FAULT DETECTION FOR BATTERY CHARGERS

• US 20090273872A1
• Filed: 05/01/2008
• Published: 11/05/2009
• Est. Priority Date: 05/01/2008
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Cordes, Kevin, Riechel, Patrick, Rivalsi, Kenneth J., Paul, Christopher R.
• Granted Patent: US 7,848,072 B2
• Time in Patent Office: Days
• US Class Current: 361/93.100
• CPC Class Codes: G01R 1/203 Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: H02J 7/00304 Overcurrent protection

Abstract

A method of fault detection for battery chargers includes sensing a charge current applied to a battery with a resistive element. The method includes measuring a voltage across the resistive element. The method includes generating a trigger signal when the measured voltage across the resistive element exceeds a predetermined value. The method includes generating from the trigger signal an interrupt signal for a microprocessor. The method includes initiating an over-current handling routine in the microprocessor.

Claims

1. A method comprising:

sensing a charge current applied to a battery with a resistive element;

measuring a voltage across the resistive element;

generating a trigger signal when the measured voltage across the resistive element exceeds a predetermined value;

generating from the trigger signal an interrupt signal for a microprocessor; and

initiating an over-current handling routine in the microprocessor.

2. The method of claim 1, wherein the measuring a voltage across the resistive element comprising:

measuring a voltage across the resistive element with a comparator.

3. The method of claim 1, wherein the measuring a voltage across the resistive element comprising:

measuring a voltage across the resistive element with a differential amplifier.

4. The method of claim 1, wherein the measuring a voltage across the resistive element comprising:

filtering the voltage across the resistive element with a low pass filter.

5. The method of claim 1, wherein the sensing a charge current applied to a battery with a resistive element comprising:

passing the charge current through the resistive element.

6. A method comprising:

sensing a charge current applied to a battery with a resistive element;

measuring a voltage across the resistive element;

generating a trigger signal when the measured voltage across the resistive element exceeds a predetermined value;

coupling the trigger signal to a data bus that is configured to be polled by a microprocessor; and

initiating an over-current handling routine in the microprocessor.

7. The method of claim 6, wherein the measuring a voltage across the resistive element comprising:

measuring a voltage across the resistive element with a comparator.

8. The method of claim 6, wherein the measuring a voltage across the resistive element comprising:

filtering the voltage across the resistive element with a low pass filter.

9. The method of claim 6, wherein the sensing a charge current applied to a battery with a resistive element comprising:

passing the charge current through the resistive element.

10. An apparatus comprising:

a battery charging station;

a resistive element coupled to the battery charging station for sensing a charge current generated by the battery charging station;

a comparator having a first input coupled to a first terminal of the resistive element and having a second input coupled to a second terminal of the resistive element, and wherein the first terminal of the comparator is coupled to a reference voltage; and

a microprocessor having an interrupt input coupled to an output of the comparator.

11. The apparatus of claim 10, further comprising:

a battery charging station having a first terminal coupled to a power source and a second terminal coupled to a common voltage through the resistive element.

12. The apparatus of claim 10, further comprising:

a battery charging station having a first terminal coupled to a power source through the resistive element and a second terminal coupled to a common voltage.

13. The apparatus of claim 10, wherein the comparator is a Schmidt trigger.

14. The apparatus of claim 10, wherein the comparator is a differential amplifier.

15. The apparatus of claim 10, further comprising:

a capacitive element coupled between the second terminal of the comparator and a common voltage.

16. The apparatus of claim 10, further comprising:

a low-pass filter coupled between the second terminal of the resistive element and the second input of the comparator.

17. An apparatus comprising:

a plurality of battery charging stations;

a plurality of resistive elements wherein a resistive element is coupled to a battery charging station for sensing a charge current generated by the battery charging station;

a plurality of comparators wherein a given comparator is associated with a corresponding resistive element selected from the plurality of resistive elements, the given comparator has a first input coupled to a first terminal of the corresponding resistive element and has a second input coupled to a second terminal of the corresponding resistive element, and wherein the first terminal of the given comparator is coupled to a reference voltage;

a microprocessor having an interrupt input; and

wherein the plurality of comparators includes multiple comparators each having an output coupled to the interrupt input of the microprocessor.

18. An apparatus comprising:

a plurality of battery charging stations;

a plurality of resistive elements wherein a resistive element is coupled to a battery charging station for sensing a charge current generated by the battery charging station;

a plurality of comparators wherein a given comparator is associated with a corresponding resistive element selected from the plurality of resistive elements, the given comparator has a first input coupled to a first terminal of the corresponding resistive element and has a second input coupled to a second terminal of the corresponding resistive element, and wherein the first terminal of the given comparator is coupled to a reference voltage;

a microprocessor;

a data bus that is configured to be polled by the microprocessor; and

wherein the plurality of comparators includes multiple comparators each having an output coupled to the data bus.