Patent ID: 7583060

Claim:
A protective circuit for a secondary battery pack comprising a first bank to be charged or discharged and having cells coupled in series and in parallel, and a second bank to be charged or discharged and coupled in series to the first bank and having a plurality of cells coupled in series and in parallel, the protective circuit comprising: a first controller for sensing a charging or discharging voltage of the first bank and outputting a first controller output voltage if overcharging or over-discharging is sensed; a second controller for sensing a charging or discharging voltage of the second bank and outputting a second controller output voltage if overcharging or over-discharging is sensed; a level shifter for adjusting the second controller output voltage to an adjusted voltage output having about a same voltage level as the first controller output voltage; a first switch adapted to be toggled on/off in response to the first controller output voltage or the adjusted voltage output from the level shifter; and a second switch coupled with a large-current line for charging or discharging each of the first bank and the second bank, and adapted to be toggled on/off to stop the charging or discharging of the first bank and the second bank in accordance with whether the first switch is toggled on/off.