| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To normally control the luminance of an LED 105 even if a voltage of a power supply 301 becomes high. <P>SOLUTION: A voltage of a VOUT terminal 106 is designed to be higher than that of a VIN terminal 109 in a circuit. Thus, when a voltage of a voltage source 101 becomes high and the voltage of the VIN terminal 109 also becomes high, the voltage of the VOUT terminal 106 also becomes high by that amount. Therefore, even if the voltage of the VIN terminal 109 becomes high, a switching regulator control circuit 108 can always increase the voltage of the VIN terminal 109 normally. As a result, a voltage of an FB terminal 104 can be controlled normally and a current of the LED 105 and a resistance 103 is also controlled normally, thereby normally controlling the luminance of the LED 105. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
