| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a load drive system for preventing false detection of load disconnection, discriminating between disconnection and a short circuit of both ends of a drive transistor, and detecting them. <P>SOLUTION: When a control circuit 10 is driven by a low side system by controlling FET 3 on the basis of output voltage of a differential amplifier circuit 9 which differentially amplifies both ends of a load 2, a first comparator 11 compares drain voltage Vd of the load 2 and the FET 3 with first threshold voltage V1 lower than a full on voltage of the FET 3, while a second comparator 12 compares the drain voltage Vd with second threshold voltage V2 higher than non-inverse input terminal voltage V+ of an operational amplifier 6 comprising a differential amplifier circuit 7. An AND gate 16 detects disconnection when the drain voltage Vd is over the first threshold voltage V1 and is below the second threshold voltage V2 during a period when the FET 3 is turned off by a transistor 17; and an AND gate 15 detects a ground fault when the drain voltage Vd is below both the first and second threshold voltages V1 and V2. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
