Service manual

Principles of Operation
Constant current drive circuit
The carriage motor drive current is given by the following equation:
When the carriage stops, CPU port PB5 is set to HIGH, the input to the chopping
circuit becomes 0 V, and current is applied from the +5 V line to the motor via
resistance Rl and diode Dl. This current is given by the following equation:
Figure 2-35 shows the constant current control circuit. Table 2-4 lists the current
values for the reference voltages.
2-36
Figure 2-35. Constant Current Control Circuit
LQ-200/AP3000