Marantz CDR631 Service Manual

23
7.4 Power Supply Unit P816
7.4.1 Description of P816
MOSFET Q825 is used as a power switch controlled by the
controller Q810. When the switch is closed, energy is
transferred from mains to the transformer. This energy is
supplied to the load when the switch is opened. Through
control of the switch-on time, the energy transferred in each
cycle is regulated so that the output voltages are independent
of load or input voltage variations. The controlling device
MC44603 is an integrated pulse width modulator. A clock
signal initiates power pulses at a fixed frequency. The
termination of each output pulse occurs when a feedback
signal of the inductor current reaches a threshold set by the
error signal. In this way the error signal actually controls the
peak inductor current on cycle-by-cycle basis.
Figure 7-18 ‘Blockdiagram P816’
Description of controller MC44603
The MC44603 is an enhanced high performance controller that
is specifically designed for off-line and DC-to-DC converter
applications. This device has the unique ability of automatically
changing operating modes if the converter output is
overloaded, unloaded or shorted. The MC44603 has several
distinguishing features when compared to conventional SMPS
controllers. These features consist of a foldback facility for
overload protection, a standby mode when the converter output
is slightly loaded, a demagnetization detection for reduced
switching stresses on transistor and diodes, and a high current
totem pole output ideally suited for driving a power MOSFET. It
can also be used for driving a bipolar transistor in low power
converters. It is optimised to operate in discontinuous mode but
can also operate in continuous mode. Its advanced design
allows use in current mode or voltage mode control
applications.
Pin connections
Figure 7-19
Rref
R Frequency Standby
Voltage feedback Input
Error Amp Output
R Power Standby
Soft-Start/Dmax/
Voltage Mode
Sync Input
Overvoltage Protection (OVP)
Current Sense Input
Demag. Detection
Foldback Input
107
CT
8 9
6
5
11
12
Output
Gnd
VC
VCC
3
4
2
14
13
15
1 16
CL 96532076_030.eps
290799
ERROR
AMP
IREFSYNC
RF
STANDBY
RP
STANDBY
VOLTAGE
VREF
VSB
OUT
2.5V
FEEDBACK
E/A OUT
FOLDBACK
INPUT
FOLDBACK
=1
DMAX&
SOFT-START
CONTROL
SOFTSTART
&DMAXSENSEINPUT
CURRENT
OVER
VOLTAGE
MANAGEMENT
OVER
VOLTAGE
PROTECT
BUFFER
VREF VOCTHERMAL
SHUTDOWN
LATCH
Q
UVL01
IREF
SUUPLY
INITIZLIZATION BLOCK
REFERENCE
BLOCK
VREF IREF
(REDUCED FREQUENCY)
STANDBY
OSCILLATOR
DEMAGNETISATION
MANAGEMENT
DEMAGINETIZATION
DETECT
MC44603P
UVL01
L831
Q810
GND
+5V
+5V
GND
GND
GND
+12V
-8V
GND
GND
GND
+12V
+5V
1
2
3
4
6
11
75
13
14
12
15
10
9
8
16
U810
U811
SELECT
JUMPER
(-8V)
+12V
+12V
-12V
(-8V)
-12V
-12V/-8V
1
4
5
6
7
8
9
10
11
12
13
14
+4.1V
-34V
SWITCHING POWER SUPPLY PCB. (P816)
S1WB
4.7/50V
10k
22
100/25V
2SK2943
1k
1.5
10
µ H
0.1
100
15
2200pF
180
0.1
2.2/50V
330
1500p
180k1k
15k 15k 4700pF
470p
22k
6.8
µ H
1
µ H
10k
2SC
2SA
1k
10k
10k
10k
10
µ H
PC123F
LM317
1.5
0.1
250V
0.22
250V
18k
1/2W
1.8k
1.8k
330
/16V
100/6.3V
2200
/10V
10/50V
220/50V
1000
/16V
2.2
µ H
1k
220
/16V 3.3k 100
1.8k
0.022
TL431100
7908
22k
22k
100/25
10k
PC123F
100/25
1k
AG01
RK46
AG01
RU4YX
AG01
10uH
0.1
2SC2878
820pF
82pF
NP0
82k
18k
AG01
AG01
24V
10uH
220
/16V
10k
0.1
10
220
560
0.1
4.7
µ H
4.7
µ H
220
/16V
100
/16V
100
/25V
120
/400V
18k
1/2W
0.01
0.1
470pF
/1kV
1
4.7k
330k
(UL/CSA,MITI)
1M(CB)
0.1
0.1
0.1
681
1%
2.21k
1%
10
µ H
470pF
/400V
470pF
/400V
470pF
/400V
220/16V
100/10V
OPTION
OPTION
J820
J821
J801
L820
D802
C829
R829
R811
C833
D806
D807
Q825
L825
R825
R827
L832
C811
R812
R813
C813
R816
C814
C810
R809
C809
R807R806
R805 R804 C804
C803
R802
L856
L861
R861
Q861
Q862
R862
R863
R864
R865
L862
D868
Q801
L831
Q851
R828
J851
S815
F820
C819
C820
R823
R815
R814
C856
J852
C852
C854
C857
C862
C864
C867
C868
L867
R866
C872
R881 R882
R883
C882
D881R887
Q871
D862
J828
R891
R892
C891
R893
Q892
C892
R894
D803
D804
D851
D856
D861
D866
D871
L866
L871
L873
C877
Q891
C802
C801
R801
R808
D814
D832
D829
L872
C873
R810
C855
R853
R852
R851
C860
L851
L853
C869
C875
C881
C821
R832
G815
J891
C898
C827
R826
R803
R819
C851
C861
C871
C866
R885
R884
R886
L854
L852
C825
C826
C828
C876
C859
R835
D835

Marantz CDR631 Specifications

General

Brand	Marantz
Model	CDR631
Category	Recording Equipment
Language	English