| 摘要 |
<p>PURPOSE: To obtain a DC/DC converter outputting a plurality of signals for generating more than one type of DC output voltage by stopping the charging of an inductor when the output voltage from a voltage regulator exceeds a predetermined level otherwise charging a capacitor according to a switching signal. CONSTITUTION: When the difference VB-VA of a voltage component VB and a switching signal VA is larger than 2VBE (threshold voltage of transistors Q3, Q4), two transistors Q3, Q4 are turned on otherwise they are turned off. Consequently, if VB-VA is higher than 2VBE and two transistors Q3, Q4 connected through Darlington connection are turned on, on/off operation of a transistor Q2 is controlled by an inverted switching signal VA. When the Q2 is turned on, a power supply signal VCC is delivered to an inductor L which turns a diode D instantaneously and a capacitor C is charged with a voltage including a supply voltage from the inductor L and the power supply signal VCC.</p> |
