Panasonic DP-MB310EU, Service Manual

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KX-MB2230EU/ KX-MB2270EU/ KX-MB2515EU/ KX-MB2545EU/ KX-MB2575EU/ DP-MB310EU
6.7.2.1. Motor driver
IC502 is the motor driver AN44071A.
This motor driver can drive both FB and ADF motors with 1 chip, and can supply up to 1.7A/phase and support up to 2W1-2
phase excitation.
When "CRMEN" signal (IC502_pin40) becomes "H", FB block of motor driver is activated, and motor currents are supplied
from IC502_pin24, pin28, pin29 and pin33 to drive the FB motor coils.
When "ADFMEN" signal (IC502_pin45) becomes "H", ADF block of motor driver is activated, and motor currents are supplied
from IC502_pin1, pin5, pin52 and pin56 to drive the ADF motor coils.
FB motor excitation mode is selected by the logic level of "ST1AB", "ST2AB" and "ST3AB" (IC502_pin35-pin37).
ADF motor excitation mode is selected by the logic level of "ST1CD" , "ST2CD" and "ST3CD"(IC502_pin50-pin48).
The relation between motor excitation mode and logic level of "ENABLEAB"/"ENABLECD", "ST1AB"/"ST1CD", "ST2AB"/
"ST2CD" and "ST3AB"/"ST3CD" are shown in below table.
Table1: Motor driver Excitation mode *(pinxx) represents the pin No. of IC502
"DIRAB"(IC502_pin38) and "DIRCD"(IC502_pin47) determine the direction of motor rotation.
Although "DIRCD" determines the Main motor rotation direction, direction is not changed.
So "DIRCD" is fixed "H" level.
The relation between these signals and motor rotation directions are shown in below table.
Table2: Motor rotation direction *(pinxx) represents the pin No. of IC502
After setting the above signals, clock signal is supplied from IC300_pinA10 to "CLKAB"(IC502_pin39) and
"CLKCD"(IC502_pin46).
Whenever clock signal is supplied, current value and direction supplied to Scan motors change according to the exci-
tation mode which is determined by above signal levels.
The clock frequency also determines the motor speed.
6.7.2.2. 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, VREFAB and VREFCD voltages of IC502 is controlled.
When VREFAB and VREFCD voltages are high, motor currents are increased, and the voltages are low, motor currents are
reduced.
2. Circuit Diagram
Please refer to the circuit diagram shown in the block diagram of Scanner motor drive circuit (P.52) .
3. Circuit explanation
For the sake of VREFAB and VREFCD voltage control, PWM pulse is supplied from IC300_pinD8.
PWM pulse is integrated by R671, R672 and C657, then converted to DC voltage.
ENABLEAB(pin40)
or
ENABLECD(pin45)
ST1AB(pin35)
or
ST1CD(pin50)
ST2AB(pin36)
or
ST2CD(pin49)
ST3AB(pin37)
or
ST3CD(pin48)
Excitation
mode
L - - - Disable
H L L L 2 Phase(Not
used)
H L H L N1-2phase
H H L L F1-2phase
H H H L W1-2phase
H L L H 2W1-2phase
Motor DIRAB(pin38) Operation Mode
FB
L Scan
H Return
Motor DIRCD(pin47) Operation Mode
ADF
L FEED
H Not used