DC/DC CONVERTER CIRCUIT AND RS-232 INTERFACE CIRCUIT EMPLOYING SAME

摘要

PURPOSE: To realize serial communication on a voltage defined by S-232 interface communication regulation when two type of voltages are employed individually in the host side circuit. ;CONSTITUTION: Variation of DC input voltage VIN to host side circuit is detected and a voltage boosted at an appropriate rate is created thus obtaining positive and negative DC output voltages VDD, VSS conformable to RS-232 interface communication regulation regardless of variation of power supply voltage. In other words, a voltage Vo2 boosted by a factor of 2 from the voltage of a DC/DC converter circuit is selected for 5V operation whereas a Vo3 boosted by a factor of 3 is selected for 3V operation thus obtaining an DC output voltage.;COPYRIGHT: (C)1993,JPO&Japio