| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power supply for suppressing a transient flow of an excessive output current to supply a constant current and to provide a lighting system equipped with the electric power supply. <P>SOLUTION: In an electric power supply, a collector of a transistor 51 in a regulating part 50 is connected to a plus input port of an operational amplifier 19. When a pulse-width modulation signal is inputted to pulse-width modulation input ports 90 and 91, if the pulse-width modulation signal is a high level, the transistor 51 turns on. A voltage at the input port of the operational amplifier 19 results in V1>Vref, and an output of the operational amplifier 19 becomes a low level. Then, an electric current flows through a photo diode 71, a photo transistor 72 turns on, and a drive signal outputted by an IC 6 becomes a low level. Thus, a transistor 9 and an FET 12 turn off, thereby stopping a switching operation. <P>COPYRIGHT: (C)2012,JPO&INPIT |
