Computer having a function of detecting a low-battery state

Claim 3

The apparatus according to claim 1, charac­terized in that said comparing means includes means (18) for indicating the low-battery state of the battery when it is determined that the output voltage from the bat­tery is lower than the reference voltage.

Claim 4

The apparatus according to claim 2, charac­terized in that said reference voltage setting means includes means for changing the reference voltage in accordance with the temperature, so that said indication of the low-battery state is performed a predetermined time before the voltage of the battery reaches a prede­termined operation enable voltage value.

Claim 5

The apparatus according to claim 1, charac­terized in that said temperature detecting means (15) detects the temperature of the battery.

Claim 6

The apparatus according to claim 1, charac­terized in that said reference voltage setting means comprises means (11) for finding the reference voltage in accordance with the output current of the battery, and correcting means (11) for correcting the found reference voltage in accordance with the temperature and obtaining a final reference voltage.

Claim 7

The apparatus according to claim 5, charac­terized in that said correcting means includes memory means (112) for storing correction voltages corre­sponding to various temperatures, means (111) for reading out the correction voltage from the memory means (112) in response to the detected temperature, and means (111) for correcting the reference voltage in accordance with the read-out correction voltage.

Claim 8

The apparatus according to claim 1, charac­terized in that said reference voltage setting means includes memory means (112) for storing the reference voltage predetermined in accordance with the temperature and output current of the battery, and means (111) for selectively reading out the reference voltage from the memory means (112) in accordance with the detected temperature and the output current from the battery.

Claim 9

The apparatus according to claim 1, charac­terized in that said reference voltage setting means includes at least one of means (111, 112) for setting a higher reference voltage in accordance with the increase in temperature, when the current value is constant, and means (111, 112) for setting a higher reference voltage in accordance with the decrease in current value, when the temperature is constant.

Claim 10

A computer apparatus having a function of determining whether or not a battery, serving as a driving power source, is in a low-battery state, said apparatus comprising: battery means (12) for serving as a power source for the computer apparatus; data processing means (14) for receiving power from the battery means and processing data; current value detecting means (17) for detecting the current value of a current output from the battery means; temperature detecting means (15) for detecting temperature; reference voltage setting means (111) for setting a reference voltage in accordance with the current value detected by said current value detecting means and the temperature detected by said temperature detecting means; comparing means (111) for comparing an output voltage from the battery means (12) with said reference voltage; and means (18) for indicating that the battery means is in the low-battery state, when said comparing means determines that the output voltage from the battery means is lower than said reference voltage.

Claim 11

A computer apparatus having a function of determining whether or not a battery, serving as a driving power source, is in a low-battery state, said apparatus comprising: battery means (12) for serving as a power source for the computer apparatus; data processing means (14) for receiving power from the battery means and processing data; current value detecting means (17) for detecting the current value of a current output from the battery means; temperature detecting means (15) for detecting temperature; reference voltage setting means (111) for setting a reference voltage in accordance with the current value detected by said current value detecting means and the temperature detected by said temperature detecting means; comparing means (111) for comparing an output voltage from the battery means (12) with said reference voltage; and means (18) for indicating that the battery means is in the low-battery state, when said comparing means determines that the output voltage from the battery means is lower than said reference voltage.

Claim 12

The apparatus according to claim 9, charac­terized in that said reference voltage setting means includes means (111, 112) for setting a higher reference voltage in accordance with the increase in temperature, when the current value is constant.

Claim 13

The apparatus according to claim 9, charac­terized in that said reference voltage setting means includes means (111, 112) for setting a higher reference voltage in accordance with the decrease in current value, when the temperature is constant.

Claim 14

The apparatus according to claim 9, charac­terized in that said temperature detecting means inclu­des means for measuring the temperature of the battery means (12).

Claim 15

The apparatus according to claim 9, charac­terized in that said reference voltage setting means includes means for setting the reference voltage in accordance with the temperature, so that said indication of the low-battery state by said indicating means (18) is performed a predetermined time before the output voltage of the battery means (12) reaches a voltage (VA) at which the operation of the data processing means becomes unstable.

Claim 16

The apparatus according to claim 9, charac­terized in that said reference voltage setting means comprises means (11) for finding the reference voltage in accordance with the output current of the battery means, and correcting means (11) for correcting the found reference voltage in accordance with the tem­perature and obtaining a final reference voltage.

Claim 17

The apparatus according to claim 14, charac­terized in that said correcting means includes memory means (112) for storing correction voltages corresponding to various temperatures, means (111) for reading out the correction voltage from the memory means (112) in response to the detected temperature, and means (111) for correcting the reference voltage in accordance with the read-out correction voltage.

Claim 18

The apparatus according to claim 9, charac­terized in that said reference voltage setting means includes memory means (112) for storing the reference voltage predetermined in accordance with the temperature and output current of the battery, and means (111) for selectively reading out the reference voltage from the memory means (112) in accordance with the detected temperature and the output current from the battery.

Claim 19

The apparatus according to claim 9, charac­terized in that said computer apparatus is a portable computer.

Claim 22

The method according to claim 18, characterized in that said reference voltage setting step comprises: a step of finding a first point in time (TC) at which a characteristic curve representing a variation of a battery voltage with the passage of time, when temperature is a predetermined degree (0°C) and a current has a predetermined value (600 mA), reaches a predetermined operation enable voltage value (VA); a step of finding a second point in time (TB) which precedes the first point in time (TC) by a predetermined time; a step of finding reference voltages (VB2, VB3) for desired output currents (200, 400 mA), on the basis of battery voltages (VB2, VB3) given by characteristic curves for the desired output currents (200, 400 mA) at the second point in time (TB) at the predetermined temperature (0°C); and a correction step (11) of correcting the found reference voltages (VB2, VB3) in accordance with the temperature, thereby obtaining final reference voltages.

Claim 23

The method according to claim 19, characterized in that said correcting step comprises: a step of finding a third point in time (TCn) at which the characteristic curve of the battery, which corresponds to the predetermined output voltage (600 mA) and a desired temperature, reaches a the predetermined operation enable voltage value (VA); a step of determining a fourth point in time (TTn) which precedes the third point in time (TC) by said predetermined time; a step of finding a voltage defined by said charac­teristic curve at the fourth point in time; a step of finding a difference between said found voltage and said reference voltage for each of specific temperatures; and a step of adding said difference in voltage to said reference voltage, on the basis of detected temperature and current value.