| 摘要 |
An electronically commutated motor has at least two winding phases (112, 114) which are wound together or otherwise inductively coupled. Current in each phase is controlled by a respective power transistor (124, 128). An integrated circuit controller (146) receives signals from a Hall sensor (118) and generates rotor position output signals (OUT1, OUT2) which are oppositely phased and are applied to the bases of the respective power transistors (124, 128) so that the power transistors never both conduct at the same time. Further, a pair of latching transistors (162, 172) and a pair of base drain resistors (164, 174), connected to respective bases of the power transistors (124, 128) are provided, in order to assure "soft" switching of the power transistors at low RPM, yet prompter switching and higher efficiency at high RPM. These additional components also ensure a sufficiently long current gap between switch-off of one power transistor and switch-on of the other power transistor.
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