Control circuit and method for driving a half-bridge circuit
First Claim
1. A method of controlling a circuit comprising:
- providing a first transistor connected to a second transistor, wherein the first transistor and second transistor each include a control input;
switching off the second transistor and comparing a drive characteristic at the control input of the second transistor with a first threshold value and a second threshold value;
switching on the first transistor following a first time period, wherein the first time period begins when the drive characteristic at the control input of the second transistor is equal to the first threshold value; and
determining the first threshold value based on a second time period.
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Abstract
A method is disclosed for controlling a first transistor in a half-bridge circuit which also includes a second transistor. The transistors can be controlled by applying drive voltages to their gates. During a switch-off operation of the second transistor, the amplitude of the drive voltage of the second transistor is compared with a first threshold value and a second threshold value. A switch-on operation for the first transistor is started following a specified first period which begins at a first time when the drive voltage of the second transistor undershoots the first threshold value. The first threshold value is set in accordance with a second period which begins at a second time when the amplitude of the drive voltage of the second transistor undershoots the second threshold value. The second period ends at another time when the first transistor adopts a specified initial operating state during the switch-on operation.
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Citations
21 Claims
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1. A method of controlling a circuit comprising:
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providing a first transistor connected to a second transistor, wherein the first transistor and second transistor each include a control input;
switching off the second transistor and comparing a drive characteristic at the control input of the second transistor with a first threshold value and a second threshold value;
switching on the first transistor following a first time period, wherein the first time period begins when the drive characteristic at the control input of the second transistor is equal to the first threshold value; and
determining the first threshold value based on a second time period. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for controlling a first transistor and a second transistor, wherein the first transistor and the second transistor each comprise a load path and a control gate, wherein the load path of the first transistor is connected in series with the load path of the second transistor, and wherein the first transistor can be controlled by applying a first drive voltage to the control gate of the first transistor and the second transistor can be controlled by applying a second drive voltage to the control gate of the second transistor, the method comprising:
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during a switch-off operation of the second transistor, comparing the amplitude of the second drive voltage with a first threshold value and a second threshold value;
starting a switch-on operation for the first transistor following a specified first period, wherein the specified first period begins at a first time, wherein the first time is when the second drive voltage undershoots the first threshold value; and
setting the first threshold value in accordance with a second period, wherein the second period begins at a second time and ends at an end time, wherein the second time is when the amplitude of the second drive voltage undershoots the second threshold value, and wherein the end time is when the first transistor adopts a specified initial operating state during the switch-on operation. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A control circuit configured to generate a control signal for a first transistor in a half-bridge circuit comprising the first transistor and a second transistor, the control circuit comprising:
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a first input configured to receive a first operating state signal for the first transistor;
a second input configured to receive a second operating state signal for the second transistor;
a first comparator configured to compare the second operating state signal with a first threshold value and provide an enabling signal intended to enable the generation of a switch-on level of the control signal following a time delay; and
a threshold value generating circuit configured receive the first operating state signal and the first operating state signal and generate the first threshold value. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification