Granted Patent B2

US 7,940,059 · App. 12/198,104 · Granted May 10, 2011

Abstract

Claims (28)

1. A method for measuring an on resistance in an H-bridge including first and second transistors connected to a first output terminal, third and fourth transistors connected to a second output terminal, and a measurement switch connected between the first and second output terminals, in which the first and third transistors are connected to a first power supply terminal, and the second and fourth transistors are connected to a second power supply terminal, the method comprising:

supplying the first transistor with measurement current during a first period;

measuring a first voltage at the first power supply terminal via the third transistor using the second output terminal during the first period;

measuring a second voltage at the first output terminal via the measurement switch using the second output terminal during the first period; and

determining the on resistance of the first transistor based on the measurement current, the first voltage, and the second voltage.

2. The method for measuring an on resistance in an H-bridge of claim 1 , further comprising:

connecting a voltmeter between the second output terminal and the second power supply terminal to measure the first voltage and second voltage with the voltmeter.

3. The method for measuring an on resistance in an H-bridge of claim 1 , further comprising:

supplying the second transistor with the measurement current during a second period;

measuring a third voltage at the first power supply terminal via the fourth transistor using the second output terminal during the second period;

measuring a fourth voltage at the first output terminal via the measurement switch using the second output terminal during the second period; and

determining the on resistance of the second transistor based on the measurement current, the third voltage, and the fourth voltage.

4. The method for measuring an on resistance in an H-bridge of claim 3 , further comprising:

connecting a voltmeter between the second output terminal and the second power supply terminal to measure the first voltage, second voltage, third voltage, and fourth voltage with the voltmeter.

5. The method for measuring an on resistance in an H-bridge of claim 1 , further comprising:

supplying the third transistor with the measurement current during a third period;

measuring a fifth voltage at the first power supply terminal via the first transistor using the first output terminal during the third period;

measuring a sixth voltage at the second output terminal via the measurement switch using the first output terminal during the third period; and

determining the on resistance of the third transistor based on the measurement current, the fifth voltage, and the sixth voltage.

6. The method for measuring an on resistance in an H-bridge of claim 5 , further comprising:

connecting a voltmeter between the first output terminal and the second power supply terminal to measure the fifth voltage and sixth voltage with the voltmeter.

7. The method for measuring an on resistance in an H-bridge of claim 1 , further comprising:

supplying the fourth transistor with the measurement current during a fourth period;

measuring a seventh voltage at the second power supply terminal via the second transistor using the first output terminal during the fourth period;

measuring an eighth voltage at the second output terminal via the measurement switch using the first output terminal during the fourth period; and

determining the on resistance of the fourth transistor based on the measurement current, the seventh voltage, and the eighth voltage.

8. The method for measuring an on resistance in an H-bridge of claim 7 , further comprising:

connecting a voltmeter between the first output terminal and the second power supply terminal to measure the seventh voltage and eighth voltage with the voltmeter.

Assignments (29)