Method and apparatus for communication between an electronic device and a connected battery

• US 6,809,649 B1
• Filed: 01/26/1999
• Issued: 10/26/2004
• Est. Priority Date: 01/26/1999
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wendelrup, Heino, Hansson, Magnus
• Primary Examiner(s): GOINS, DAVETTA WOODS
• Application Number:
  US09/238,007
• Time in Patent Office: 2,100 Days
• Field of Search: 340/636, 340/634, 340/346, 340/395, 340/692, 340/636.1, 340/636.11, 340/636.12, 340/636.18, 340/636.21, 320/112, 320/106, 320/120, 320/107, 320/132, 320/134, 320/136, 324/430, 455/426, 455/456, 455/572, 455/573
• US Class Current: 340/636.1
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00038 using passive battery identification means, e.g. resistors or capacitors identification by mechanical connections H02J7/0045
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An apparatus supporting both identification of a battery type and communications over an interface between a battery and an electronic device is disclosed. The electronic device includes a processor for communicating with communications circuitry of the battery. Identification circuitry associated with the processor enables a determination of the type of battery with which the electronic device is connected. If a “smart” battery capable of carrying out serial communications with the electronic device is connected, the electronic device further provides means for carrying out communications between the processor and the communication circuitry of the battery.

Claims

1. An apparatus supporting both battery identification and communications over between a battery and an electronic device, comprising:

a three-pin interface for connecting the battery and the electronic device and the battery, said three-pin interface comprising;

first and second pins for interconnecting power between the electronic device and the battery;

a third pin for providing serial communications between the electronic device and the battery;

a first circuitry within the electronic device capable of communicating with the battery through the three-pin interface;

means for identifying a type of the battery connected to the electronic device; and

means enabling communications between the first circuitry and communications circuitry within the battery through the three-pin interface.

2. The apparatus of claim 1, wherein the serial communications comprise half duplex, asynchronous communications.

3. The apparatus of claim 1, wherein the means for enabling communications, comprises:

a transceiver for transmitting and receiving serial communications between the electronic device and the communications circuitry of the battery;

first means for holding data to be transmitted by the transceiver; and

second means for holding data received by the transceiver.

4. The apparatus of claim 3, wherein the transceiver comprises a universal asynchronous transmitter receiver.

5. The apparatus of claim 3, wherein the first and second means for holding comprise data registers.

6. The apparatus of claim 1 wherein a bit rate between the processor and communications circuitry of the battery is no greater than 1200 baud.

7. The apparatus of claim 1, wherein the means for identifying comprises means for determining at least one of a resistance, capacitance, or short circuit located in the battery, the resistance or capacitance identifying the type of the battery.

8. The apparatus of claim 7, wherein the means for determining comprises:

a resistor connected within the electronic device; and

means associated with the processor for calculating a resistance in the battery in response to a resistance value of the resister connected within the electronic device and a voltage drop across the resistor.

9. The apparatus of claim 7, wherein the means for determining comprises:

a capacitor connected within the electronic device; and

means associated with the processor for calculating a capacitance in the battery pack in response to a capacitance value of the capacitor connected within the electronic device and a voltage drop across the capacitor.

10. The apparatus of claim 7, wherein the means for determining comprises:

a current source within the electronic device for generating a current; and

means associated with the processor for calculating the resistance in the battery in response to current provided by the current source and a voltage level at a communication pin interface.

11. The apparatus of claim 1, wherein the battery includes:

a first memory for storing a representation of a total capacity of the battery pack; and

a second memory for storing a representation of the current capacity of the battery, such that means associated with the electronic device may calculate the present charge level of the battery in response to the representations in the first and second memories.

12. A method enabling both battery identification and serial communication over an interface between a battery and an electronic device, comprising the steps of:

selectively switching a current source between system voltage and a communications pin in the electronic device in response to an active connection between the battery and the electronic device; and

determining an impedance between a communications pin and a ground pin within the battery in response to a current supplied by the current source and the voltage level at the communications pin;

determining whether the battery has communications capabilities and a type of the battery based on the impedance.

13. The method of claim 12 further including the step of enabling communications between the electronic device and the battery upon determining that the battery has communications capabilities.

14. The method of claim 13 wherein the step of enabling communications further comprises the steps of:

placing data to be transmitted to the battery into a first data register;

transmitting the data in the first data register to the battery via the communications pin;

.

receiving data from the battery via the communications pin;

placing the received data from the battery into a second data register; and

reading the received data within the second data register.

15. The method of claim 12 wherein the step of measuring further includes the steps of:

selectively switching an impedance between system voltage and the communications pin;

determining the impedance in response to a value of the resistance between system voltage and the single communication pin, a voltage level at the communications pin and the system voltage level.

17. The method of claim 12, further including the step of attempting to communicate with the battery from the electronic device prior to the step of selectively switching.

16. A method enabling both battery identification and communication over an interface between a battery and an electronic device, comprising the steps of:

attempting to communicate with the battery from the electronic device via a serial connection responsive to a connection between the battery and the electronic device;

selectively switching a current source in the electronic device between system voltage and a communications pin if the electronic device may not communicate with the battery; and

determining a first resistance value in the battery responsive to a current value provided by the current source.