A new control IC for switched reluctance motor drives

A new control IC for switched reluctance motor drives is described. The LMB1008 contains all the necessary analog and digital control to drive a switched reluctance motor in both forward and reverse rotation with stepwise-adjustable firing angles. Both motoring and braking modes are provided. The internal commutation logic can operate with shaft position signals derived from either 3 or 2 Hall or optical sensors; or in 'straight-through' mode with no shaft position sensors. For closed-loop speed control an internal tacho (frequency-to-voltage converter), oscillator, error amplifier, and PWM generator are provided. A comparator is also provided for excess current detection and current limiting. The IC is implemented in National Semiconductor's BLOCCS process technology. Supply voltage range is 7-24 V and the supply current is 20 mA. The IC has an internal regulated voltage level of 5 V, and the input voltage levels are TTL-compatible (with pull-up for open-collector drives). The authors include typical performance data a waveforms.<
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