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PWM Controllers. SG3842G Datasheet

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PWM Controllers. SG3842G Datasheet






SG3842G Controllers. Datasheet pdf. Equivalent




SG3842G Controllers. Datasheet pdf. Equivalent





Part

SG3842G

Description

BiCMOS Green-Mode PWM Controllers



Feature


Product Specification BiCMOS Green-Mode PWM Controllers SG3842G/ 3843G/ 3844G/ 3845G start-up current has been reduce d to 5uA, and the minimum operating cur rent has been reduced to 5mA. Each SG38 4xG has a slew rate controlled high cur rent totem pole output, ideally suited for driving a power MOSFET while keepin g EMI low. The current-sense propagatio n delay is typical.
Manufacture

System General

Datasheet
Download SG3842G Datasheet


System General SG3842G

SG3842G; ly 50ns, resulting in significantly more effective constant power protection. D uring normal operation, a SG384xG contr oller acts as a fixed frequency PWM con troller. The PWM frequency can be easil y programmed by changing external RT an d CT values. The SG384xG includes two G reen-mode functions that dramatically r educe power usage, helping the power su pply comply with t.


System General SG3842G

he latest international power saving gui delines. To cut power consumption under light load conditions, the controller s Green-mode function will linearly d ecrease the PWM frequency in response t o decreases in the output load. Under u ltra light-load/zero-load conditions, t he RT/CT PWM oscillator periodically sh uts down, and enters into Burst-mode. T his causes the IC’s .


System General SG3842G

supply voltage to begin gradually droppi ng. Just before the supply voltage drop s below the UVLO voltage threshold, the RT/CT PWM oscillator turns back on, to prevent the supply voltage from going below the UVLO voltage. SG384xG control lers also come with Over Voltage Protec tion (OVP). This shuts down PWM output if the supply voltage ever exceeds 27V. The SG384xG serie.

Part

SG3842G

Description

BiCMOS Green-Mode PWM Controllers



Feature


Product Specification BiCMOS Green-Mode PWM Controllers SG3842G/ 3843G/ 3844G/ 3845G start-up current has been reduce d to 5uA, and the minimum operating cur rent has been reduced to 5mA. Each SG38 4xG has a slew rate controlled high cur rent totem pole output, ideally suited for driving a power MOSFET while keepin g EMI low. The current-sense propagatio n delay is typical.
Manufacture

System General

Datasheet
Download SG3842G Datasheet




 SG3842G
BiCMOS Green-Mode PWM Controllers
Product Specification
SG3842G/ 3843G/ 3844G/ 3845G
FEATURES
384x series pin-to-pin compatible
Linearly decreasing PWM frequency
Burst-mode at low/zero load
5uA start-up current
5mA operating current
Vcc over voltage protection
Cycle-by-cycle current limiting
Zero cross-conduction
Slew rate controlled high current totem pole output
Fast current sense propagation delay
Under voltage lockout (UVLO) with hysteresis
APPLICATIONS
Switching mode power supplies
Power converters
DESCRIPTION
The SG348xG series of current-mode PWM
controllers combines high performance with Green-mode
power saving features. SG348xG controllers are fully
pin-to-pin compatible with bipolar UC384x devices, but
they have improved features and functionality. SG384xG
series controllers are compatible with the BiCMOS
fabrication process, enabling the use of low start-up
current and operating currents. This feature further
improves power conversion efficiency. The minimal
start-up current has been reduced to 5uA, and the
minimum operating current has been reduced to 5mA.
Each SG384xG has a slew rate controlled high current
totem pole output, ideally suited for driving a power
MOSFET while keeping EMI low.
The current-sense propagation delay is typically
50ns, resulting in significantly more effective constant
power protection. During normal operation, a SG384xG
controller acts as a fixed frequency PWM controller. The
PWM frequency can be easily programmed by changing
external RT and CT values. The SG384xG includes two
Green-mode functions that dramatically reduce power
usage, helping the power supply comply with the latest
international power saving guidelines. To cut power
consumption under light load conditions, the controller’s
Green-mode function will linearly decrease the PWM
frequency in response to decreases in the output load.
Under ultra light-load/zero-load conditions, the RT/CT
PWM oscillator periodically shuts down, and enters into
Burst-mode. This causes the IC’s supply voltage to begin
gradually dropping. Just before the supply voltage drops
below the UVLO voltage threshold, the RT/CT PWM
oscillator turns back on, to prevent the supply voltage
from going below the UVLO voltage.
SG384xG controllers also come with Over Voltage
Protection (OVP). This shuts down PWM output if the
supply voltage ever exceeds 27V. The SG384xG series
comes in 8-pin DIP and SOP packages.
TYPICAL APPLICATION
Green-mode Operation
Oscillator Frequency vs. COMP
From bridge rectifier
120~ 380VDC
RIN
1.5M
VCC
COMP
Rac OUTPUT
10k
VREF
C21
RT 0.1u SG384x
10k
SENSE
CT
3.3n
VFB
GND
From auxiliary winding
CIN
10u
R41
100
R42
1k
C25 RS
100p 0.3
© System General Corp.
Version D.2 ( IRO33.0007.B1)
-1-
Oscillator Frequency (Fosc) vs COMP Voltage
60
50
40
30
20
10
0
1 1.5 2 2.5
COMP VOLTAGE (V)
3
www.sg.com.tw
Apr.22,2003




 SG3842G
BiCMOS Green-Mode PWM Controllers
MARKING INFORMATION
8
SG384ZGT
AXXXXXXXYYWWV
1
Z: 2, 3, 4, or 5
T: D = DIP, S = SOP
XXXXXXX: Wafer Lot
YY: Year; WW: Week
V: Assembly Location
Product Specification
SG3842G/ 3843G/ 3844G/ 3845G
PIN CONFIGURATION
COMP
VFB
SENSE
RT/CT
1
2
3
4
8 VREF
7 VCC
6 OUTPUT
5 GND
ORDERING INFORMATION
Part Number
SG3842GAD
SG3842GAS
SG3843GAD
SG3843GAS
SG3844GAD
SG3844GAS
SG3845GAD
SG3845GAS
UVLO
Start threshold
Stop threshold
16V±1V
10V±1V
8.9V±0.5V
8.1V±0.5V
16V±1V
10V±1V
8.9V±0.5V
8.1V±0.5V
Maximum duty cycle
Package
98%
98%
49%
49%
8-Pin DIP
8-Pin SOP
8-Pin DIP
8-Pin SOP
8-Pin DIP
8-Pin SOP
8-Pin DIP
8-Pin SOP
PIN DESCRIPTIONS
Pin No. Symbol Function
Description
1
COMP Compensation
Output of the Error Amplifier and input to the PWM comparator. It is used for feedback
loop compensation.
2
VFB Feedback
Inverting input of the Error Amplifier. It is normally connected to the switching power
supply output through a resistor divider.
3
SENSE Current sense
Current sense comparator input. It is internally set to 1V maximum. A voltage proportional
to the inductor current is connected to this input.
Oscillator RC timing connection. Connecting a resistor RT from this pin to Vref, and a
4 RT/CT Oscillator control capacitor CT from this pin to ground, programs the oscillator frequency and the maximum
output duty cycle.
5
GND
Ground
This pin is the combined control circuit ground and power ground.
6 OUTPUT Output
High-power, totem-pole driver output. This output drives the gate of a power MOSFET.
7
VCC
Power supply
Supply voltage input.
8
VREF
Reference voltage 5V-reference voltage output.
© System General Corp.
Version D.2 ( IRO33.0007.B1)
-2-
www.sg.com.tw
Apr.22,2003




 SG3842G
BiCMOS Green-Mode PWM Controllers
BLOCK DIAGRAM
Product Specification
SG3842G/ 3843G/ 3844G/ 3845G
VCC 7
RTCT 4
VFB 2
COMP 1
SENSE 3
+
_
+
_
VH / VL
VCC
ENB
5V
VREF
R
R
Internal
BIAS
(n-1)R Vs
R 1V
Green Mode
Controller
_
+ Comp
OSC
T-type
Q
CLK
SQ
R
5
GND
8 VREF
ENB
Output
6 OUTPUT
SG3844
SG3845
Only
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Vcc Supply voltage
Iz
VIN
ISINK
Zener current
FB/SENSE terminal input voltage
Error amplifier sink current
Pd Power dissipation
RΘ j-a
TJ
Ta
Tstg
TL
Thermal resistance
Operating junction temperature
Operating ambient temperature
Storage temperature range
Lead temperature (Soldering)
ESD Capability, HBM model
ESD Capability, Machine model
Test Condition
Low impedance source
Zener clamp
FB, SENSE
at Ta<50°C
Junction-air
-
-
-
10 sec
20 sec
DIP
SOP
DIP
SOP
DIP
SOP
Value
25
28
10
-0.3 to 5.5V
10
800
400
82.5
141
+150
-40 to 125
-65 to +150
260
220
3.0
200
Unit
V
mA
V
mA
mW
°C/W
°C
°C
°C
°C
kV
V
© System General Corp.
Version D.2 ( IRO33.0007.B1)
-3-
www.sg.com.tw
Apr.22,2003



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