| 摘要 |
<p>PURPOSE: To reduce a dark current flowing to an externally mounted switch by interposing a reverse flow prevention diode to a non-power supply line side of a pull-up resistor. CONSTITUTION: Reverse flow prevention diodes 64-66 are interposed between switches 53-55 and 2nd pull-up resistors 61-63 in a switch input circuit turned off in the sleep mode and turned on in the wakeup mode by a control circuit. Through the presence of the reverse flow prevention diodes 64-66, it is prevented that a current flowing to the 1st pull-up resistors 56-58 flows to the 2nd pull-up resistors 61-63. Furthermore, the resistance of each of the 2nd pull-up resistors 61-63 is selected to be sufficiently smaller than that of the 1st pull-up resistors 56-58. Thus, the entire circuit is led surely to the sleep state with simple configuration.</p> |
