Bidirectional battery charge-discharge control

1. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

wherein the controller is operative to switch from operating the bidirectional power converter in the first mode to operating the bidirectional power converter in the second mode in response to detecting that a magnitude of the input voltage falls below a threshold value;

wherein operation of the bidirectional power converter in the first mode includes conversion of the input voltage into a charge voltage that charges the energy storage resource; and

wherein operation of the bidirectional power converter in the second mode includes conversion of a supply voltage received from the energy storage resource into an auxiliary voltage, a combination of the auxiliary voltage and the supply voltage powering the load as a substitute to the input voltage.

2. The apparatus as in claim 1 , wherein at least one stage of the bidirectional power converter is regulated.

3. The apparatus as in claim 1 , wherein the bidirectional power converter includes:

a first power converter stage, the first power converter stage being a regulated power converter stage; and

a second power converter stage, the second power converter stage being an unregulated power converter stage.

4. The apparatus as in claim 1 , wherein the input voltage is a DC voltage; and

wherein the backup voltage is a DC voltage.

5. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

wherein the bidirectional power converter includes:

a first power converter stage, the first power converter stage being an unregulated power converter stage operative to produce an intermediate voltage from a supply voltage outputted from the energy storage resource; and

a second power converter stage, the second power converter stage being a regulated power converter stage operative to convert the intermediate voltage into a ground-isolated auxiliary voltage.

6. The apparatus as in claim 5 , wherein the second power converter stage includes an inverter operative to controllably switch a polarity of the ground-isolated auxiliary voltage.

7. The apparatus as in claim 5 , wherein the ground-isolated auxiliary voltage is offset with respect to a ground reference associated with the supply voltage outputted from the energy storage resource.

8. The apparatus as in claim 5 , wherein power delivered by the ground-isolated auxiliary voltage to the load decreases over time subsequent to initial activation of the bidirectional power converter in the second mode.

9. A method comprising:

monitoring a magnitude of an input voltage supplied to a load from an input voltage source; and

based on the magnitude of the input voltage, switching between: i) a first mode of operating a bidirectional power converter to charge an energy storage resource using the input voltage, and ii) a second mode of producing a backup voltage from the energy storage resource to power the load, the method further comprising:

via an unregulated power converter stage of the bidirectional power converter, producing an intermediate voltage from a supply voltage outputted from the energy storage resource while in the second mode; and

via a regulated power converter stage of the bidirectional power converter, converting the intermediate voltage into a ground-isolated auxiliary voltage.

10. The method as in claim 9 , wherein the switching includes:

in the first mode, controlling a first magnitude of power flow in a first direction from the input voltage through the bidirectional power converter to the energy storage resource; and

in the second mode, controlling a second magnitude of power flow in a second direction from the energy storage resource through the bidirectional power converter to produce the backup voltage.

11. The method as in claim 9 further comprising:

controllably switching a polarity of the isolated auxiliary voltage to generate the backup voltage.

12. The method as in claim 9 further comprising:

offsetting the intermediate voltage with respect to the supply voltage outputted from the energy storage resource to produce the backup voltage.

13. The method as in claim 9 , wherein an efficiency of producing the backup voltage increases over time subsequent to initial activation of the bidirectional power converter in the second mode.

14. The method as in claim 9 further comprising:

switching from operating the bidirectional power converter in the first mode to operating the bidirectional power converter in the second mode in response to detecting that the input voltage falls below a threshold value.

15. A controller operative to implement the method as claim 9 via control of a first power converter stage of the bidirectional power converter and control of a second power converter stage of the bidirectional power converter.

16. A method comprising:

monitoring a magnitude of an input voltage supplied to a load from an input voltage source;

based on the magnitude of the input voltage, switching between: i) a first mode of operating a bidirectional power converter to charge an energy storage resource using the input voltage, and ii) a second mode of producing a backup voltage from the energy storage resource to power the load, the method further comprising:

outputting a supply voltage from the energy storage resource to the bidirectional power converter, a magnitude of the supply voltage varying in a voltage range, a magnitude of the produced backup voltage falling within the voltage range during operation of the bidirectional power converter in the second mode.

17. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

wherein the bidirectional power converter includes a galvanic isolated power converter operative to convert a supply voltage received from the energy storage resource into an auxiliary voltage; and

wherein the bidirectional power converter is operative to produce the backup voltage using the auxiliary voltage.

18. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load; and

wherein the bidirectional power converter is a single power converter stage operative to provide ground reference isolation between the input voltage and the backup voltage.

19. The apparatus as in claim 18 , wherein the single power converter stage is operative to provide voltage regulation.

20. The apparatus as in claim 1 , An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

wherein the bidirectional power converter includes:

a first power converter stage, the first power converter stage being a semi-regulated power converter stage; and

a second power converter stage, the second power converter stage being a semi-regulated power converter stage.

21. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

wherein the bidirectional power converter is operative to, during the second mode:

i) convert a supply voltage received from the energy storage resource into an auxiliary voltage; and

ii) produce the backup voltage to power the load using the auxiliary voltage; and

wherein a polarity of the auxiliary voltage depends on a magnitude of the supply voltage.

22. An apparatus comprising: a bidirectional power converter; and a controller operative to: i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load; wherein the bidirectional power converter includes a first circuit path operative to receive the input voltage and, during the first mode, convert the input voltage into a charge voltage to charge the energy storage resource; and wherein the first circuit path is operative to, in the second mode, convey a supply voltage from the energy storage resource, the first circuit path converting the supply voltage into the backup voltage outputted from the first circuit path to the load.

23. The apparatus as in claim 22 , wherein the first circuit path of the bidirectional power converter includes a first node and a second node;

wherein, during the first mode of operating the bidirectional power converter, the first node receives the input voltage and the second node outputs the charge voltage to the energy storage resource; and

wherein, during the second mode of operating the bidirectional power converter, the second node receives the supply voltage from the energy storage resource and the first node outputs the backup voltage to the load.

24. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

a capacitor;

wherein a first terminal of the capacitor is operative to receive the input voltage while the bidirectional power converter is operated in the first mode; and

wherein a second terminal of the capacitor receives a charging voltage generated by the bidirectional power converter while in the first mode, the bidirectional power converter converting the input voltage into the charging voltage.

25. The apparatus as in claim 24 , wherein the second terminal of the capacitor is operative to receive a supply voltage while the bidirectional power converter is operated in the second mode; and

wherein the first terminal of the capacitor is operative to receive the backup voltage generated by the bidirectional power converter while in the second mode, the bidirectional power converter converting the supply voltage into the backup voltage.

26. An apparatus comprising:

a bidirectional power converter; and

a controller operative to:

i) monitor a magnitude of an input voltage supplied to a load from an input voltage source, and

ii) based on the magnitude of the input voltage, switch between a first mode of operating the bidirectional power converter to charge an energy storage resource using the input voltage and a second mode of producing a backup voltage from the energy storage resource to power the load;

wherein an efficiency of the bidirectional power converter producing the backup voltage during the second mode increases over time subsequent to initial activation of the bidirectional power converter in the second mode.