Abstract A power supply system, for example, for use with a portable personal computer, includes a smart battery pack and a charging system. The smart battery pack is provided with a dedicated microcontroller for controlling the charging level of the battery charger system. In particular, the status of the battery including the voltage and temperature of the battery is applied to the microcontroller along with a signal representative of the current load demand of the computer system. The microcontroller, in turn, provides a control signal in the form of fixed frequency, variable duty cycle pulse width modulated (PWM) signal for controlling the charging level of the battery charger system. The duty cycle of the PWM signal is used to regulate the charging current supplied by the battery charger. In particular, the DC value of the PWM signal is used as a reference to control the charging current of the regulator to provide a variable output charging current with a relatively wide current range. As such, the battery charger is adapted to efficiently utilize the residual capacity of the battery charger system for optimizing charging of the battery packs during all operating conditions of the computer system. Moreover, the use of a PWM signal from the battery pack to control the battery charger enables a single type of battery charger to be utilized for various battery technologies.
A battery charger having a predetermined capacity for charging one or more battery cells comprising: means for providing variable charging current to said one or more battery cells, wherein said variable charging current is continuously and automatically variable from a predetermined minimum to a predetermined maximum level during all operating conditions of said battery charger; and means for providing a regulated source of DC voltage adapted to be connected to a load having a predetermined power requirement.
Claim 2
Dependent Claim
77 words
A battery charger having a predetermined capacity for charging one or more battery cells comprising: means for providing variable charging current to said one or more battery cells, wherein said variable charging current is continuously and automatically variable from a predetermined minimum to a predetermined maximum level during all operating conditions of said battery charger; and means for providing a regulated source of DC voltage adapted to be connected to a load having a predetermined power requirement.
Claim 3
Dependent Claim
49 words
A battery charger as recited in claim 1, wherein said battery charger includes means for measuring a load current; and means for limiting the charging current applied to said one or more battery cells as a function of the power requirements of the load connected to said providing means.
Claim 4
Dependent Claim
42 words
A battery charger as recited in claim 2, wherein said limiting means includes means for controlling the providing means as a function of the predetermined capacity of said battery charger and the power requirements of said load connected to said providing means.