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.
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
# 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.
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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