Chapter2 Operating Principles

Rev. A 2-31

2.2.2.8 CR Motor Drive Circuit
In the CR motor, the same UPD2917(IC14) as the PF motor has used. In the IC, Bi-pola drive PWM
current control type is performed, m aking it possible to provide stable current to each phase of motor.
Also, it makes possible to change over the ref erence voltage as drive current setti ngs by making 3
combinations(100%, 66% and 33%), using 4 current setting ports(i nput). (Refer to 2.1.1.3 for mot or and
details about sequence) In the carriage motor, firm ware supports the micro-step driving in the S t ylus Color
600. The figure below shows carriage motor drive circuit.
Unlike using Uni-Pola drive, ther e i s no cable for GND in the motor since Bi-P ol a drive is performed in the
CR motor.(Refer to section 2.1.1.2 since carriage m otor interior connection diagram has the sam e
connection as the PF motor’s phase connection. This hel ps to under stand t he reason why the direction of
current is controlled freely in each phase by the c om binations of high/low control signals.
The current control is performed by output por t (60•`67 / 70•`71 pin) of E05B43(IC2), its outer resistance
circuit and driver IC14(UDN2917). Fi rst, 10 resistance which are connected to the output port of t he gat e
array divide each current val ues of phase A and B in the CR motor.
The firmware possesses 16 different ways of current val ues individually as current table out of
combinations made by 5 resistance which are connected to the out put ports(46•`49 pin) in the gate array.
On the other hand, signals which are output by combinati on of these resistance’s on/off are input
independently in the 25 and 44 pins. HIC is driven at the different standard voltage f or each phase A and B.
Actual on/off control to send electri city through the motor is perform ed by t he process that SEN1 and
SEN2 terminals (2 and 13 pin) detect the input signal from the gate array which is monitored by t he
interior comparator, confirm t he c ur r ent that actually flew the phase as current val ue again and
perform the feed back to the on/off . (Refer to before page since it is same as the one of PF motor)
A
PFA
PF/A
PFB
PF/B
3
21
I10
I11
I20
I21
2
1
23
24
Vref1
Vref2
SENS1
E1
SENS2
E2
CRA0
CRA1
CRB0
CRB1
75
76
72
73
77
74
CRAPH
CRBPH
43
26
PH1
PH2
MTBV0-V4
MTAV0-V4
44
25
1
2
3
4
/A
/B
B
4
5
Current Selection
Resistor
E05B43(IC2) UDN2917(IC14)
Figure 2-29. Carriage Motor Circuit Block Diagram