Method of over current and over voltage protection of a power switch in combination with regulated DI/DT and DV/DT
AssigneeInfineon Technologies Austria AG
InventorsKarl Norling, Johannes Groeger, Anton Mauder, Bernhard Wicht
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Abstract
A method for protecting a power switch during turn-on includes sensing that a change in current through the power switch is in regulation, measuring a time the change in current through the power switch is in regulation, and comparing the time the change in current through the power switch is in regulation to a reference time. An over current signal, which can be used to disable the power switch, is generated if the time the change in current through the power switch is in excess of the reference time.
Claims20
A method for protecting a power switch comprising:
- interrogating whether or not a pulse width modulation (PWM) signal to the power switch is active, and, if an active PWM signal is undetected;
- regulating a change in voltage across the power switch during a mode of operation of the power switch, such that the change in voltage across the power switch is limited to a predetermined non-zero rate of change during the mode of operation of the power switch;
- sensing that the change in voltage across the power switch is in regulation;
- measuring a time the change in voltage across the power switch is in regulation only during the mode of operation of the power switch;
- and
- comparing the time the change in voltage across the power switch is in regulation to a reference time.
A method for protecting a power switch during a turn-off condition of the power switch, the method comprising:
- interrogating whether or not a pulse width modulation (PWM) signal to the power switch is active, and, if an active PWM signal is undetected;
- regulating a change in voltage across the power switch during a mode of operation of the power switch, such that the change in voltage across the power switch is limited to a predetermined non-zero rate of change during the mode of operation of the power switch;
- sensing that the change in voltage across the power switch is above a reference change in voltage value;
- measuring a time the change in voltage across the power switch is above the reference change in voltage value only during the mode of operation of the power switch;
- and
- comparing the time the change in voltage across the power switch is above the change in voltage value to a reference time.
A method for protecting a power switch comprising:
- interrogating whether or not a pulse width modulation (PWM) signal to the power switch is active, and, if an active PWM signal is undetected;
- regulating a change in voltage across the power switch during a mode of operation of the power switch, such that the change in voltage across the power switch is limited to a predetermined non-zero rate of change during the mode of operation of the power switch;
- sensing that the change in voltage across the power switch is in regulation;
- measuring a time the change in voltage across the power switch is in regulation only during the mode of operation of the power switch;
- comparing the time the change in voltage across the power switch is in regulation to a reference time;
- generating a plurality of overvoltage signals when the time the change in voltage across the power switch is in regulation is in excess of the reference time;
- and
- monitoring the plurality of overvoltage signals with a counter.
Dependencies are inferred from the claim text.