Power supply system for portable electronic devices

• US 5,986,437 A
• Filed: 12/17/1997
• Issued: 11/16/1999
• Est. Priority Date: 12/17/1996
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Chang-Hum
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): SHIN, KYUNG E
• Application Number:
  US08/992,098
• Time in Patent Office: 699 Days
• Field of Search: 320/161, 320/162, 320/163, 320/125
• US Class Current: 320/162
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• 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

Abstract

A power supply system for a portable device such as portable personal computer, to be operated from a DC power source supplied from a rechargeable battery or an AC adapter includes: an input current detecting circuit for detecting an input current supplied from the AC adapter and for generating a detection signal having a magnitude which varies depending upon the input current, and a charging current control circuit for controlling the amount of the charging current in response to the detection signal. The power supply system has low power losses and effects a high efficiency battery charging.

Claims

1. A system for charging a rechargeable battery used to supply power to a portable device, comprising:

an input terminal for receiving an externally supplied variable amount of input power, the input power including a variable amount of system power for operating said portable device and a variable amount of charging power for charging said battery;

a means for supplying the system power to said portable device;

an output terminal connected to said battery;

a means for supplying a variable amount of charging current flowing through said output terminal to the battery;

a means for detecting an input current flowing through said input terminal and for generating a detection signal having a magnitude which varies depending upon the input current; and

a means for controlling the amount of the charging current in response to the detection signal, said means for controlling the charging current controlling the charging current so as to be constant when the amplitude of the detection signal is less than a predetermined threshold level, and so as to decrease the amount of charging current depending upon the amplitude of the detection signal when the amplitude of the detection signal is not less than the predetermined threshold level.

2. A system for charging a rechargeable battery used to supply power to a portable device, comprising:

an AC adapter for supplying a variable amount of input current including a variable amount of system current for operating said portable device and a variable amount of charging current for charging said battery;

a first current detecting circuit for detecting the amount of charging current and for generating a first detection signal having a magnitude which varies depending upon the charging current;

a second current detecting circuit for detecting the amount of input current and for generating a second detection signal having a magnitude which varies depending upon the input current; and

a charging current control circuit for controlling the amount of the charging current in response to the first and second detection signals, the charging current control circuit including an input terminal connected to said AC adapter, a node for supplying the system current to said portable device and an output terminal connected to said battery, the control circuit controlling the charging current so as to be constant when the amplitude of the second detection signal is less than a predetermined threshold level, and so as to decrease the amount of charging current depending upon the amplitude of the second detection signal when the amplitude of the second detection signal is not less than the predetermined threshold level.

3. The system according to claim 2, said charging current control means comprising a switch element connected between said node and said output terminal, and a switch control circuit for controlling ON/OFF time of said switch element in response to the first and second detection signals.

4. The system according to claim 2, said first current detecting circuit comprising a resistor connected between said node and said output terminal, and an amplifier circuit for amplifying a voltage drop across said resistor in accordance with a predetermined gain and for generating an output signal of the amplified voltage drop as the first detection signal.

5. The system according to claim 2, said second current detecting circuit comprising a resistor connected between said input terminal and said node, and an amplifier circuit for amplifying a voltage drop across said resistor in accordance with a predetermined gain and for generating an output signal of the amplified voltage drop as the second detection signal.

6. A power supply for a portable computer system operable on an internal rechargeable battery, comprising:

an AC adapter for supplying a variable amount of DC power including a variable amount of system power for operating said portable computer system and a variable amount of charging power for charging said battery;

a DC/DC converter for supplying a variety of operating voltages necessary for said system unit using the system power; and

a battery charging circuit for charging said battery using the charging power;

said battery charging circuit comprising;

an input terminal connected to said AC adapter;

an output terminal connected to said battery;

a means for supplying a variable amount of charging current through said output terminal to said battery;

a means for detecting input current flowing from said AC adapter to said input terminal and for generating a detection signal having a magnitude which varies depending upon the input current; and

a means for controlling the amount of the charging current in response to the detection signal, said means for controlling the charging current controlling the charging current so as to be constant when the amplitude of the detection signal is less than a predetermined threshold level, and so as to decrease the amount of charging current depending upon the amplitude of the detection signal when the amplitude of the detection signal is not less than the predetermined threshold level.