Panasonic KX-MB2110RUW / KX-MB2130RUW / KX-MB2170RUW / KX-MB2117RUB / KX-MB2137RUB / KX-MB2177RUB Service Manual ▷ View online
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KX-MB2110RUW/ KX-MB2130RUW/ KX-MB2170RUW/ KX-MB2117RUB/ KX-MB2137RUB/ KX-MB2177RUB
6.7.2.
Scanner Motor Drive Circuit
General
Scanner motor drive circuit is consist of motor current control circuit ,FB (Flat Bed) motor driver, ADF motor driver and OCP (Over
Current Protection) circuit.
Current Protection) circuit.
6.7.2.1.
Motor current control circuit
1. Function
According to the scan speed, motor current is controlled for appropriate value.
For example, when scan speed is low, motor has enough driving force.
So to prevent the vibration and noise during motor rotation, motor drive current should be reduced.
When scan speed is high, motor needs much driving force. so much current should be supplied.
In order to control the motor current, VREFA and VREFB voltages of IC600 is controlled.
When VREFA and VREFB voltages are high, motor currents are increased, and the voltages are low, motor currents are
reduced.
For example, when scan speed is low, motor has enough driving force.
So to prevent the vibration and noise during motor rotation, motor drive current should be reduced.
When scan speed is high, motor needs much driving force. so much current should be supplied.
In order to control the motor current, VREFA and VREFB voltages of IC600 is controlled.
When VREFA and VREFB voltages are high, motor currents are increased, and the voltages are low, motor currents are
reduced.
In order to control the Vref voltage, PWM pulse is supplied from IC300 pin C23.
PWM pulse is integrated by R601, R604, and C601, then converted to DC voltage.
PWM pulse is integrated by R601, R604, and C601, then converted to DC voltage.
This DC voltage is supplied to Vref pin of each motor drivers.
When duty of PWM pulse is low, Vref voltage is decreased and when duty is high, Vref voltage is increased.
When duty of PWM pulse is low, Vref voltage is decreased and when duty is high, Vref voltage is increased.
For FB motor, motor current is controlled approx. 0.18A-0.3A.
For ADF motor, motor current is controlled approx. 0.30A-0.37A.
For ADF motor, motor current is controlled approx. 0.30A-0.37A.
2. Circuit Diagram
3. Timing chart of current control
Following timing charts are the example of Vref voltage corresponding to PWM pulse duty.
FBMEN
(ADFMEN)
CRM0
CRM1
CRM2
CRM3
CRM4
CRM5
CRM1
CRM2
CRM3
CRM4
CRM5
PWD
IC300
R601
C
601
A
B
R
604
A24
B21
A21
C22
B22
A22
B23
A21
C22
B22
A22
B23
C23
Current control circuit
O.C.P. circuit
VM1, VM2
ENABLE
ENABLE
PHA1
PHB1
IN0
IN1
IN2
IN3
PHB1
IN0
IN1
IN2
IN3
Vref
BOUT2
BOUT1
AOUT2
AOUT1
IC600 (IC700)
1, 15
31
25
26
27
28
29
30
27
28
29
30
19, 20
CN600
(CN701)
3
7
9
13
1
2
3
4
Main Board
FB Motor
(ADF Motor)
24V
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KX-MB2110RUW/ KX-MB2130RUW/ KX-MB2170RUW/ KX-MB2117RUB/ KX-MB2137RUB/ KX-MB2177RUB
6.7.2.2.
O.C.P. (Over Current Protection) circuit
1. Function
If motor driver can supply more than 15 watts, FB and ADF motors may become fire hazards.
To prevent the risk of fire, this circuit is provided.
To prevent the risk of fire, this circuit is provided.
2. Circuit diagram
3. Circuit explanation
When the current supplied from 24V exceeds 0.44A, the voltage between two registers R607 and R608 becomes more than
0.6V (=0.44Ax2.7ohm/2), consequently both Q600, Q601 and Q602 turn on, then "ENABLE" signal (IC600, IC700_pin31)
becomes "Low" level.
When "ENABLE" signal becomes "High" level, FB motor drive block of IC600 is deactivated and currents of FB motor are cut
off.
So the currents which IC600 can supply are limited to less than 0.44A and the wattage is also limited to less than 10.6W
(=0.44Ax24V).
By limiting the wattage less than 15W, risk of fire hazard is eliminated.
0.6V (=0.44Ax2.7ohm/2), consequently both Q600, Q601 and Q602 turn on, then "ENABLE" signal (IC600, IC700_pin31)
becomes "Low" level.
When "ENABLE" signal becomes "High" level, FB motor drive block of IC600 is deactivated and currents of FB motor are cut
off.
So the currents which IC600 can supply are limited to less than 0.44A and the wattage is also limited to less than 10.6W
(=0.44Ax24V).
By limiting the wattage less than 15W, risk of fire hazard is eliminated.
This signal is designed to become "High" when software can not control motors properly by some accidents.
When base of Q602 becomes "High", "ENABLE" signal becomes "Low" and FB motor currents are cut off.
Therefore even in the case of software can not control motors, FB motor stops automatically for securing safety.
ADF motor currents are also cut off by the same method.
When base of Q602 becomes "High", "ENABLE" signal becomes "Low" and FB motor currents are cut off.
Therefore even in the case of software can not control motors, FB motor stops automatically for securing safety.
ADF motor currents are also cut off by the same method.
6.7.2.3.
Motor driver
Motor driver IC600 and IC700 can drive motors up to 0.8A/phase and support up to W1-2 phase excitation.
When "ENABLE" signal (IC600 and IC700_pin31) becomes "L", motor driver is activated.
Stepping pulses are output from IC300 pins A21, A22, B21, B22, B23 and C22.
Frequency and pattern of these pulses determine the motor rotation speed and excitation mode respectively.
Corresponding to these pulses, current are supplied from IC600(IC700)_pin3, pin7, pin9 and pin13 to each motor coils.
When "ENABLE" signal (IC600 and IC700_pin31) becomes "L", motor driver is activated.
Stepping pulses are output from IC300 pins A21, A22, B21, B22, B23 and C22.
Frequency and pattern of these pulses determine the motor rotation speed and excitation mode respectively.
Corresponding to these pulses, current are supplied from IC600(IC700)_pin3, pin7, pin9 and pin13 to each motor coils.
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KX-MB2110RUW/ KX-MB2130RUW/ KX-MB2170RUW/ KX-MB2117RUB/ KX-MB2137RUB/ KX-MB2177RUB
6.8.
Timing chart and wave form of scanner motors
6.8.1.
Drive mode of FB and ADF motor
Correspondent table of operation
44
KX-MB2110RUW/ KX-MB2130RUW/ KX-MB2170RUW/ KX-MB2117RUB/ KX-MB2137RUB/ KX-MB2177RUB
6.8.2.
2 phase excitation
1. Timing chart
2. Wave form
PHA
5V/Div
10V/Div
0.5A/Div
Pin13 of
IC600 or
IC700
IC600 or
IC700
Motor
current
current
Fig. 1
Motor current is changed according to the scan speed.
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