Charge controlling circuit, charge controlling method, and electronic device provided with same charge controlling circuit

• US 20060082346A1
• Filed: 10/18/2005
• Published: 04/20/2006
• Est. Priority Date: 10/18/2004
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Nagasawa, Makoto
• Granted Patent: US 7,541,780 B2
• Time in Patent Office: Days
• US Class Current: 320/150
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/007192 in response to temperature

Abstract

A charge controlling circuit is provided in which a temperature of a main body of a portable cellular phone or an ambient temperature thereof is detected by a temperature sensor and, when the temperature is higher than or equal to an lower limit in a proper temperature range required by the secondary battery and is lower than a specified reference value, a charging current having a first current value is fed to the secondary battery and, when the temperature is lower than or equal to an upper limit in a proper temperature range required by the secondary battery and is higher than or equal to the specified reference value, a charging current having a second current value being less than the first current value is fed to the secondary battery. When the temperature is a value outside of a proper temperature range required by the secondary battery, the charging to the secondary battery is stopped.

Claims

1. A charge controlling circuit employed in an electronic device to perform specified operations using a mounted secondary battery as a power source and to control a charging current to be supplied to said secondary battery, wherein a temperature of a main body of said electronic device or an ambient temperature thereof is detected and, when said temperature is higher than or equal to an lower limit in a proper temperature range required by said secondary battery and is lower than a specified reference value, a charging current having a first current value is fed to said secondary battery and, when said temperature is lower than or equal to an upper limit in said proper temperature range required by said secondary battery and is higher than or equal to said specified reference value, a charging current having a second current value being less than said first current value is fed to said secondary battery and, when said temperature is a value outside of said proper temperature range, charging of said secondary battery is stopped.

2. The charge controlling circuit according to claim 1, comprising:

a temperature detecting unit to detect a temperature of a main body of said electronic device or an ambient temperature thereof and to output a temperature detecting voltage corresponding to the detected temperature;

a level judging unit to output an active-mode judging signal when said temperature detecting voltage is a value corresponding to a temperature within said proper temperature range and a non-active mode judging signal when said temperature detecting voltage is not a value corresponding to said temperature within said proper temperature range;

a charge controlling unit to feed a charging current set by using supply power supplied from an external power source to said secondary battery when said judging signal is in an active mode and to stop supply of said charging current when said judging signal is in a non-active mode; and

a charging current setting unit to set said charging current at said first current value when said temperature detecting voltage is a value corresponding to a temperature being higher than or equal to a lower limit value within said proper temperature range and being lower than said specified reference value and to set said charging current at said second current value when said temperature detecting voltage is a value corresponding to a temperature being lower than or equal to an upper limit value within said proper temperature range and being higher than or equal to said reference value.

3. The charge controlling circuit according to claim 1, wherein said reference value is set at a value being near to an upper limit within said proper temperature range.

8. The charge controlling circuit according to claim 1, comprising:

a temperature detecting means to detect a temperature of a main body of said electronic device or an ambient temperature thereof and to output a temperature detecting voltage corresponding to the detected temperature;

a level judging means to output an active-mode judging signal when said temperature detecting voltage is a value corresponding to a temperature within said proper temperature range and a non-active mode judging signal when said temperature detecting voltage is not a value corresponding to said temperature within said proper temperature range;

a charge controlling means to feed a charging current set by using supply power supplied from an external power source to said secondary battery when said judging signal is in an active mode and to stop supply of said charging current when said judging signal is in a non-active mode; and

a charging current setting means to set said charging current at said first current value when said temperature detecting voltage is a value corresponding to a temperature being higher than or equal to a lower limit value within said proper temperature range and being lower than said specified reference value and to set said charging current at said second current value when said temperature detecting voltage is a value corresponding to a temperature being lower than or equal to an upper limit value within said proper temperature range and being higher than or equal to said reference value.

4. A charge controlling method applied to an electronic device to perform specified operations using a mounted secondary battery as a power source and to control a charging current to be supplied to said secondary battery, wherein a temperature of a main body of said electronic device or an ambient temperature thereof is detected and, when said temperature is higher than or equal to an lower limit in a proper temperature range required by said secondary battery and is lower than a specified reference value, a charging current having a first current value is fed to said secondary battery and, when said temperature is lower than or equal to an upper limit in a proper temperature range required by the secondary battery and is higher than or equal to said specified reference value, a charging current having a second current value being less than said first current value is fed to said secondary battery and, when said temperature is a value outside of said proper temperature range, charging of said secondary battery is stopped.

5. An electronic device to perform specified operations using a mounted secondary battery as a power source comprising:

a charge controlling circuit to detect a temperature of a main body of said electronic device or an ambient temperature thereof and to feed a charging current having a first current value to said secondary battery when said temperature is higher than or equal to a lower limit in a proper temperature range required by said secondary battery and is lower than a specified reference value and to feed a charging current having a second current value being less than said first current value to said secondary battery when said temperature is lower than or equal to an upper limit in said proper temperature range required by said secondary battery and is higher than or equal to said specified reference value, and to stop charging of said secondary battery when said temperature is a value outside of said proper temperature range.

6. The electronic device according to claim 5, wherein said charge controlling circuit comprises;

a temperature detecting unit to detect a temperature of a main body of said electronic device or an ambient temperature thereof and to output a temperature detecting voltage corresponding to the detected temperature;

a level judging unit to output an active-mode judging signal when said temperature detecting voltage is a value corresponding to a temperature within said proper temperature range and a non-active mode judging signal when said temperature detecting voltage is not a value corresponding to said temperature within said proper temperature range;

a charge controlling unit to feed a charging current set by using supply power supplied from an external power source device to said secondary battery when said judging signal is in an active mode and to stop supply of said charging current to said secondary battery when said judging signal is in a non-active mode; and

a charging current setting unit to set said charging current at said first current value when said temperature detecting voltage is a value corresponding to a temperature being higher than or equal to a lower limit value within said proper temperature range and being lower than said specified reference value and to set said charging current at said second current value when said temperature detecting voltage is a value corresponding to a temperature being lower than or equal to an upper limit value within said proper temperature range and being higher than or equal to said reference value.

7. The charge controlling circuit according to claim 5, wherein said reference value is set at a value being near to an upper limit within said proper temperature range.

9. The electronic device according to claim 5, wherein said charge controlling circuit comprises;

a temperature detecting means to detect a temperature of a main body of said electronic device or an ambient temperature thereof and to output a temperature detecting voltage corresponding to the detected temperature;

a level judging means to output an active-mode judging signal when said temperature detecting voltage is a value corresponding to a temperature within said proper temperature range and a non-active mode judging signal when said temperature detecting voltage is not a value corresponding to said temperature within said proper temperature range;

a charge controlling means to feed a charging current set by using supply power supplied from an external power source device to said secondary battery when said judging signal is in an active mode and to stop supply of said charging current to said secondary battery when said judging signal is in a non-active mode; and

a charging current setting means to set said charging current at said first current value when said temperature detecting voltage is a value corresponding to a temperature being higher than or equal to a lower limit value within said proper temperature range and being lower than said specified reference value and to set said charging current at said second current value when said temperature detecting voltage is a value corresponding to a temperature being lower than or equal to an upper limit value within said proper temperature range and being higher than or equal to said reference value.