherein the monitor circuit is configured to enable the power converter circuit when an output voltage of the power converter circuit is greater than an output voltage of the battery.
13. The apparatus of claim 12 , wherein the monitor circuit is configured to disable the power converter circuit when an output voltage of the power converter circuit is less than the output voltage of the battery.
14. The apparatus of claim 1 , wherein the second energy storage device is a supercapacitor.