Voltage regulator and control circuit for silver-zinc batteries in hearing instruments

1. An apparatus for managing power within a voltage regulating circuit of a battery-powered hearing aid device, comprising:

an input terminal of a voltage regulator receiving an input voltage (V IN ) supplied by a battery;

an output terminal of the voltage regulator providing an output voltage (V OUT ) to a hearing aid terminal electrically connected to one or more electrical components of the hearing aid device, the output voltage (V OUT ) based on the input voltage (V IN );

a sensing terminal of the voltage regulator for sensing a charging current (V SENSE ) between a charging device and charging contacts of the voltage regulating circuit; and

a switch device configured to:

transition to an ON state to allow the charging device to charge the battery based on the sensing terminal of the voltage regulator sensing the charging current (V SENSE ) between the charging device and the charging contacts; and

transition to an OFF state to block the charging contacts from receiving voltage from the battery when the output voltage (V OUT ) is present;

wherein the voltage regulator is configured to reduce a magnitude of the input voltage (V IN ) when the magnitude of the input voltage (V IN ) exceeds an input voltage threshold (V in _ thresh ) to generate the output voltage (V OUT ) having a magnitude that is less than a maximum output voltage (V out _ max ) and is further configured not to downregulate the input voltage (V IN ) when the magnitude of the input voltage (V IN ) is not greater than the input voltage threshold (V in _ thresh ).

2. The apparatus of claim 1 , wherein the switch device comprises a metal-oxide-semiconductor field-effect transistor (MOSFET).

3. The apparatus of claim 1 , wherein the switch device is integrated into the voltage regulator.

4. The apparatus of claim 1 , wherein the charging contacts of the voltage regulating circuit comprise only a positive contact and a negative contact.

5. The apparatus of any one of claims 1 and 2 - 4 , wherein the voltage regulator further comprises a switching DC-DC converter utilized to reduce the magnitude of the input voltage (V IN ) and generate the output voltage (V OUT ) by a desired ratio when the magnitude of the input voltage (V IN ) exceeds an upper plateau voltage threshold (V upper _ thresh ) that is greater than the input voltage threshold (V in _ thresh ).

6. The apparatus of claim 5 , further comprising a plurality of flying capacitors each having a substantially identical capacitance and electrically connected to the voltage regulator, the flying capacitors configured to transfer charge from the input voltage (V IN ) to the output voltage (V OUT ) when the switching DC-DC converter is being utilized.

7. The apparatus of any one of claims 1 and 2 - 4 , wherein the voltage regulator further comprises a linear DC-DC converter utilized to reduce the magnitude of the input voltage (V IN ) and output the output voltage (V OUT ) to a predetermined value when the magnitude of the input voltage (V IN ) exceeds the input voltage threshold (V in _ thresh ) and does not exceed an upper plateau voltage threshold (V upper _ thresh ).

8. The apparatus of any one of claims 1 and 2 - 4 , wherein the voltage regulator further comprises a bypass switch utilized so that the input voltage (V IN ) bypasses the voltage regulator when the input voltage (V IN ) does not exceed the input voltage threshold (V in _ thresh ).

9. The apparatus of claim 1 , wherein the battery comprises a reduced voltage battery having a maximum voltage less than the input voltage threshold (V in _ thresh ).

10. The apparatus of claim 1 , wherein the battery comprises an increased voltage battery having a maximum voltage that exceeds the input voltage threshold (V in _ thresh ).

11. A method for managing power within a voltage regulating circuit of a battery-powered hearing aid device, comprising:

a processing device of a voltage regulator of the voltage regulating circuit executing the following steps, comprising:

monitoring an input voltage (V IN ) supplied by a battery for powering one or more electrical components of the hearing aid device;

comparing a magnitude of the input voltage (V IN ) to an input voltage threshold (V in _ thresh );

monitoring a presence of a charging voltage signal (V SENSE ) indicating one of a charge current and periodic current pulses from a charging device electrically connected to the voltage regulating circuit for charging the battery;

controlling an output voltage (V OUT ) to decrease to zero to shut down the hearing aid device based on the presence of the charging voltage signal (V SENSE );

transitioning a switch device to an ON state to allow the charging device to fully charge the battery; and

when the magnitude of the input voltage (V IN ) is not greater than the input voltage threshold (V in _ thresh ), determining the battery is indicative of a reduced voltage battery and not downregulating the input voltage (V IN ) for powering the one or more electrical components; and

when the magnitude of the input voltage (V IN ) is greater than the input voltage threshold (V in _ thresh ), determining the battery is indicative of an increased voltage battery and reducing the input voltage (V IN ) to output the output voltage (V OUT ) having a magnitude that is less than a maximum output voltage (V out _ max ) for powering the one or more electrical components.

12. The method of claim 11 , further comprising transitioning a switch device to an OFF state when the one or more electrical components are being powered by the output voltage (V OUT ), the OFF state of the switch device blocking exposure of voltage to charging contacts of the voltage regulating circuit.

13. The method of any one of claims 11 and 12 , wherein reducing the input voltage (V IN ) to output the output voltage (V OUT ) having the magnitude that is less than the maximum output voltage (V out _ max ) comprises:

comparing the input voltage (V IN ) to an upper voltage plateau threshold (V upper _ thresh ), the upper voltage plateau threshold (V upper _ thresh ) is greater than the input voltage threshold (V in _ thresh ); and

when the input voltage (V IN ) exceeds the upper voltage plateau threshold (V upper _ thresh ), proportionally reducing the input voltage (V IN ) by a switching DC-DC converter of the voltage regulator to generate the output voltage (V OUT ) that does not violate the maximum output voltage (V out _ max ).

14. The method of claim 13 , further comprising, when the input voltage exceeds the input voltage threshold (V in _ thresh ) and does not exceed the upper voltage plateau threshold (V upper _ thresh ), reducing the input voltage (V IN ) by a linear DC-DC converter to deliver a constant predetermined output voltage (V OUT ) that does not violate the maximum output voltage (V out _ max ).

15. The method of any one of claims 11 and 12 , wherein the electrical components of the hearing aid device comprise at least one of a microphone, a signal processor, an audio amplifier, related electrical circuitry, and a loudspeaker.

16. The method of any one of claims 11 and 12 , wherein the reduced voltage battery comprises a zinc-air battery.

17. The method of any one of claims 11 and 12 , wherein the reduced voltage battery comprises a nickel-metal hydride (NiMH) battery.

18. The method of any one of claims 11 and 12 , wherein the increased voltage battery comprises a rechargeable silver-zinc battery.

19. The method of any one of claims 11 and 12 , further comprising bypassing the voltage regulator when the magnitude of the input voltage (V IN ) is not greater than the input voltage threshold (V in _ thresh ).