| 摘要 |
An H-Bridge motor controller having a floating, electrically isolated high side FET driver design where the motor driver circuity is electrically isolated from the logic circuitry. Back EMF generation during motor operation is minimized by employing a "fifth" power transistor to the H-Bridge that connects the motor coil to ground when the other transistors in the H-Bridge are turned off, so as to provide a direct path for the unused energy to be removed from the driver circuit without interfering with the normal switching of the FETs. Alternatively, back EMF generation is minimized by applying switching signals to the H-Bridge where, instead of turning the low side FET drivers between motor clocks, the low side FET drivers are both turned on during the "off time" period, so as to connect both ends of the motor coil to ground during the "off" period, thereby draining the coil of unused energy. The fifth power transistor also permits either one-half or the entire motor coil to be connected to the H-Bridge at the commencement of the energizing phase, thereby altering the inductive load seen by the H-Bridge upon motor energization. The motor controller also includes analog and digital circuits that automatically vary the voltage and/or current applied to the motor depending upon performance characteristics such as speed, electromagnetic characteristics and torque load.
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