Battery charger with temperature control

• US 7,777,454 B2
• Filed: 10/06/2009
• Issued: 08/17/2010
• Est. Priority Date: 12/08/2006
• Status: Active Grant

• Current Assignee: Monolithic Power Systems Incorporated
• Original Assignee: Monolithic Power Systems Incorporated
• Inventors: Zhang, Zhengwei
• Primary Examiner(s): Patidar; Jay M
• Assistant Examiner(s): DIAO, M BAYE
• Application Number:
  US12/574,209
• Publication Number:
  US 20100090658A1
• Time in Patent Office: 315 Days
• Field of Search: 320/137, 320/152, 320/164
• US Class Current: 320/152
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

A battery charger integrated circuit with temperature control is disclosed that includes a temperature sensor circuit and a charging current generator circuit. Upon receiving a temperature reading voltage (VDT), the temperature sensing circuit is operable to generate a second reference voltage (VREF) that is a function of the first reference voltage (VREF1). The charging current generator circuit generates and continuously adjusts a reference current (I1) and a charging current (IOUT) according to the second reference voltage (VREF). Whenever the temperature reading voltage (VDT) exceeds the first reference voltage, the temperature sensor circuit is operable to adjust the second reference voltage (VREF).

Claims

1. A battery charger integrated circuit comprising:

a temperature sensor circuit, electrically coupled to receive a first reference signal and a temperature signal, operable to generate a second reference signal that is related to the first reference signal, wherein when the temperature signal is greater than the first reference signal, a logic output signal is generated to adjust the second reference signal; and

a charging current generator circuit, electrically coupled to receive the second reference signal, operable to generate a charging current based on the second reference signal and a reference current, wherein the charging current is reduced when the temperature signal is greater than the first reference signal such that a charging die is prevented from exceeding a predetermined temperature.

2. The battery charger integrated circuit of claim 1, wherein the first reference signal is a current signal or a voltage signal and the second reference signal is a current signal or a voltage signal.

3. The battery charger integrated circuit of claim 1, wherein the temperature signal is a current signal or a voltage signal.

4. The battery charger integrated circuit of claim 1, wherein the charging current is linearly proportional to the second reference signal and the reference current.

5. A method of providing temperature control in a battery charger integrated circuit, comprising:

receiving a temperature signal indicating a temperature measurement of the battery charger integrated circuit;

comparing the temperature signal to a first reference signal to generate a logic output signal when the temperature signal is greater than the first reference signal;

generating a second reference signal related to the first reference signal and the logic output signal; and

generating a charging current based on the second reference signal and a reference current, wherein the charging current is reduced when the temperature signal is greater than the first reference signal such that a charging die is prevented from exceeding a predetermined temperature.

6. The battery charger integrated circuit of claim 5, wherein the first reference signal is a current signal or a voltage signal and the second reference signal is a current signal or a voltage signal.

7. The battery charger integrated circuit of claim 5, wherein the temperature signal is a current signal or a voltage signal.

8. The battery charger integrated circuit of claim 5, wherein the charging current is linearly proportional to the second reference signal and the reference current.

9. A battery charger integrated circuit comprising:

a temperature sensor circuit, electrically coupled to receive a first reference signal and a temperature signal, operable to generate a second reference signal that is related to the first reference signal and a logic output signal;

means for generating the logic output signal when the temperature signal is greater than the first reference signal, and

means for adjusting a charging current based on the second reference signal and a reference current, such that a charging die is prevented from exceeding a predetermined temperature.

10. The battery charger integrated circuit of claim 9, wherein the first reference signal is a current signal or a voltage signal and the second reference signal is a current signal or a voltage signal.

11. The battery charger integrated circuit of claim 9, wherein the temperature signal is a current signal or a voltage signal.

12. The battery charger integrated circuit of claim 9, wherein the charging current is linearly proportional to the second reference signal and the reference current.