| 摘要 |
An electric circuit for supplying power to a DC application is disclosed. The electric circuit comprises a DC power source ( 1 ) connectable to an alternator charging circuit ( 2 ), an FET (T 7 ), and a capacitor ( 8 ) connected across the gate terminal and the source terminal of the FET (T 7 ). The drain terminal of the FET (T 7 ) is connected to a negative terminal of the DC source ( 1 ). The FET (T 7 ) protects the circuit against accidental connection of the alternator charging circuit ( 2 ) to the DC power source ( 1 ) with reversed polarity, by opening a switch ( 6 ) of the FET (T 7 ) when this occurs. The capacitor ( 8 ) protects the FET (T 7 ) from being pushed into avalanche in case a load-dump transient occurs. This is because the capacitor ( 8 ) in this case will charge and discharge, thereby introducing a time delay before the switch ( 6 ) is opened. Protection against load-dump transients is thereby obtained by means of a small component with low energy dissipation. Thereby the size of the circuit is reduced and energy is conserved.
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