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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J DESCRIPTION
The highly integrated SG5841/J series of PWM controllers provides several features to enhance the performance of flyback converters. To minimize standby power consumption, a proprietary green-mode function provides off-time modulation to continuously decrease the switching frequency at light-load conditions. This green-mode function enables the power supply to meet international power conservation requirements. To further reduce power consumption, SG5841/J is manufactured using the BiCMOS process. This allows a low start-up current, around 14A, and an operating current of only 4mA. As a result, a large start-up resistance can be used. The SG5841/J built-in synchronized slope compensation achieves stable peak-current-mode control. The proprietary internal sawtooth power-limiter ensures constant output power limit over a wide range of AC input voltages, from 90VAC to 264VAC. SG5841/J provides many protection functions. In addition to cycle-by-cycle current limiting, the internal open-loop protection circuit ensures safety should an open-loop or output-short-circuit failure occur. PWM output is disabled until VDD drops below the UVLO lower limit, then the controller starts again. An external NTC thermistor can be applied for over-temperature protection. SG5841/J is available in an 8-pin DIP or SOP package.
FEATURES
Green-Mode PWM Controller Low Start-Up Current (14A) Low Operating Current (4mA) Programmable PWM Frequency with Hopping Peak-Current-Mode Control Cycle-by-Cycle Current Limiting Synchronized Slope Compensation Leading-Edge Blanking Constant Output Power Limit Totem Pole Output with Soft Driving VDD Over-Voltage Clamping Programmable Over-Temperature Protection (OTP) Internal Open-Loop Protection VDD Under-Voltage Lockout (UVLO) GATE Output Maximum Voltage Clamp (18V)
APPLICATIONS
General-purpose switch-mode power flyback power converters, including: Power Adapters Open-Frame SMPS supplies and
TYPICAL APPLICATION
SG5841/J
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J PIN CONFIGURATION
GND FB VIN RI GATE VDD SENSE RT
MARKING DIAGRAMS
H: J = with Frequency Hopping Null = without Frequency Hopping T: D = DIP, S = SOP P: Z = Lead Free Null=regular package XXXXXXXX: Wafer Lot Y: Year; WW: Week V: Assembly Location
SG5841HTP XXXXXXXXYWWV
ORDERING INFORMATION
Part Number
SG5841JSZ SG5841JDZ SG5841SZ SG5841DZ
Frequency Hopping
Yes Yes No No
Pb-Free
Package
8-Pin SOP 8-Pin DIP 8-Pin SOP 8-Pin DIP
PIN DESCRIPTIONS
Pin No.
1
Symbol
GND
Function
Ground
Description
Ground. The signal from the external compensation circuit is fed into this pin. The PWM duty cycle is determined in response to the signal from this pin and the current-sense signal from Pin 6. If FB voltage exceeds the threshold, the internal protection circuit disables PWM output after a predetermined delay time. For start-up, this pin is pulled high to the rectified line input via a resistor. Since the start-up current requirement of the SG5841/J is very small, a large start-up resistance can be used to minimize power loss. A resistor connected from the RI pin to GND pin provides the SG5841/J with a constant current source. This determines the center PWM frequency. Increasing the resistance reduces PWM frequency. Using a 26K resistor results in a 65KHz center PWM frequency. For over-temperature protection. An external NTC thermistor is connected from this pin to the GND pin. The impedance of the NTC decreases at high temperatures. Once the voltage of the RT pin drops below a fixed limit, PWM output is disabled. Current sense. The sensed voltage is used for peak-current-mode control and cycle-by-cycle current limiting. Power supply. If VDD exceeds a threshold, the internal protection circuit disables PWM output. The totem-pole output driver for the power MOSFET, which is internally clamped below 18V.
2
FB
Feedback
3
VIN
Start-Up Input
4
RI
Reference Setting Temperature Detection Current Sense Power Supply Driver Output
5
RT
6 7 8
SENSE VDD GATE
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
BLOCK DIAGRAM
5841J only
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter
VVDD VVIN VFB VSENSE VRT VRI PD RJA RJC TJ TSTG TL VESD,HBM VESD,MM Supply Voltage Input Terminal Input Voltage to FB Pin Input Voltage to SENSE Pin Input Voltage to RT Pin Input Voltage to RI Pin Power Dissipation (TA < 50C ) Thermal Resistance (Junction-to-Air) Thermal Resistance (Junction-to-Case) Operating Junction Temperature Storage Temperature Range Lead Temperature (Wave Soldering or Infrared, 10 Seconds) Electrostatic Discharge Capability, Human Body Model Electrostatic Discharge Capability, Machine Model
Value
30 30 -0.3 to 7.0 -0.3 to 7.0 -0.3 to 7.0 -0.3 to 7.0 DIP SOP DIP SOP DIP SOP 800.0 400.0 82.5 141.0 59.7 80.8
Unit
V V V V V V mW C/W C/W C C C KV V
-40 to +125 -55 to +150 260 3.0 250
* All voltage values, except differential voltages, are given with respect to GND pin. * Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device.
RECOMMENDED OPERATING CONDITIONS
Symbol
TA
Parameter
Operating Ambient Temperature
Value
-20 to +85
Unit
C
* For proper operation.
ELECTRICAL CHARACTERISTICS
VDD = 15V, TA = 25C, unless otherwise noted.
VDD Section
Symbol
VDD-OP VDD-ON VDD-OFF IDD-ST IDD-OP VDD-CLAMP tD-VDDCLAMP
Parameter
Continuously Operating Voltage Start Threshold Voltage Minimum Operating Voltage Start-up Current Operating Supply Current VDD Over-Voltage-Clamping Level
Test Condition
Min.
15 9
Typ.
16 10 14 4
Max.
24.7 17 11 30 5
Unit
V V V A mA V
VDD=VDD-ON-0.16V VDD=15V, RI=26K, GATE=OPEN 28 50
29 100 200
VDD Over-Voltage-Clamping Debounce Time RI=26K
s
RI Section
Symbol
RINOR RIMAX RIMIN
Parameter
RI Operating Range Maximum RI Value for Protection Minimum RI Value for Protection
Test Condition
Min.
15.5
Typ.
230 10
Max.
36.0
Unit
K K K
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
Oscillator Section
Symbol
FOSC tHOP FOSC-G FDV FDT
Parameter
Normal PWM Frequency Hopping Period Green-Mode Frequency Frequency Variation vs. VDD Deviation Center Frequency Hopping Range
Test Condition
RI=26K RI=26K (5841J only) RI=26K (5841J only) RI=26K VDD=11.5V to 24.7V
Min.
62 3.7 3.9 18
Typ.
65 4.2 4.4 22
Max.
68 4.7 4.9 25 5 5
Unit
KHz ms KHz % %
Frequency Variation vs. Temperature Deviation TA=-20 to +85C
Feedback Input Section
Symbol
AV ZFB VFB-OPEN VFB-OLP tD-OLP VFB-N VFB-G
Parameter
FB Input to Current Comparator Attenuation Input Impedance FB Output High Voltage FB Open-Loop Trigger Level Delay Time of FB pin Open-Loop Protection Green-Mode Entry FB Voltage Green-Mode Ending FB Voltage
Test Condition
Min.
1/3.75 4
Typ.
1/3.20 6 4.5 29 2.1 VFB-N-0.5
Max.
1/2.75 7 4.8 32 2.3
Unit
V/V K V V ms V V
FB pin open RI=26K RI=26K RI=26K
5 4.2 26 1.9
Current-Sense Section
Symbol
ZSENSE VSTHFL VSTHVA tPD tLEB
Parameter
Input Impedance Current Limit Flatten Threshold Voltage Current Limit Valley Threshold Voltage Propagation Delay to GATE Output Leading-Edge Blanking Time
Test Condition
Min.
0.85
Typ.
12 0.90 0.22 150
Max.
0.95 200 350
Unit
K V V ns ns
VSTHFL-VSTHVA RI=26K RI=26K 200
270
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
GATE Section
Symbol Parameter
DCYMAX VGATE-L VGATE-H tr tf IO Maximum Duty Cycle Output Voltage Low Output Voltage High Rising Time Falling Time Peak Output Current VDD=15V, IO=50mA VDD=12.5V, IO=50mA VDD=15V, CL=1nF VDD=15V, CL=1nF VDD=15V, GATE=6V VDD=24.7V 7.5 150 30 230 18 19 250 50 350 90
Test Condition
Min.
60
Typ.
65
Max.
70 1.5
Unit
% V V ns ns mA V
VGATE-CLAMP Gate Output Clamping Voltage
RT Section
Symbol Parameter
IRT VRTTH VRT-RLS tD-OTP Output Current of RT Pin Trigger Voltage for Over-Temperature Protection OTP Release Voltage Over-Temperature Debounce RI=26K 60
Test Condition
RI=26K
Min.
92 0.585
Typ.
100 0.620 VRTTH +0.03 100
Max.
108 0.655 140
Unit
A V V s
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
TYPICAL CHARACTERISTICS
S tart-up C urrent (IDD-S T ) vs Temperature
30 26
5.0 4.5
O perating S upply C urrent (IDD-OP ) vs Temperature
IDD-S T (uA )
22 18 14 10 -40 -25 -10 5 20 35 50 65 80 95 110 125
IDD-O P (mA)
4.0 3.5 3.0 2.5 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ( )
Temperature ( )
O peration C urrent (IDD-O P ) vs VDD Voltage
15 12 17.0
S tart T hreshold V oltage (V DD-O N) vs T emperature
IDD-O P (mA)
16.5 9
GATE = 1000pF
V DD-O N (V )
16.0
6
GATE = OPEN
3 0 11 13 15 17 19 21 23 25 27 29
15.5
15.0 -40 -25 -10 5 20 35 50 65 80 95 110 125
VDD Voltage (V)
Temperature ( )
M in. O perating V oltage (V DD-O F F ) vs Temperature
11.0 68 67 10.5
P WM F requenc y (F os c ) vs Temperature
V DD-O F F (V)
F os c (Khz )
-40 -25 -10 5 20 35 50 65 80 95 110 125
66 65 64 63
10.0
9.5
9.0
62 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ( )
Temperature ( )
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
Max. D uty C ycle (D C Y MA X .) vs T emperature
70 68
T rigger V oltage for Over-temperature P rotection (V RT T H) vs T emperature
0.66 0.65 0.64
DC Y MA X . (%)
66 64 62 60 -40 -25 -10 5 20 35 50 65 80 95 110 125
V (RT T H) (V)
0.63 0.62 0.61 0.60 0.59 0.58 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ( )
Temperature ( )
Output C urrent of R T pin (IRT ) vs T emperature
108
104
IRT (uA)
100
96
92 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ( )
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
Current Sensing / PWM Current Limiting
Peak-current-mode control is utilized in SG5841/J to regulate output voltage and provide pulse-by-pulse current limiting. The switch current is detected by a sense resistor into the SENSE pin. The PWM duty cycle is determined by this current sense signal and the feedback voltage. When the voltage on the SENSE pin reaches around VCOMP = (VFB-1.0)/3.2, a switch cycle is terminated immediately. VCOMP is internally clamped to a variable voltage around 0.85V for output power limit.
OPERATION DESCRIPTION Start-up Current
Typical start-up current is only 14A, so that a high resistance and low-wattage start-up resistor can be used to minimize power loss. For an AC/DC adapter with universal input range, a 1.5M, 0.25W start-up resistor and a 10F/25V VDD hold-up capacitor are enough for this application.
Operating Current
Operating current is around 4mA. The low operating current enables better efficiency and reduces the requirement of VDD hold-up capacitance.
Leading-Edge Blanking
Each time the power MOSFET is switched on, a turn-on spike occurs at the sense-resistor. To avoid premature termination of the switching pulse, a leading-edge blanking time is built in. During this blanking period, the current-limit comparator is disabled and cannot switch off the gate drive.
Green-Mode Operation
The proprietary green-mode function provides off-time modulation to continuously decrease the PWM frequency under light-load conditions. To avoid acoustic noise problems, the minimum PWM frequency is set above 22kHz. This green-mode function dramatically reduces power consumption under light-load and zero-load conditions. Power supplies using a SG5841/J controller can meet even the most restrictive international regulations regarding standby power consumption.
Under-Voltage Lockout (UVLO)
The turn-on and turn-off thresholds of SG5841/J are fixed internally at 16V/10V. During start-up, the hold-up capacitor must be charged to 16V through the start-up resistor for the IC to be enabled. The hold-up capacitor continues to supply VDD before the energy can be delivered from auxiliary winding of the main transformer. VDD must not drop below 10V during this start-up process. This UVLO hysteresis window ensures that hold-up capacitor is adequate to supply VDD during start-up.
Oscillator Operation
A resistor connected from the RI pin to the GND pin generates a constant current source for the SG5841/J controller. This current is used to determine the center PWM frequency. Increasing the resistance reduces PWM frequency. Using a 26K resistor, RI, results in a corresponding 65KHz PWM frequency. The relationship between RI and the switching frequency is:
Gate Output / Soft Driving
The SG5841/J BiCMOS output stage is a fast totem pole gate driver. Cross conduction has been avoided to minimize heat dissipation, increase efficiency, and enhance reliability. The output driver is clamped by an internal 18V Zener diode to protect power MOSFET transistors against undesirable gate over-voltage. A soft driving waveform is implemented to minimize EMI.
fPWM
=
1690 RI (K )
(KHz) ----------------------------
(1)
The range of the PWM oscillation frequency is designed as 47KHz ~ 109KHz. SG5841J also integrates frequency hopping function internally. The frequency variation ranges from around 62KHz to 68KHz for a center frequency of 65KHz. The frequency hopping function helps reduce EMI emission of a power supply with minimum line filters.
Built-in Slope Compensation
The sensed voltage across the current-sense resistor is used for peak-current-mode control and pulse-by-pulse current limiting. Built-in slope compensation improves stability or prevents sub-harmonic oscillation. SG5841/J inserts a synchronized, positive-going ramp at every switching cycle.
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
When VDD goes below the turn-off threshold (e.g., 10V) the controller is totally shut down. VDD is charged up to the turn-on threshold voltage of 16V through the start-up resistor until PWM output is restarted. This protection feature remains activated as long as the over-loading condition persists. This prevents the power supply from overheating due to over loading conditions.
Constant Output Power Limit
When the SENSE voltage across the sense resistor, RS, reaches the threshold voltage, around 0.85V, the output GATE drive is turned off after delay tPD. This delay introduces additional current, proportional to tPD * VIN / LP. The delay is nearly constant regardless of the input voltage VIN. Higher input voltage results in larger additional current and the output power limit is higher than under low input line voltage. To compensate this variation for a wide AC input range, a sawtooth power-limiter (saw limiter) is designed to solve the unequal power-limit problem. The saw limiter is designed as a positive ramp signal (Vlimit_ramp) and fed to the inverting input of the OCP comparator. This results in a lower current limit at high-line inputs than at low-line inputs.
Noise Immunity
Noise on the current sense or control signal may cause significant pulse width jitter, particularly in the continuous-conduction mode. Slope compensation helps alleviate this problem. Good placement and layout practices should be followed. Avoiding long PCB traces and component leads, locating compensation and filter components near to the SG5841/J, and increasing the power MOS gate resistance improves performance.
VDD Over-Voltage Clamping
VDD over-voltage clamping has been built in to prevent damage due to abnormal conditions. Once the VDD voltage is over the VDD over-voltage clamping voltage (VDD-CLAMP) and lasts for tD-VDDCLAMP, the PWM pulses are disabled until the VDD voltage drops below the VDD over-voltage clamping voltage.
Thermal Protection
An NTC thermistor RNTC in series with a resistor RA can be connected from pin RT to ground. A constant current IRT is output from pin RT. The voltage on the RT pin can be expressed as VRT = IRT x (RNTC + RA), in which IRT = 2 x (1.3V / RI). At high ambient temperature, RNTC is smaller, such that VRT decreases. When VRT is less than 0.62V, the PWM is completely turned off.
Limited Power Control
The FB voltage increases every time the output of the power supply is shorted or over loaded. If the FB voltage remains higher than a built-in threshold longer than tD-OLP, PWM output is turned off. As PWM output is turned off, the supply voltage VDD begins decreasing.
t D - OLP (ms)
= 1 . 115 x R I (K ) -----------------
(2)
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
REFERENCE CIRCUIT
Q1 1 1 VZ1 L1 C1 R2 1 3 1 3 TR 1 L2 C2 4 C4 3 2 1 + R5 C3 1 R3 2 C6 R4 C7 + 2 +C8 R6 T1 3 2 1 L3 2 4 2 4 2 Vo+ D1 D3 2 CN1 1 2 3 F1 R1 BD1 C5
1
1
1
D2 2
2
D4
2
1 2 3 4 R9
GND FB VIN RI SG5841/J
GATE VDD SENSE RT
8 7 6 5 R10 C11 THER2 R16
1 3
1
U1
Q2
R12
R11 C9 2 + R8 1
4
U2
C12 R13 3 K2 C10 R14 R15 A
1
U3
R
VO+
BOM
Reference
BD1 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 D1 D2 D3 D4 F1 L1 L2 L3 Q1
Component
BD 4A/600V XC 0.68F/300V XC 0.1F/300V CC 0.01F/500V EC 120/400V YC 222p/250V CC 1000pF/100V EC 1000F/25V EC 470F/25V EC 10F/50V CC 222pF/50V CC 470pF/50V CC 102pF/50V(Option) LED Diode BYV95C TVS P6KE16A Diode FR103 FUSE 4A/250V Choke (900H) Choke (10mH) Inductor (2H) Diode 20A/100V
Reference
Q2 R1,R2 R3 R4 R5,R7 R6 R8 R9 R10 R11 R12 R13 R14 R15 R16 THER2 T1 U1 U2 U3 VZ1
Component
MOS 7A/600V R 1Mohm 1/4W R 100Kohm 1/2W R 47ohm 1/4W R 750Kohm 1/4W R 2Kohm 1/8W R 0.3ohm 2W R 33Kohm 1/8W R 4.7Kohm 1/8W 1% R 470ohm 1/8W R 0 ohm 1/8W R 4.7Kohm 1/8W R 154Kohm 1/8W R 39Kohm 1/8W R 100ohm 1/8W Thermistor TTC104 Transformer (600H-PQ2620) IC SG5841/J IC PC817 IC TL431 VZ 9G
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2
R7
Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
PACKAGE INFORMATION 8PINS-DIP (D)
D
8 5
X
E1
E
eB
1
4
A1
A2
L b1 b e
Dimensions
Millimeters Min. Typ.
0.381 3.175 3.302 1.524 0.457 9.017 6.223 2.921 8.509 0 9.271 7.620 6.350 2.540 3.302 9.017 7 3.810 9.525 15 0.115 0.335 0 6.477 0.245 10.160 0.355 3.429
A
Inches Min.
0.015 0.125 0.130 0.060 0.018 0.365 0.300 0.250 0.100 0.130 0.355 7 0.150 0.375 15 0.255 0.400 0.135
Symbol
A A1 A2 b b1 D E E1 e L eB
Max.
5.334
Typ.
Max.
0.210
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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Product Specification Highly Integrated Green-Mode PWM Controller
SG5841/J
8PINS-SOP(S)
C
8
5
1 b
4 e
D
A1
A
Dimensions
Symbol
A A1 b c D E e F H L
Millimeter Min. Typ.
1.346 0.101 0.406 0.203 4.648 3.810 1.016 5.791 0.406 0
Max.
1.752 0.254
1.270 0.381X45
4.978 3.987 1.524 6.197 1.270 8
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
H F
E
L
Inch Min.
0.053 0.004
Typ.
0.016 0.008
Max.
0.069 0.010
0.183 0.150 0.040 0.228 0.016 0
0.050 0.015X45
0.196 0.157 0.060 0.244 0.050 8
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Product Specification Highly-Integrated Green-Mode PWM Controller
SG5841/J
(c) System General Corp. Version 1.3.1 (IAO33.0017.B6)
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