| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the number of bits of an analog-digital converter when precise current detection is required in discrete ranges. <P>SOLUTION: A current detection circuit 10 includes: a first resistive element 12 having a small resistance value for current detection in a high current range; a low current detection section 20 for current detection in a low current range; a switching section 14 for switching a current path between the high current range and the low current range; buffer amplifier sections 30, 32; analog-digital conversion circuit sections 40, 42; and a switching control circuit 34 for outputting a switching signal to the switching section 14. The low current detection section 20 includes: a second resistive element 28 having a large resistance value for current detection in the low current range; a bypass transistor 26; and an operational amplifier 24 for controlling a voltage across the second resistive element 28 to a reference voltage 22 serving as a threshold voltage. <P>COPYRIGHT: (C)2012,JPO&INPIT |
