Saturday, January 16, 2016

Sanyo CE22LD90-B - 20432975 - 17IPS15-4 Power supply schematics – STR-W6253D – TL494 – LCD Television repair and service - Manual Service

Category: LCD Television Repair and Service 

Contents of this article 

  • Power supply Schematic diagram 
  • STR-W6253D Details 
  • TL494 Details 




SANYO 20432975 -17IPS15-4

STR-W6253D
Description
The STR-W6200D series are current-mode PWM ICs that incorporate controller chips. These devices are manufactured using a proprietary high-voltage BCD process, and avalancheguaranteed MOSFETs. These elements allow power supply systems designs that are highly reliable and simple, with fewer peripheral components. These ICs also provide Auto-Burst mode operation, which lowers input power requirements at light loads, and improves efficiency over the entire load range and universal-input range.
Applicatons 
# TV set top box
# LCD PC monitor, LCD TV
# Printer, scanner
# General consumer, PC, and industrial applications requiring SMPS power supply with standby mode
PIN CONFIGURATION 
Number
Name
Functions
1
D/ST
MOSFET drain and input of start-up signal
2
NC
No connection
3


S/OCP


MOSFET source and input of overcurrent
detection signal

4
VCC
Input of power supply for control circuit
5
GND
Ground
6

FB

Input of constant voltage control signal


7

FM/ELP
Control input for frequency jittering control and
External Latch Protection

TL494 Pulse-Width-Modulation Control
Description
The TL494 device incorporates all the functions required in the construction of a pulse-width- modulation (PWM) control circuit on a single chip. Designed primarily for power-supply control, this device offers the flexibility to tailor the power-supply control circuitry to a specific application. The TL494 device contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, a 5-V, 5%-precision regulator, and output-control circuits.
The error amplifiers exhibit a common-mode voltage range from –0.3 V to VCC – 2 V. The dead-time control comparator has a fixed offset that provides approximately 5% dead time. The on-chip oscillator can be bypassed by terminating RT to the reference output and providing a sawtooth input to CT, or it can drive the common circuits in synchronous multiple-rail power supplies.
The uncommitted output transistors provide either common-emitter or emitter-follower output capability. The TL494 device provides for push-pull or single- ended output operation, which can be selected through the output-control function. The architecture of this device prohibits the possibility of either output being pulsed twice during push-pull operation. The TL494C device is characterized for operation from 0°C to 70°C. The TL494I device is characterized for operation from –40°C to 85°C.
PIN CONFIGURATION 
PIN NAME
NO.
DESCRIPTION
1IN+
1
Noninverting input to error amplifier 1
1IN-
2
Inverting input to error amplifier 1
2IN+
16
Noninverting input to error amplifier 2
2IN-
15
Inverting input to error amplifier 2
C1
8
Collector terminal of BJT output 1
C2
11
Collector terminal of BJT output 2
CT
5
Capacitor terminal used to set oscillator frequency
DTC
4
Dead-time control comparator input
E1
9
Emitter terminal of BJT output 1
E2
10
Emitter terminal of BJT output 2
FEEDBACK
3
Input pin for feedback
GND
7
Ground
OUTPUT CTRL
13
Selects single-ended/parallel output or push-pull operation
REF
14
5-V reference regulator output
RT
6
Resistor terminal used to set oscillator frequency
VCC
12
Positive Supply

POWER SUPPLY CIRCUIT 

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