Portable computer and docking station having charging circuits with remote power sensing capabilities

• US 6,888,338 B1
• Filed: 01/27/2003
• Issued: 05/03/2005
• Est. Priority Date: 01/27/2003
• Status: Expired due to Fees

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Bucur, Constantin, Popescu-Stanesti, Vlad
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US10/351,927
• Time in Patent Office: 827 Days
• Field of Search: 320/103, 320/107, 320/112, 320/113, 320/114, 320/115, 320/127, 320/137, 363/21.07, 363/21.08, 363/21.09, 363/97
• US Class Current: 320/137
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence

Abstract

A charging circuit system includes: a power supply; a sensor configured to sense a power level of the power supply and provide a first signal representative of the power level; and a charging circuit including: at least one input signal terminal and at least one output signal terminal; and a transmitter including an amplifier, wherein the amplifier has an input coupled to at least one input signal terminal, and the amplifier has an output coupled to at least one output signal terminal, wherein at least one input signal terminal is configured to receive the first signal from the sensor, and wherein the amplifier is configured to amplify the first signal and provide a second signal. The charging circuit system may be used by a charging circuit of a laptop computer in conjunction with a docking station.

Claims

1. A charging circuit system comprising:

a power supply;

a sensor configured to sense a power level of said power supply and provide a first signal representative of said power level; and

a charging circuit comprising;

at least one input signal terminal and at least one output signal terminal; and

a transmitter comprising an amplifier, said amplifier having an input coupled to said at least one input signal terminal, and said amplifier having an output coupled to said at least one output signal terminal, wherein said at least one input signal terminal is configured to receive said first signal from said sensor, and wherein said amplifier is configured to amplify said first signal and provide a second signal, wherein said sensor comprises a current sensor, and wherein said second signal is a voltage signal, and said transmitter further comprises a conversion circuit configured to convert said second signal to a third signal proportionate to said second signal, wherein said third signal is a current signal.

2. The system of claim 1, wherein said conversion circuit comprises a conversion circuit amplifier configured to receive said second signal from said amplifier and provide an output to a transistor, wherein a first electrode of said transistor is coupled to said at least one output signal terminal.

3. The charger of claim 1, wherein said transistor is a PMOS transistor and said first electrode is a drain electrode.

4. The charger of claim 2, wherein said transistor in an NMOS transistor and said first electrode is a source electrode.

5. A charging circuit system comprising:

a first power supply;

a sensor configured to sense a power level of said first power supply and provide a first signal representative of said power level;

a transmitter configured to accept said first signal and transmit a second signal representative of said power level;

a charging circuit comprising;

a receiver configured to receive said second signal;

a current allocation circuit coupled to said receiver, said current allocation circuit configured to provide a control signal to maximize a charging current to an associated battery while maintaining a supply current from said first power supply within a maximum current rating of said first power supply; and

an error amplifier configured to provide said control signal based on said second signal;

a second power supply; and

said receiver further comprising a summation circuit and an input amplifier, wherein said summation circuit comprises a first summation input terminal and second summation input terminal, wherein said first summation input terminal is coupled to a first input signal terminal for receiving said second signal, and said second summation input terminal is coupled to an output of said input amplifier, wherein said input amplifier is configured to receive an input signal representative of a power level of said second power supply, and wherein an output of said summation circuit is coupled to said error amplifier.

6. A charging circuit system comprising:

a first power supply;

a sensor configured to sense a power level of said first power supply and provide a first signal representative of said power level;

a transmitter configured to accept said first signal and transmit a second signal representative of said power level, wherein said second signal is a voltage signal;

a charging circuit comprising;

a receiver configured to receive said second signal;

a current allocation circuit coupled to said receiver, said current allocation circuit configured to provide a control signal to maximize a charging current to an associated battery while maintaining a supply current from said first power supply within a maximum current rating of said first power supply;

a second power supply; and

said receiver further comprising an error amplifier, a summation circuit, and an input amplifier, wherein said summation circuit comprises a first summation input terminal and second summation input terminal, wherein said first summation input terminal is coupled to a first input signal terminal of said charging circuit for receiving said second signal, and said second summation input terminal is coupled to an output of said input amplifier, wherein said input amplifier is configured to receive an input signal representative of a power level of said second power supply, and wherein an output of said summation circuit is coupled to said error amplifier, said error amplifier configured to provide an output control signal based on said output of said summation circuit.

7. A charging circuit system comprising:

a first power supply;

a sensor configured to sense a power level of said first power supply and provide a first signal representative of said power level;

a transmitter configured to accept said first signal and transmit a second signal representative of said power level, wherein said second signal is a current signal;

a charging circuit comprising;

a receiver configured to receive said second signal;

a current allocation circuit coupled to said receiver, said current allocation circuit configured to provide a control signal to maximize a charging current to an associated battery while maintaining a supply current from said first power supply within a maximum current rating of said first power supply;

a second power supply; and

said receiver further comprising an error amplifier, a summation circuit, and an input amplifier, wherein said summation circuit comprises a first summation input terminal and second summation input terminal, wherein said first summation input terminal is coupled to a first input signal terminal of said charging circuit for receiving said second signal and a conversion resistor for providing a voltage drop across said conversion resistor in proportion to said second signal, and said second summation input terminal is coupled to an output of said input amplifier, wherein said input amplifier is configured to receive an input signal representative of a power level of said second power supply, and wherein an output of said summation circuit is coupled to said error amplifier, said error amplifier configured to provide an output control signal based on said output of said summation circuit.

8. A docking station for a laptop computer comprising:

a docking power supply;

a docking sensor configured to sense a power level of said docking power supply and provide a first signal representative of said power level; and

a docking charging circuit comprising;

at least one input signal terminal and at least one output signal terminal; and

a transmitter comprising an amplifier, said amplifier having an input coupled to said at least one input signal terminal, and said amplifier having an output coupled to said at least one output signal terminal, wherein said at least one input signal terminal is configured to receive said first signal from said docking sensor, and wherein said amplifier is configured to amplify said first signal and provide a second signal;

wherein said second signal is a voltage signal, and said transmitter further comprises a convention circuit configured to convert said second signal to a third signal proportionate to said second signal, wherein said third signal is a current signal.

9. The docking station of claim 8, wherein said conversion circuit comprises a conversion circuit amplifier configured to receive said second signal from said amplifier and provide an output to a transistor, wherein a first electrode of said transistor is coupled to said at least one output signal terminal.

10. The docking station of claim 8, wherein said transistor is a PMOS transistor and said first electrode is a drain electrode.

11. The docking station of claim 8, wherein said transistor is an NMOS transistor and said first electrode is a source electrode.

12. A laptop computer system comprising:

an input device;

a processor;

an output device;

a battery;

a remote power supply;

a laptop charging circuit configured to provide a charging current to said battery and to receive supply current from said remote power supply, said laptop charging circuit comprising;

a receiver configured to receive a first signal representative of said supply current from said remote power supply;

a current allocation circuit coupled to said receiver, said current allocation circuit configured to provide a control signal configured to maximize said charging current to said battery while maintaining said supply current from said remote power supply within a maximum current rating of said remote power supply; and

an error amplifier configured to provide said control signal based on said first signal;

a laptop power supply; and

said receiver further comprising a summation circuit and an input amplifier, wherein said summation circuit comprises a first summation input terminal and second summation input terminal, wherein said first summation input terminal is coupled to a first input signal terminal for receiving said first signal and said second summation input terminal is coupled to an output of said input amplifier, wherein said input amplifier is configured to receive an input signal representative of a power level of said laptop power supply, and wherein an output of said summation circuit is coupled to said error amplifier.

13. A laptop computer system comprising:

an input device;

a processor;

an output device;

a battery;

a remote power supply;

a laptop charging circuit configured to provide a charging current to said battery and to receive supply current from said remote power supply;

said laptop charging circuit comprising;

a receiver configured to receive a first signal representative of said supply current from said remote power supply, wherein said first signal is a voltage signal; and

a current allocation circuit coupled to said receiver, said current allocation circuit configured to provide a control signal configured to maximize said charging current to said battery while maintaining said supply current from said remote power supply within a maximum current rating of said remote power supply;

a laptop power supply; and

said receiver further comprising an error amplifier, a summation circuit, and an input amplifier, wherein said summation circuit comprises a first summation input terminal and second summation input terminal, wherein said first summation input terminal is coupled to a first input signal terminal of said charging circuit for receiving said first signal, and said second summation input terminal is coupled to an output of said input amplifier, wherein said input amplifier is configured to receive an input signal representative of a power level of said laptop power supply, and wherein an output of said summation circuit is coupled to said error amplifier, said error amplifier configured to provide said control signal based on said output of said summation circuit.

14. A laptop computer system comprising:

an input device;

a processor;

an output device

a battery;

a remote power supply;

a laptop charging circuit configured to provide a charging current to said battery and to receive supply current from said remote power supply, said laptop charging circuit comprising;

a receiver configured to receive a first signal representative of said supply current from said remote power supply, wherein said first signal is a current signal; and

a current allocation circuit coupled to said receiver, said current allocation circuit configured to provide a control signal configured to maximize said charging current to said battery while maintaining said supply current from said remote power supply within a maximum current rating of said remote power supply;

a laptop power supply; and

said receiver further comprising an error amplifier, a summation circuit, and an input amplifier, wherein said summation circuit comprises a first summation input terminal and second summation input terminal, wherein said first summation input terminal is coupled to a first input terminal of said charging circuit for receiving said first signal and a conversion resistor for providing a voltage drop across said conversion resistor in proportion to said first signal, and said second summation input terminal is coupled to an output of said input amplifier, wherein said input amplifier is configured to receive an input signal representative of a power level of said laptop power supply, and wherein an output of said summation circuit is coupled to said error amplifier, said error amplifier configured to provide said control signal based on said output of said summation circuit.