Patrice R Cerf

62428888, Jun 5, 2001

May 30, 2000

9/583036

Patrice Cerf - San Diego CA

Nokia Mobile Phones - Espoo

H02J 700
H02J 714

320119

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.