Semiconductor device, battery pack and personal data assistant

A battery pack, comprising:

• an assembled battery which includes a plurality of secondary batteries;
• a first terminal and a second terminal for connecting the assembled battery to an external device;
• a charge control transistor and a discharge control transistor which are connected in series to a power supply path between the first terminal and the assembled battery;
• a sense resistor which is connected in series to a power supply path between the second terminal and the assembled battery;
• and
• a battery control IC that monitors a state of the assembled battery and controls turn-on and turn-off of the charge control transistor and the discharge control transistor,
• wherein the battery control IC includes:
• a voltage measurement unit that measures an output voltage of the assembled battery;
• a current measurement unit that measures a discharging current and a charging current of the assembled battery on a basis of a voltage between both ends of the sense resistor;
• a data processing control unit that generates state information indicating a state of a battery, on a basis of measurement results of the voltage measurement unit and the current measurement unit;
• a current detection unit that detects that a voltage between both ends of the sense resistor exceeds a predetermined threshold voltage;
• and
• a control unit that controls the charge control transistor and the discharge control transistor,
• wherein an output signal from the current detection unit is configured to be input to the voltage measurement unit such that, based on the output signal, the voltage measurement unit and the current measurement unit are able to measure the output voltage and the discharging current in a case that the current detection unit detects that the discharging current exceeds the predetermined threshold, and
• wherein the data processing control unit estimates an internal resistance of the battery on a basis of a voltage measurement value measured by the voltage measurement unit in accordance with the detection performed by the current detection unit and a current measurement value measured by the current measurement unit in accordance with the detection performed by the current detection unit, and calculates an amount of maximum power which is capable of being supplied from the assembled battery on a basis of the estimated value.

A semiconductor device for monitoring a state of a battery, the semiconductor device comprising:

• a voltage measurement unit that measures an output voltage of the battery;
• a current measurement unit that measures a charging current and a discharging current of the battery;
• a data processing control unit that generates state information indicating a state of the battery, on a basis of measurement results of the voltage measurement unit and the current measurement unit;
• and
• a current detection unit that detects that the discharging current exceeds a predetermined threshold, an output signal from the current detection unit is configured to be input to the voltage measurement unit,
• wherein the voltage measurement unit and the current measurement unit have a first measurement mode and a second measurement mode,
• wherein the voltage measurement unit measures the output voltage in the second measurement mode in a case that the current detection unit detects that the discharging current exceeds the predetermined threshold at a time of measuring the output voltage in the first measurement mode,
• wherein the current measurement unit measures the discharging current in the second measurement mode in a case that the current detection unit detects that the discharging current exceeds the predetermined threshold at a time of measuring the discharging current in the first measurement mode, and
• wherein the data processing control unit estimates an internal resistance of the battery on a basis of a first voltage measurement value and a first current measurement value which are measured by the voltage measurement unit and the current measurement unit in the first measurement mode and a second voltage measurement value and a second current measurement value which are measured by the voltage measurement unit and the current measurement unit in the second measurement mode, and calculates an amount of maximum power which is capable of being supplied from the battery on a basis of the estimated value.