Line powered modem

• US 6,212,274 B1
• Filed: 11/12/1997
• Issued: 04/03/2001
• Est. Priority Date: 06/26/1997
• Status: Expired due to Fees

• Current Assignee: Data Race, Inc.
• Original Assignee: Data Race, Inc.
• Inventors: Ninh, Winston
• Primary Examiner(s): Isen, Forester W.
• Assistant Examiner(s): PENDLETON, BRIAN T
• Application Number:
  US08/968,956
• Time in Patent Office: 1,238 Days
• Field of Search: 379/413, 379/93.36, 379/102.04, 379/93.28, 375/222
• US Class Current: 379/413
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 19/08 with current supply sources at the substations generating ringing current H04M19/04

Abstract

A battery powered computer system includes an add-on device, such as a modem, with a power supply that uses power from a telephone line to provide power to the modem. In one embodiment the power supply is an adaptive power supply that uses power from both the telephone line and the battery of the computer system. The adaptive power supply determines the maximum power available from the telephone line and delivers that power to the modem. If the power from the telephone line is not sufficient for the modem, the adaptive power supply supplements the power with the power from the computer system. In one embodiment, the adaptive power supply uses power time division multiplexing to share the power from the telephone line and the computer system.

Claims

1. A modem coupled to a telephone line and a system power supply, comprising:

a digital signal processor coupled to said telephone line and configured to send and receive data from said telephone line; and

an adaptive power supply coupled to said telephone line and said system power supply, wherein said adaptive power supply is configured to use power from said telephone line and said system power supply to provide a voltage output signal that provides power to said digital signal processor;

wherein said adaptive power supply is configured to determine a maximum amount of power available from said telephone line, to convert said maximum amount of power to a voltage output signal compatible with said digital signal processor, and to provide power from said system power supply to supplement said power from said telephone line if needed.

2. The modem of claim 1 wherein said adaptive power supply is configured to measure voltage characteristics of said telephone line to determine said maximum amount of power available from said telephone line.

3. The modem of claim 1 wherein said adaptive power supply is configured to measure current characteristics of said telephone line to determine said maximum amount of power available from said telephone line.

4. A modem coupled to a telephone line and a system power supply, comprising:

a digital signal processor coupled to said telephone line and configured to send and receive data from said telephone line; and

an adaptive power supply coupled to said telephone line and said system power supply, wherein said adaptive power supply is configured to use power from said telephone line and said system power supply to provide a voltage output signal that provides power to said digital signal processor;

wherein said adaptive power supply is configured to use power time division multiplexing to share said power from said telephone line and said power from said system power supply.

5. A modem coupled to a telephone line and a system power supply, comprising:

a digital signal processor coupled to said telephone line and configured to send and receive data from said telephone line; and

an adaptive power supply coupled to said telephone line and said system power supply, wherein said adaptive power supply is configured to use power from said telephone line and said system power supply to provide a voltage output signal that provides power to said digital signal processor;

wherein said adaptive power supply is configured to calculate a power ratio of power available from said telephone line versus power required by said digital signal processor, wherein said adaptive power supply is configured to draw power from said telephone line for a portion of a power cycle and to draw power from said system power supply for a remaining portion of said power cycle, wherein said portion of said power cycle is determined by said power ratio.

6. A method of delivering power to a computer system coupled to a power source and a telephone line comprising:

determining an amount of power available from said telephone line;

determining an amount of power required by said computer system and a residual amount of power that exceeds said amount of power available from said telephone line;

delivering said amount of power available from said telephone line to said computer system;

delivering said residual power from said power source to said computer system.

7. The method of delivering power to a computer system of claim 6 wherein said power source is a battery of said computer system.

8. The method of delivering power to a computer system of claim 6 wherein determining said amount of power available from said telephone line comprises measuring characteristics of the telephone line.

9. The method of delivering power to a computer system of claim 8 further comprising adjusting an input impedance to match an impedance of said telephone line.

10. The method of delivering power to a computer system of claim 6 further comprising determining a power ratio of said power required by said computer system versus said power available from said telephone line.

11. The method of delivering power to a computer system of claim 10 wherein power is delivered to said computer system from said telephone line for a first portion of a power cycle and power is delivered to said computer system from said power source for a second portion of said power cycle, wherein a length of said first portion and a length of said second portion of said power cycle depend on said power ratio.

12. The method of delivering power to a computer system of claim 6 wherein said power from said telephone line provides power to a modem of said computer system.

13. A method of delivering power from two sources to a load comprising:

determining a power ratio, wherein said power ratio defines a first portion of said power to be delivered from a first power source and a second portion of said power to be delivered from a second power source;

defining a power cycle, wherein said power cycle is a time period during which said first power source and said second power source deliver a portion of said power;

dividing said power cycle into a first portion and a second portion wherein a length of said first portion and said second portion are dependent upon said power ratio;

delivering power to said load from said first source during said first portion of said power cycle; and

delivering power to said load from said second source during said second portion of said power cycle.

14. The method of delivering power to claim 13 wherein said power ratio is a ratio of a maximum amount of power available from said telephone line versus an amount of power required by said load.

15. The method of delivering power of claim 13 wherein said first power source is a battery and said second power source is a telephone line.

16. A modem card, comprising:

a modem configured to couple to a computer and to a telephone line to transmit and receive data; and

an adaptive power supply configured to coupled to said computer, to said modem, and to said telephone line, wherein said adaptive power supply is configured to combine power from said computer system and said telephone line on a single voltage signal to supply power to said modem;

wherein said adaptive power supply is configured to determine a ratio of maximum power available from said telephone line to power required by said modem, and draw power from said telephone line and from said computer system according to said ratio to supply power to said modem.

17. A modem card, comprising:

a modem configured to couple to a computer and to a telephone line to transmit and receive data; and

an adaptive power supply configured to coupled to said computer, to said modem, and to said telephone line, wherein said adaptive power supply is configured to combine power from said computer system and said telephone line on a single voltage signal to supply power to said modem;

wherein said adaptive power supply is configured to combine power from said computer system and said telephone line by time division multiplexing.