ENCAD T-200, Руководство по обслуживанию

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Theory of Operation 2-10
ENCAD T-200 and T-200+ Service Manual
2. Motor current sense
The voltage across a series current sense resistor is measured and
level shifted so that it is centered around 5V.
3. Comparator
This portion divides the output of the reference waveform generator
by two and compares it to the output of the motor current sensor.
Logic inside the gate array generates the control signals for the
power driver that applies voltage across the motor winding in order
to make the actual current match the reference waveform.
4. Power driver
An H-bridge allows the supply voltage to be applied across the
winding in either polarity used to drive the current level to the
desired value.