| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately perform the adjustment of output light quantity of a CIS by extending the adjustment range of the output level of the CIS. <P>SOLUTION: CIS_CLK being a system clock and CIS_SH for deciding charge storage time are supplied to the CIS 101, and the charge storage time of the CIS 101 is controlled by changing the cycle of the CIS_SH. A PWM control signal is supplied to a TH adjustment circuit 106. The TH adjustment circuit 106 has an integrating circuit, generates DC voltage from the PWM control signal and supplies comparative reference voltage to a comparator 102. The comparative reference voltage of the comparator 102 is adjusted by changing the duty of the PWM control signal. Then, LED_PWM is supplied to an LED current control circuit 108. In action by an LED_PWM signal, the LED_PWM signal being a pulse signal is made constant voltage by the integrating circuit, and the duty of the pulse signal is changed, thereby performing the adjustment of light quantity. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
