Optimization of mobile station battery charging with a two slot charger by sharing a charging period

• US 6,242,888 B1
• Filed: 05/30/2000
• Issued: 06/05/2001
• Est. Priority Date: 05/30/2000
• Status: Expired due to Fees

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones Incorporated (Nokia Corporation)
• Inventors: Cerf, Patrice
• Primary Examiner(s): Tso, Edward H.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/583,036
• Time in Patent Office: 371 Days
• Field of Search: 320/119, 320/121, 320/139, 320/133, 320/155
• US Class Current: 320/119
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries

Abstract

A battery charging station includes a first charging circuit for charging a first battery, a second charging circuit for charging a second battery and circuitry that is responsive to a pulse width modulated signal that defines a plurality of repeating charging periods, for selectively allocating, during a single one of the charging periods, battery charging energy first to one of the first charging circuit or the second charging circuit, and then to the other charging circuit. The PWM signal is preferably received from an external battery charging circuit associated with the first battery, and during a single one of the charging periods the battery charging energy is applied first to the first charging circuit and then, if at least one criteria is met, to the second charging circuit. The at least one criteria can include an ability to develop a minimum charging voltage to the second battery during the amount of time remaining within the current charging period, after applying charging energy to the first battery. The first battery may be installed within a device, such as a cellular telephone or a personal communicator, and the PWM signal is received from a battery charging circuit installed within the device and the second battery is located within a (spare) battery pack. During a single one of the charging periods the battery charging energy is applied first to the first charging circuit for recharging the first battery and then is selectively applied to the second charging circuit for recharging the second battery.

Claims

1. A battery charging station, comprising:

a first charging circuit for charging a first battery;

a second charging circuit for charging a second battery; and

circuitry, responsive to a pulse width modulated (PWM) signal that defines a plurality of repeating charging periods, for selectively allocating, during a single one of the charging periods, battery charging energy first to one of the first charging circuit or the second charging circuit, and then to the other charging circuit.

2. A battery charging station as in claim 1, wherein the PWM signal is received from an external battery charging circuit associated with the first battery.

3. A battery charging station as in claim 1, wherein the PWM signal is received from an external battery charging circuit associated with the first battery, and wherein during a single one of the charging periods the battery charging energy is applied first to the first charging circuit and then, if at least one criteria is met, to the second charging circuit.

4. A battery charging station as in claim 3, wherein the at least one criteria includes an amount of remaining charging energy capacity within a current charging period after applying charging energy to the first battery.

5. A battery charging station as in claim 3, wherein the at least one criteria includes an ability to develop a minimum charging voltage to the second battery within a current charging period after applying charging energy to the first battery.

6. A battery charging station as in claim 1, wherein the first battery is installed within a battery powered device and the PWM signal is received from a battery charging circuit installed within the battery powered device, wherein the second battery is located within a battery pack that is installable within the same or a different battery powered device, and wherein during a single one of the charging periods the battery charging energy is applied first to the first charging circuit for recharging the first battery and then is selectively applied to the second charging circuit for recharging the second battery.

7. A method for operating a battery charging station, comprising steps of:

providing a first charging circuit for charging a first battery and a second charging circuit for charging a second battery;

electrically coupling a first battery to the first charging circuit and a second battery to the second charging circuit; and

responsive to a pulse width modulated (PWM) signal that defines a plurality of repeating charging periods, selectively allocating, during a single one of the charging periods, battery charging energy first to one of the first charging circuit or the second charging circuit, and then to the other charging circuit.

8. A method as in claim 7, wherein the PWM signal is received from an external battery charging circuit associated with the first battery.

9. A method as in claim 7, wherein the PWM signal is received from an external battery charging circuit associated with the first battery, and wherein during a single one of the charging periods the battery charging energy is applied first to the first charging circuit and then, if at least one criteria is met, to the second charging circuit.

10. A method as in claim 9, wherein the at least one criteria includes an amount of remaining charging energy capacity within a current charging period after applying charging energy to the first battery.

11. A method as in claim 9, wherein the at least one criteria includes an ability to develop a minimum charging voltage to the second battery within a current charging period after applying charging energy to the first battery.

12. A method as in claim 7, wherein the first battery is installed within a battery powered device and the PWM signal is received from a battery charging circuit installed within the battery powered device, wherein the second battery is located within a battery pack that is installable within the same or a different battery powered device, and wherein during a single one of the charging periods the battery charging energy is applied first to the first charging circuit for recharging the first battery and then is selectively applied to the second charging circuit for recharging the second battery.

13. A method for operating a battery charging station, comprising steps of:

providing a first charging circuit for charging a first battery and a second charging circuit for charging a second battery;

electrically coupling a first battery to the first charging circuit and a second battery to the second charging circuit, the first battery being associated with a pulse width modulator (PWM) battery charger circuit; and

responsive to an output of the PWM battery charger circuit, selectively allocating battery charging energy to the second charging circuit as well as to the first charging circuit, where the output of the PWM battery charger circuit comprises a composite pulse width modulated (PWM) signal that defines a plurality of repeating waveforms each comprised of a variable pulse width charger on signal and a variable pulse width charger off signal, said waveforms being interruptable for an off period that lasts more than the period of one waveform.

14. A method as in claim 13, where the step of selectively allocating comprises a step of regenerating, in the charger station, the plurality of waveforms during the off period.

15. A method as in claim 14, where the step of regenerating includes a step of clamping the variable pulse width charger on signal and the variable pulse width charger off signal at their respective values at the start of the off period.