www.SiliconStandard.com

6 of 10

SS4003

2/01/2005 Rev.1.01

PBV

PPV

PMV

PEV

PLV

PCV

Trickle Charge

CC Charge

CV Charge

Finished

Capacity

Voltage Thresholds

In conjunction with monitoring the voltage at pin I for charge/discharge currents, the SS4003 monitors

the battery potential through the pin V. The voltage potential is determined through a resistor-divider

network on tips of cells. The battery voltage is obtained by measuring the input voltages on tips of cells

and dividing factors stored in a ROM. The cell voltages are monitored for the battery low (PLV)

protection, battery exhausted (PEV) and charge control. As the pack voltage is lower than the PLV, the

SS4003 will enable the battery low control output through the Batt_Low pin for secondary battery pack

protection. Exhausting charge threshold levels are used to determine when the battery has reached a

pre-programmed “empty” state. If a validate discharge period is present, the full charge capacity will

update at this point. Four pre-programmed voltage thresholds, PCV, PBV, PPV and PMV, are used to

determine the charge state. When the pack voltage is lower than the PCV, the charge control is in the

trickle charge mode. In the trickle charge mode, the charge current is controlled at a level below 0.2C.

The charge control will enter the pre-defined constant current charge mode if the pack voltage is higher

than the PCV. The cell balance function activates after the pack voltage reach the PBV and keep in

active state until both cells voltage are over PBV. As the pack voltage goes higher than the PPV, the

charge mode transits from constant current to constant voltage charge mode. Through the whole charge

period, the SS4003 continues monitor the individual cell voltage and keep both cell voltages not larger

than the PMV (predefined cell maximum voltage).

Cell Balancing

The SS4003 also provides the cell balance function. Passive type of cell balance technologies is

implemented in SS4003. The cell balance control output pin controlled the current bypass path during

the charge period. The cell balance function is activate when one of the cell voltage over the pack

balance start voltage (PBV). The cell balance function will turn off when both of the cell voltages are

over the PBV.

Battery Management Data Selections

The SS4003 reserves 4 sets of battery information that can be selected by pin S1 and pin S2. If S1 and

S2 inputs both are grounded, the first set will be used. The set information include: Full-charge capacity

(FCCAP), Voltage at 50% of FCCAP, Pack maximum voltage, End-discharge voltage (3% of FCCAP),

charge taper current, charge current, and trickle- charge current etc. Battery data could be sent to SSC

in advance, and SSC could program the customer specified data sets.