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Precision Phase Locked Frequency Control
System
Communication Logic for 2-Phase Motors
Disable Input for Motor Inhibit
Crystal Oscillator
Programmable Reference Frequency Dividers
Phase Detector with Absolute Frequency
Steering
Digital Lock Indicator
Two High Current Op-Amps
5V Reference Output
DESCRIPTION
The UC1634 series of devices is optimized to provide precision
phase locked frequency control for two phase DC brushless mo-
tors. These devices include most of the features of the general
purpose UC1633 Phase Locked Control family and also provide
the out-of-phase commutation signals required for driving two
phase brushless motors. Only an external power booster stage
is required for a complete drive and control system.
The two commutation outputs are open collector devices that can
sink in excess of 16mA. A disable input allows the user to simul-
taneously force both of these outputs to an active low state.
Double edge logic, following the sense amplifier, doubles the ref-
erence frequency at the phase detector by responding to both
edges of the input signal at Pin 7.
BLOCK DIAGRAM
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