Service manual

Operating Principles
Rev. A
2-2
3
2.3.2.4 PF Motor Driver Circuit
The PF motor for this printer operates the following:
Paper loading
Paper feeding
Pumping
The gate array E05B33 (IC6) outputs the phase drive control signals (PFAPH and PFBPH), phase data
(PFA0/1 and PPFB1/0) and voltage reference data (PFV) to the driver IC UDN2917EB (IC16). The driver
IC then controls the phase current based on the voltage reference data. This sequence enables the micro
step with a minimum of 1/720 inch at 2-2 phase.
B
A
E05B33
(IC6)
UDN2917EB
(IC16)
PF Motor
PFA0
PFA1
PFB0
PFB1
PFAPH
PFBPH
VREF1
VREF2
44
25
45
46
47
48
50
PFV
PF A
PF_A
PF B
PF_B
A
B
6
3
18
21
I10
I11
I20
I21
PH1
PH2
2
1
23
24
43
26
+5V
49
PO0
PO1
PO2
PO3
33
34
35
36
Figure 2-23. PF Motor Driver Circuit Block Diagram