| 摘要 |
PROBLEM TO BE SOLVED: To provide an overvoltage/overcurrent protective circuit being proper to a low cost and a miniaturization, reducing the voltage losses of an input and an output, and protecting the circuit from breakdowns due to the overvoltage of an input terminal and the overcurrent of an output terminal. SOLUTION: An overcurrent detecting resistor 1 and a first pnp transistor 2 in which a base is grounded by a bias resistor 3 are connected in series between a power input terminal and an output terminal. When the overvoltage is applied to the power input terminal, an electricity is conducted through a Zener diode 6, a second pnp transistor 7 is turned on and the first pnp transistor 2 is turned off. When the overcurrent is made to flow through the output terminal, the second pnp transistor 7 is turned on and the first pnp transistor 2 is turned off by a voltage generated in the overcurrent detecting resistor 1. COPYRIGHT: (C)2006,JPO&NCIPI
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