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SD4840/4841/4842/4843/4844
CURRENT MODE PWM CONTROLLER WITH BUILT-IN HIGH VOLTAGE MOSFET
DESCRIPTION
SD4840/4841/4842/4843/4844 is a current mode PWM controller with low standby power and low start current for power switch. In standby mode, the circuit enters burst mode to reduce the standby power dissipation. The switch frequency is 67KHz with 2.5 KHz jitter frequency for low EMI. The stress on transformer during power on is reduced by the builtin 15ms soft start circuit to avoid the saturation of transformer. SD4840/4841/4842/4843/4844 includes under voltage lock-out, over voltage protection, leading edge blanking, over current protection and the temperature protection. The circuit will restart automatically until the system is normal after the protection is active.
FEATURES
* Lower start-up current (Typ.6A) * Frequency jitter for low EMI * Overcurrent protection * Overvoltage protection * Undervoltage lockout * Built-in temperature protection * Built-in high voltage MOSFET
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APPLICATIONS
* Switch power
* Built-in soft start * Burst mode operation * Cycle by cycle current limit
ORDERING INFORMATION
Part No. SD4840P67K65 SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 DIP-8-300-2.54 Package Marking SD4840P67K65 SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65
Note: P denotes it is available in DIP8 package, 67k denotes 67KHz, and 65 denotes withstand voltage is 650V.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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SD4840/4841/4842/4843/4844
TYPICAL OUPUT POWER CAPABILITY
Device SD4840P67K65 SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 190~265VAC Adapter 7W 10W 12W 14W 16W Open 9W 14W 17W 19W 21W Adapter 5W 8W 10W 12W 14W 85~265VAC Open 7.2W 12W 14W 15W 18W
BLOCK DIAGRAM
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ABSOLUTE MAXIMUM RATING
Characteristics Drain-Gate Voltage (RGS=1M) Gate-Source (GND) Voltage SD4840P67K65 SD4841P67K65 Drain Current Pulse (note1) SD4842P67K65 SD4843P67K65 SD4844P67K65 IDM Symbol VDGR VGS Rating 650 30 4 6 8 11 14 A Unit V V
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Characteristics SD4840P67K65 Continuous Drain Current (Tamb=25C) SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 Signal Pulse Avalanche Energy(note 2) SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 Power Supply Voltage Analog Input Voltage Total Power Dissipation Operating Junction Temperature Operating Temperature Storage Temperature 2. L=51mH, starting Tj=25C EAS ID Symbol Rating 1 1.5 2 3 4 15 30 68 140 200 mJ A Unit
VCC,MAX
VFB PD Darting TJ Tamb TSTG
21 -0.3~ VSD 1.5 0.017 +160 -25~ +85 -55~+150
V V W W/C C C C
Note: 1. Pulse width is limited by maximum junction temperature.
ELECTRICAL CHARACTERISTICS (sense MOSFET part, unless otherwise specified, Tamb=25c)
Characteristics Drain-Source Breakdown Voltage Zero Gate Voltage Drain Current
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Symbol
Test conditions VDS=Max. VGS=0V
Min. 650 -----
Typ. ---14.0 8.0 5.0 4.0 3.0 210 250 550 640 840 18 25 38 40 44
Max. -50 200 16.8 9.6 6.0 4.8 3.6 -----------
Unit V A A
BVDSS VGS=0V, ID=50A IDSS VDS=0.8Max. VGS=0V Tamb=125C
SD4840P67K65 Static DrainSource On Resistance SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 Input Capacitance SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 Output Capacitance SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 Coss VGS=0V, VDS=25V, f=1MHz Ciss VGS=0V, VDS=25V, f=1MHz RDS(ON) VGS=10V, ID=0.5A
--------------
pF
pF
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Characteristics SD4840P67K65 Reverse Transfer Capacitance SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 Turn On Delay Time SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 SD4841P67K65 Rise Time SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 Turn Off Delay Time SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 SD4840P67K65 SD4841P67K65 Fall Time SD4842P67K65 SD4843P67K65 SD4844P67K65
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Symbol
Test conditions
Min. ---
Typ. 8 10 17 30 40 10 12 20 33 40 3 4 15 19 25 27 30 55 70 90 8 10 25 32 42
Max. --------------------------
Unit
Crss
VGS=0V, VDS=25V, f=1MHz
------
pF
td(ON) VDD=0.5BVDSS, ID=25mA
------
nS
tr
VDD=0.5BVDSS, ID=25mA
------
nS
td(OFF) VDD=0.5BVDSS, ID=25mA
------
nS
tf
VDD=0.5BVDSS, ID=25mA
----
nS
ELECTRICAL CHARACTERISTICS (unless otherwise specified, Tamb=25c)
Characteristics Undervoltage Section Start Threshold Voltage Stop Threshold Voltage Oscillator Section Oscillate Frequency Frequency Jitter Frequency Change With Temperature Maximum Duty Cycle Feedback Section Feedback Source Current Shutdown Feedback Voltage Shutdown Delay Current IFB VSD Idelay 5VVFBVSD 0VVFB3V 0.7 5.5 3.5 0.9 6.0 5.0 1.1 6.5 6.5 mA V A FOSC FMOD -Dmax 25CTamb+85C 61 1.5 -72 67 2.0 5 77 73 2.5 10 82 KHz KHz % % Vstart Vstop 11 7 12 8 13 9 V V Symbol Test conditions Min. Typ. Max. Unit
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Characteristics Built-in Soft Start Time Current Limit SD4840P67K65 Peak Current Limit SD4841P67K65 SD4842P67K65 SD4843P67K65 SD4844P67K65 Burst mode Burst Mode High Voltage Burst Mode Low Voltage Protection Section Overvoltage Protection Thermal Shutdown Leading-edge Blanking Time Total Standby Current Start Current Supply Current (Control Part) Istart Iop VCC=11V VCC=12V -1 6 3 20 5 A mA Vovp Tsd TLEB 18 125 200 19 140 ----V C ns VBURH VBURL 0.4 0.25 0.5 0.35 0.6 0.45 V V Iover Max. inductor current 0.53 0.67 0.80 1.10 1.35 0.60 0.75 0.90 1.20 1.50 0.67 0.83 1.00 1.30 1.65 A Symbol ts Test conditions VFB=4V Min. 10 Typ. 15 Max. 20 Unit ms
PIN CONFIGURATION
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PIN DESCRIPTION
Pin No. 1 2 Pin Name SGND PGND VCC FB NC Drain I/O I/O O MOSFET Ground. Power supply pin. Feedback input pin. Not connected. Drain pins. Function description Ground for control part.
3 4
5 6,7,8
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SD4840/4841/4842/4843/4844
FUNCTION DESCRIPTION
SD4840/4841/4842/4843/4844 is designed for off-line SMPS, consisting of high voltage MOSFET, optimized gate driver and current mode PWM controller which includes frequency oscillator and various protections such as undervoltage lockout, overvoltage protection, overcurrent protection and overtemperature protection. Frequency jitter generated from oscillator is used to lower EMI and built-in soft start is used for reducing transformer stress when the circuit is powered on. Burst mode is adopted during light load to lower standby power dissipation, and function of lead edge blanking eliminates the MOSFET error shutdown caused by interference through minimizing MOSFET turning on time. Few peripheral components are needed for higher efficiency and higher reliability and it is suitable for flyback converter and forward converter. 1. Under Voltage Lockout and Self-Start
At the beginning, the capacitor connected to pin VCC is charged via start resistor by high voltage AC and the circuit start to work if voltage at Vcc is 12V. The output is shutdown if there is any protection during normal operation and Vcc is decreased because of powering of auxiliary winding. The whole control circuit is shutdown if voltage at Vcc is 8V below to lower current dissipation and the capacitor is recharged for restarting.
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2.
Built-In Soft Start Circuit
In order to decrease transformer stress and to prevent its saturation during power on, it is recommended to increase peak current value of primary winding slowly by increasing feedback voltage slowly. After about 15ms, the soft start is completed and it has no effect on normal operation.
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SD4840/4841/4842/4843/4844
3. Frequency Jitter
The oscillation frequency is kept changed for low EMI and decreasing radiation on one frequency. The oscillation frequency changes within a very small range to simplify EMI design. The rule of frequency changing: change from 65KHz to 69KHz. 4. Light Load Mode Working in this mode to reduce power dissipation. It works normally when FB is 500mV above and during 350mVwww..com
5.
Leading Edge Blanking
For this current-controlled circuit, there is pulse peak current during the transient of switch turning on and there is an error operation if the current is sampled during this time. And leading edge blanking is adopted to eliminate this error operation. The output of PWM comparator is used for controlling shutdown after the leading edge blanking if there is any output drive.
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SD4840/4841/4842/4843/4844
6. Over Voltage Protection
The output is shutdown if voltage at Vcc exceeds the threshold and this state is kept until the circuit is powered on reset. 7. Overload Protection
FB voltage increase if there is overload and the output is shutdown when FB voltage is up to the feedback shutdown voltage. This state is kept until the circuit is powered on reset. 8. Peak Current Limit Cycle By Cycle
During each cycle, the peak current value is decided by the comparison value of the comparator, which will not exceed the peak current limited value to guarantee the current on MOSFET will not be more than the rating current. The output power will not increase if the current reaches the peak value to limit the max. output power. The output voltage decreases and FB voltage increases if there is overload and corresponding protection occurs. 9. Abnormal Over Current Protection
That secondary diode is short, or the transformer is short will cause this event. At this time, once it is over current in spite of the leading edge blanking (L.E.B) time, protection will begin after 350nS, and is active for every cycle. When the voltage on the current sense resistor is 1.6V, this protection will occur and the output is shut down. This state is kept until the under voltage occurs, and the circuit will start. 10. Thermal Shutdown If the circuit is over temperature, the over temperature protection will shut down the output to prevent the circuit from damage. This state is kept until the under voltage occurs, and the circuit will start.
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HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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SD4840/4841/4842/4843/4844
TYPICAL APPLICATION CIRCUIT
Note: 1. 2.
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The circuit and parameters are for reference only, please set the parameters of the real application circuit based on the real test. Better not to place VCC winding as inner coil.
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SD4840/4841/4842/4843/4844
PACKAGE OUTLINE
DIP-8-300-2.54 UNIT: mm
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MOS DEVICES OPERATE NOTES:
Electrostatic charges may exist in many things. Please take following preventive measures to prevent effectively the MOS electric circuit as a result of the damage which is caused by discharge: The operator must put on wrist strap which should be earthed to against electrostatic. Equipment cases should be earthed. All tools used during assembly, including soldering tools and solder baths, must be earthed. MOS devices should be packed in antistatic/conductive containers for transportation.
NoteSilan reserves the right to make changes without notice in this specification for the improvement of the design and performance. Silan will supply the best possible product for customers.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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SD4840/4841/4842/4843/4844
Attachment Revision History
Data 2008.07.07 2008.11.06 2008.12.17 REV 1.0 1.1 1.2 Original Modify the "BLOCK DIAGRAM" and "FUNCTION DESCRIPTION" Add the note for "TYPICAL APPLICATION CIRCUIT" Description Page
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