Secondary battery protection semiconductor device for protecting a secondary battery

A secondary battery protection semiconductor device for protecting a secondary battery,

• wherein the secondary battery protection semiconductor device protects the secondary battery by detecting values of at least plural detection items corresponding to the secondary battery including the detection items of overcharge, overdischarge, charge overcurrent, discharge overcurrent, short-circuit current, and overheat;
• comparing the detected values with corresponding detection levels that are determined beforehand for each of the detection items;
• and based on the comparison results, turning on/off a discharge control transistor and a charge control transistor that are series-connected to the secondary battery,
• wherein:
• among the plural detection items, a first value of a first detection item is detected, and a detection level of a second detection item is changed in accordance with the first value,
• wherein the secondary battery protection semiconductor device comprises a comparator that compares an input voltage with a reference voltage and outputs an overcharge detection signal, a hysteresis voltage being provided at the input voltage;
• wherein the secondary battery protection semiconductor device further comprises:
• an overcharge detection circuit configured to output an overcharge detection signal in response to detecting that a voltage of the secondary battery undergoing a charging operation is at least higher than or equal to a first voltage that is determined beforehand;
• a control circuit configured to turn off the charge control transistor and stop the charging operation of the secondary battery in response to the overcharge detection signal;
• and a temperature detection circuit configured to detect at least one of a temperature of the secondary battery and temperatures of the discharge control transistor and the charge control transistor, wherein:
• the secondary battery protection semiconductor device selects a first mode or a second mode in response to a switching signal;
• in the first mode, in the event that the temperature detected by the temperature detection circuit is higher than or equal to a predetermined temperature, the charge control transistor is turned off and the charging operation of the secondary battery is stopped in response to an output signal of the temperature detection circuit;
• and in the second mode, in the event that the temperature detected by the temperature detection circuit is higher than or equal to the predetermined temperature, the overcharge detection circuit outputs the overcharge detection signal in response to detecting that the voltage of the secondary battery undergoing the charging operation is higher than or equal to a second voltage which is lower than the first voltage, and the charge control transistor is turned off and the charging operation of the secondary battery is stopped in response to the overcharge detection signal;
• and
• wherein the temperatures detected by the temperature detection circuit are given hysteresis.

A secondary battery protection semiconductor device for protecting a secondary battery, comprising:

• an overcharge detection circuit configured to output an overcharge detection signal in response to detecting that a voltage of the secondary battery undergoing a charging operation is at least higher than or equal to a first voltage that is determined beforehand;
• a control circuit configured to stop the charging operation of the secondary battery in response to the overcharge detection signal;
• and
• a temperature detection circuit configured to detect at least one of a temperature of the secondary battery and temperatures of a discharge control transistor and a charge control transistor connected to the secondary battery,
• wherein in the event that the temperature detected by the temperature detection circuit is higher than or equal to a predetermined temperature, the overcharge detection circuit outputs the overcharge detection signal in response to detecting that the voltage of the secondary battery undergoing the charging operation is higher than or equal to a second voltage that is lower than the first voltage, and
• wherein the temperatures detected by the temperature detection circuit are given hysteresis.

A secondary battery protection semiconductor device for protecting a secondary battery, comprising:

• an overcharge detection circuit configured to output an overcharge detection signal in response to detecting that a voltage of the secondary battery undergoing a charging operation is at least higher than or equal to a first voltage that is determined beforehand;
• a control circuit configured to turn off the charge control transistor and stop the charging operation of the secondary battery in response to the overcharge detection signal;
• and
• a temperature detection circuit configured to detect at least one of a temperature of the secondary battery and temperatures of a discharge control transistor and a charge control transistor connected to the secondary battery,
• wherein the secondary battery protection semiconductor device selects a first mode or a second mode in response to a switching signal;
• in the first mode, in the event that the temperature detected by the temperature detection circuit is higher than or equal to a predetermined temperature, the charge control transistor is turned off and the charging operation of the secondary battery is stopped in response to an output signal of the temperature detection circuit;
• and
• in the second mode, in the event that the temperature detected by the temperature detection circuit is higher than or equal to the predetermined temperature, the overcharge detection circuit outputs the overcharge detection signal in response to detecting that the voltage of the secondary battery undergoing the charging operation is higher than or equal to a second voltage which is lower than the first voltage, and the charge control transistor is turned off and the charging operation of the secondary battery is stopped in response to the overcharge detection signal, and
• wherein the temperatures detected by the temperature detection circuit are given hysteresis.