Polarity reversal protection circuit
View Patent ↗A polarity reversal protection circuit includes a MOSFET and a turn-off circuit, which turns off the MOSFET in the case of a polarity reversal. The turn-off circuit includes a detector for detecting the case in which the voltage at the source terminal of the MOSFET undershoots the voltage at the drain terminal of said MOSFET. Furthermore, it includes a quick-break switch for turning off the MOSFET in the event of detected voltage undershooting, a comparator for comparing the voltages present at source terminal and drain terminal of the MOSFET after detected voltage undershooting, wherein the output of the comparator is connected to the gate terminal of the MOSFET, a boost converter, a buck converter and a charge pump for voltage supply, and a switch for switching off the comparator.
1. A polarity reversal protection circuit comprising a MOSFET and a turn-off circuit, characterized in that the turn-off circuit comprises
a detector, a first input of which is connected to a source terminal and a second input of which is connected to a drain terminal of the MOSFET, and an output of which is connected to a switching input of a quick-break switch arranged between the source terminal and a gate terminal of the MOSFET,
a comparator, a first input of which is connected to the source terminal and a second input of which is connected to the drain terminal of the MOSFET, and an output of which is connected to the gate terminal of the MOSFET,
a boost converter, an input of which is connected to the drain terminal of the MOSFET,
a buck converter, an input of which is connected to an output of the boost converter, and an output of which is available for supplying a load, and which has a switching node,
a charge pump, a first input of which is connected to the output of the boost converter and a second input of which is connected to the switching node, and which has a first output connected to the gate terminal of the MOSFET, and
a switch arranged between a supply terminal of the comparator and a second output of the charge pump.
2. The polarity reversal protection circuit as claimed in claim 1 , characterized in that the MOSFET is an N-channel MOSFET.
3. The polarity reversal protection circuit as claimed in claim 1 , characterized in that the switch is connected to a switch-off delay unit.
4. The polarity reversal protection circuit as claimed in claim 1 , characterized in that the quick-break switch ( 3 ) is configured as a resistor (R 12 ).
5. A polarity reversal protection circuit comprising
a MOSFET and
a turn-off circuit, which turns off the MOSFET in a case of a polarity reversal, characterized in that the turn-off circuit comprises
a detector for detecting a case in which a voltage at a source terminal of the MOSFET undershoots a voltage at a drain terminal of said MOSFET,
a quick-break switch for turning off the MOSFET in the event of detected voltage undershooting,
a comparator for comparing the voltages present at the source terminal and the drain terminal of the MOSFET ( 1 ) after detected voltage undershooting, wherein an output of the comparator is connected to a gate terminal of the MOSFET,
a boost converter, a buck converter and a charge pump for voltage supply, and
a switch for switching off the comparator.
6. A device comprising a polarity reversal protection circuit comprising a MOSFET and a turn-off circuit, characterized in that the turn-off circuit comprises
a detector, a first input of which is connected to a source terminal and a second input of which is connected to a drain terminal of the MOSFET, and an output of which is connected to a switching input of a quick-break switch arranged between the source terminal and a gate terminal of the MOSFET,
a comparator, a first input of which is connected to the source terminal and a second input of which is connected to the drain terminal of the MOSFET, and an output of which is connected to the gate terminal of the MOSFET,
a boost converter, an input of which is connected to the drain terminal of the MOSFET,
a buck converter, an input of which is connected to an output of the boost converter, and an output of which is available for supplying a load, and which has a switching node,
a charge pump, a first input of which is connected to the output of the boost converter and a second input of which is connected to the switching node, and which has a first output connected to the gate terminal of the MOSFET, and
a switch arranged between a supply terminal of the comparator and a second output of the charge pump.