| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a short circuit protective circuit which can be manufactured by the same semiconductor manufacturing process as with the manufacture of constant-voltage regulators for positive voltage. SOLUTION: As a load current increases, voltage drop in a second resistor 9 is increased. When the voltage exceeds the threshold voltage of a fourth N-channel enhancement CMOS transistor 4, the fourth N-channel enhancement CMOS transistor 4 is brought into conduction. Accordingly, a first P-channel enhancement CMOS transistor 5 is brought into conduction, and further a second N-channel enhancement CMOS transistor 2 is brought into conduction. As a result, the gate potential of an output transistor 1 is held at negative voltage VSS, and the output transistor 1 is brought out of conduction. Therefore, any excessive output current is not passed through, and short circuit protection is provided.</p> |
