| 摘要 |
<P>PROBLEM TO BE SOLVED: To dispense with an external power supply for generating a gate voltage for a MOSFET operating with a grounded gate for protecting a low voltage MOSFET. <P>SOLUTION: A level generation circuit includes: a constant current generation section for generating a first current of a constant magnitude from a first supply voltage; a first current mirror circuit section comprising a first thin film NMOSFET and a second thin film NMOSFET and outputting a second current proportional to the first current; a protection circuit section comprising a third thin film NMOSFET and a first thick film PMOSFET used with a grounded gate for protecting the second thin film NMOSFET, a first diode for preventing a backflow of current to the first power supply, and a second diode for preventing a gate-source voltage of the third thin film NMOSFET from becoming negative; a second current mirror circuit section for outputting a third current proportional to the second current; and a first Zener diode section for generating a first constant voltage from the third current. <P>COPYRIGHT: (C)2013,JPO&INPIT |
