UC1635
UC2635
UC3635
Phase Locked Frequency Controller
FEATURES
DESCRIPTION
•
Precision Phase Locked Frequency
The UC1635 family of integrated circuits was designed for use in preci-
sion speed control of DC motors. An extension to the UC1633 line of
phase locked controllers, these devices provide access to both of the
digital phase detector’s inputs, and include a reference frequency di-
vider output pin. With this added flexibility, this family of controllers can
be used to obtain phase synchronization of multiple motors.
Control System
•
•
Crystal Oscillator
Programmable Reference Frequency
Dividers
•
•
•
Phase Detector with Absolute Frequency
Steering
A reference frequency can be generated using the device’s crystal oscil-
lator and programmable dividers. The oscillator operates using a broad
range of crystals, or, can function as a buffer stage to an external fre-
quency source.
Separate Divider Outputs and Phase
Detector Input Pins
Double Edge Option on the Frequency
Feedback Sensing Amplifier
The phase detector responds proportionally to the phase error between
the detector’s minus input pin and the sense amplifier output. This
phase detector includes absolute frequency steering to provide maxi-
mum drive signals when any frequency error exists. This feature allows
optimum start-up and lock times to be realized.
•
•
Two High Current Op Amps
5V Reference Output
Two op-amps are included that can be configured to provide necessary
loop filtering. The outputs of these op-amps will source or sink in excess
of 16mA, so they can provide a low impedance control signal to driving
circuits.
Additional features include a double edge option on the sense amplifier
that can be used to double the loop reference frequency for increased
loop bandwidths. A 5V reference output can be used to accurately set
DC operating levels.
BLOCK DIAGRAM
UDG-92019
7/97