Semiconductor device for protecting secondary battery, battery pack, and electronic device using same

A battery pack comprising:

• a secondary battery;
• a discharge-control transistor;
• a charge-control transistor connected in series with the discharge-control transistor between a negative power source terminal of the secondary battery and either a terminal of a load or a negative power source terminal of a charger;
• and
• a battery protection semiconductor device for protecting the secondary battery,
• the battery protection semiconductor device comprising:
• a detection circuit to detect at least one of an excessively charged state, an excessive discharging state an overcurrent state, a short-circuit state and an overheating state of the secondary battery;
• a control circuit to turn on and off the discharge-control transistor and the charge-control transistor;
• and
• a charge prevention circuit to prevent the secondary battery from being charged by turning off the charge-control transistor when a voltage of the secondary battery is not greater than a predetermined low-voltage criterial voltage that is variable by trimming a portion of the charge prevention circuit,
• wherein the charge prevention circuit comprises:
• a first inverter circuit that receives a high-level signal during a charging mode, connected to both the negative power source terminal and a positive power source terminal of the secondary battery;
• and
• a second inverter circuit that receives an output from the first inverter circuit, connected to both the negative power source terminal and a positive power source terminal of the charger, and
• wherein an input threshold voltage of the second inverter circuit is variable by trimming a portion of the second inverter circuit, and the charge-control transistor is turned off according to an output from the second inverter circuit when the voltage of the secondary battery is not greater than the low-voltage criterial voltage.

A battery protection semiconductor device for protecting a secondary battery,

• the battery protection semiconductor device comprising:
• a detection circuit to detect at least one of an excessively charged state, an excessive discharging state, an overcurrent state, a short-circuit state, and an overheating state of the secondary battery;
• a control circuit to turn on and off the discharge-control transistor and the charge-control transistor;
• and
• a charge prevention circuit to prevent the secondary battery from being charged by turning off the charge control transistor when a voltage of the secondary battery is not greater than a predetermined low-voltage criteria voltage that is variable by trimming a portion of the charge prevention circuit.