Operation Of Power Supply - Toshiba TDP-TW95E Service Manual

Operation of Power Supply (APS-M602)
The APS-M602 power supply circuit shown as (Fig.1)
Input
Line Filter
AC Inout
1)Input Line Filter
A switching power supply generates a lot of electromagnetic noise. The function of the AC line Filter,
witch is made up of capacitors (e.g.C103) and inductor choke (e.g.101,L102),is to attenuate these
noise so that other equipments many not be affected.
The surge absorber Z101 which absorbs high voltage surge from the input lines. These are mounted on
the input filter.
*The fuse (F101) becomes open in order to protect other parts, when excessive current flows at
abnormal conditions.
*CN101 is connected thermo sensing element (e.g. Thermal protector.)
Power Supply is operated by CN104 shorted condition.
2) Power Factor Control Circuit
This circuit has 5 functions as below.
A) To generate stable voltage
B) To reduce input harmonic currents
C) Over current protection
D) Over voltage protection
E) (Inrush current suppression circuit)
A) Generate stable voltage
This circuit operate as step up to 370Vdc(type.)and voltage control.Actually,Q1,Q2(MC102)
are switched by MC101.
Initial voltage setting of 370V output(between pin 1 and pin 3 of CN102)has set at 370V(type.) by
VR101.(Input voltage :100Vac,max.load)
CD/DC
(InrushCurrent
Swintching
Suppression circuit)
Converter
Power factor
Control
Circuit
Lamp Output
Fig.1
Secondary
Rectifier
Circuit
Feedback
Control
6-18
Chapter 6
Output
15V
12V
6.5V
3.4V
Time Sharing
Multi-output
Control Circuit
0V
0V