| 摘要 |
<p>A driver circuit (26) for first and second coils (30a, 30c) includes first and second selector switches (36a, 36c) coupled in series between first terminals (32a, 32c) of the coils (36a, 36c) and a first common junction (38), first and second diodes (44-1, 44-2) coupled in series between second terminals (34a, 34c) of the first and second coils (30a, 30c), respectively, and a second common junction (44) and a source of first potential (46) coupled to the first common junction (38). A modulation switch (56) is coupled between the second common junction (44) and a source of second potential (58). The selector switches (36a, 36c) and modulation switches (56) are operated to cause currents of controlled magnitude to flow through the coils (36a, 36c). The circuit has improved fault immunity whereby at least one coil (36a) can be energized even when another coil (36c) has been subjected to a chassis ground fault.</p> |
