| 摘要 |
A detection circuit detects an abnormal current which flows through a first output transistor. In this event, the first output transistor is connected to an external power supply via a load resistor. The above detection circuit mainly includes a second transistor, a constant current supply, a third transistor, a fourth transistor, and a comparator circuit. The constant current supply supplies a constant current into the second transistor. Further, the third transistor is connected to the first output transistor and performs an ON-OFF operation in synchronism with the first output transistor. On the other hand, the fourth transistor is connected to the third transistor in serial and performs the ON-OFF operation opposite to the first output transistor. Moreover, the comparator circuit has a first input and a second input. In this event, a first connection point between the second transistor and the constant current supply is connected to the first input while a second connection point between the third transistor and the fourth transistor is connected to the second input.
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