Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller FEATURES Green-mode PWM Controller Low Start-Up Current (8uA) Low Operating Current (4mA) Programmable PWM frequency with Jittering Peak-current-mode Operation Cycle-by-Cycle Current Limiting Synchronized Slope Compensation Leading-Edge Blanking Constant Output Power Limit (Full AC Input Range) VDD Over Voltage Protection (OVP) Programmable Over Temperature Protection (OTP) Internal Latch Circuit (OTP, OVP) Options Internal Open-loop Protection APPLICATIONS General-purpose switch mode power supplies and flyback power converters, including: Notebook Power Adapters Open-Frame SMPS DESCRIPTION The highly integrated SG6842J 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. To avoid acoustic-noise problem, the minimum PWM frequency set above 20kHz. This green-mode function enables the power supply to easily meet international power conservation requirements. To further reduce power consumption, SG6842J is manufactured by using the BiCMOS process. This allows the lowest start-up current around 8uA, and the operating current is only 4mA. As a result, large start-up resistance can be used. SG6842J integrates frequency jittering function internally. The frequency jittering function helps reduce EMI emission of a power supply with minimum line filters. Also, its built-in synchronized slope compensation achieves stable peak-current-mode control. The proprietary internal line compensation ensures constant output power limit over a wide AC input voltages, from 90VAC to 264VAC. SG6842J 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 occurs. PWM output is disabled till VDD drops below the UVLO lower limit. Then, the controller starts up again. As long as VDD exceeds about 24V, the internal OVP circuit is triggered. An external NTC thermistor can be applied for over-temperature protection. For OVP and OTP, the protection mode can be chosen to be latch off or auto recovery. SG6842J is available in an 8-pin DIP or SOP package. TYPICAL APPLICATION © System General Corp. Version 1.4(IAO33.0015.B4) -1- www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller MARKING DIAGRAMS PIN CONFIGURATION F: L = OTP Latch, C = OTP auto-recovery T: D = DIP, S = SOP P : Z =Lead Free + ROHS Compatible Null=regular package XXXXXXX: Wafer Lot YY: Year; WW: Week V: Assembly Location SG6842JFTP XXXXXXXYYWWV GND GATE FB VDD VIN RI SENSE RT ORDERING INFORMATION Part Number OTP Latch Package SG6842JLSZ Yes 8-Pin SOP (Lead Free) SG6842JLDZ Yes 8-Pin DIP (Lead Free) SG6842JCSZ No 8-Pin SOP (Lead Free) SG6842JCDZ No 8-Pin DIP (Lead Free) PIN DESCRIPTIONS Pin No. Symbol 1 GND Function Description Ground Ground. The signal from the external compensation circuit is fed into this pin. The PWM duty cycle is 2 FB Feedback determined in response to the signal from this pin and the current-sense signal from Pin 6. If FB voltage exceeds a threshold, the internal protection circuit will disable 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 3 VIN Start-Up Input current requirement of the SG6842J is very small, a large start-up resistance can be used to minimize power loss. Under normal operation, this pin is also used to detect the line voltage. As a result, constant output power limit over a universal AC input range can be achieved. 4 5 RI RT Reference Setting Temperature Detection 6 SENSE Current Sense 7 VDD Power Supply 8 GATE Driver Output © System General Corp. Version 1.4(IAO33.0015.B4) A resistor connected from the RI pin to GND pin will provide the SG6842J with a constant current source. This determines the center PWM frequency. Increasing the resistance will reduce PWM frequency. Using a 26kΩ resistor RI results in a 65kHz center PWM frequency. For over-temperature protection. An external NTC thermistor is connected from this pin to GND pin. The impedance of the NTC will decrease at high temperatures. Once the voltage of the RT pin drops below a fixed limit , PWM output will be 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 will disable PWM output. The totem-pole output driver for the power MOSFET. It is internally clamped below 18V -2- www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller BLOCK DIAGRAM © System General Corp. Version 1.4(IAO33.0015.B4) -3- www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit VDD Supply Voltage Test Condition 25 V VIN Input Terminal 30 V VFB Input Voltage to FB Pin -0.3 to 7V V VSENSE Input Voltage to SENSE Pin -0.3 to 7V V VRT Input Voltage to RT Pin -0.3 to 7V V VRI Input Voltage to RI Pin -0.3 to 7V V at TA < 50°C DIP 800 SOP 400 DIP 82.5 SOP 141 PD Power Dissipation RΘ J-A Thermal Resistance TJ Operating Junction Temperature -40 to +125 °C TSTG Storage Temperature Range -55 to +150 °C TL Lead Temperature (Soldering) Junction-Air 10 sec DIP 260 10 sec SOP 230 mW °C/W °C *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 JUNCTION TEMPERATURE: -30°C ~ 85°C* *For proper operation ELECTRICAL CHARACTERISTICS (VDD = 15V, TA = 25°C, unless noted) VDD Section Symbol Parameter VOP Continuously Operating Voltage VTH-ON Turn-on Threshold Voltage VTH-OFF Turn-off Voltage Test Condition Min. Typ. Max. Unit 22 V 15.5 16.5 17.5 V 9.5 10.5 11.5 V 30 uA 4 5 mA 24.2 25.2 VDD = 15V, IDD-ST Start-Up Current RI = 26 kΩ GATE with 1nF to GND IDD-OP Operating Supply Current VDD-OVP VDD Over Voltage Protection TVDD-OVP VDD OVP Debounce Time GATE open 23.2 RI = 26kΩ 100 V usec RI Section Symbol Parameter RINOR RI Operating Range RIMAX Max. RI value for Protection 230 kΩ RIMIN Min. RI value for Protection 10 kΩ © System General Corp. Version 1.4(IAO33.0015.B4) Test Condition Min. Typ. 15.5 -4- Max. 36 Unit kΩ www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller Oscillator Section Symbol FOSC Parameter Normal PWM Frequency Test Condition Center Frequency Jitter Range RI = 26kΩ Min. Typ. Max. 62 65 68 ±3.7 ±4.2 ±4.7 Unit kHz TJTR Jittering Period RI = 26kΩ 3.9 4.4 4.9 FOSC-G-MIN Green-Mode Min. Frequency RI = 26kΩ 18 22 25 mS kHz FDV Frequency Variation Versus VDD Deviation VDD = 11.5V to 20V 5 % FDT Frequency Variation Versus Temp. Deviation TA = -30 to 85 ℃ 5 % Feedback Input Section Symbol Parameter Test Condition Min. Typ. Max. Unit AV FB Input to Current Comparator Attenuation @Green mode 1/4.5 1/4 1/3.5 V/V 7 kΩ ZFB Input Impedance VHGH Output High Voltage VFB-OL FB open-loop trigger level TLPS FB open-loop Protection Delay 4 FB pin open 5.5 V 5 RI = 26kΩ 50 56 5.4 V 62 mS VN Green-Mode Entry FB Voltage 1.9 2.1 2.3 V VG Green-Mode Ending FB Voltage VN-0.6 VN-0.5 VN-0.4 V FG-TEST Burst-Mode test Frequency IZERO PWM OFF FB Voltage FOSC-G-MIN VG+20mV KHz +0.5 1.5 mA Current Sense Section Symbol Parameter ZCS Input Impedance VTH80 Threshold voltage for current limit IVIN = 80uA, RI = 26kΩ VTH160 Threshold voltage for current limit IVIN = 160uA, RI = 26kΩ TPD Propagation Delay to GATE Output TLEB Leading Edge Blanking Time VSLOPE Slope Compensation © System General Corp. Version 1.4(IAO33.0015.B4) Test Condition Min. Typ. Max. 12 SENSE=2KΩ, DCYMAX -5- Duty 0.81 = 0.84 Unit kΩ 0.87 V VTH80 VTH80 VTH80 -0.085 -0.07 -0.055 100 200 nS 260 360 460 nS 0.34 0.37 0.41 V V www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller GATE Section Symbol Parameter DCYMAX Maximum Duty Cycle Test Condition Min. Typ. Max. Unit 80 85 90 % VOL Output Voltage Low VDD =15V, IO = 50mA VOH Output Voltage High VDD =12V, IO = 50mA 8V TR Rising Time VDD =15V, CL = 1nF 150 250 350 nS TF Falling Time VDD =15V, CL = 1nF 30 50 90 nS IO Peak Output Current VDD =15V, GATE=6V 230 VCLAMP Gate Output Clamping Voltage VDD = 22V 18 19 V Typ. Max. Unit 1.5 V V mA RT Section Symbol Parameter Test Condition Min. IRT Output Current of RT pin RI = 26kΩ 67 70 73 uA VOTP-STOP Trigger Voltage for Over-temperature Protection 1.015 1.05 1.085 V TOTP-LATCH Over-temperature Latch-off Debounce. 60 100 140 uS © System General Corp. Version 1.4(IAO33.0015.B4) RI = 26kΩ,VRT<0.7V -6- www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller TYPICAL CHARACTERISTICS Operati on Current (I DDop) vs Temperature Start-up Current (I DDst) vs Temperature 5.000 20.000 4.500 I DDop (mA) I DDst (uA) 18.000 16.000 14.000 4.000 3.500 3.000 12.000 2.500 10.000 -40 -25 -10 5 20 35 50 65 80 95 110 -40 125 -25 -10 5 20 Temperature (℃) 50 65 80 95 110 125 80 95 110 125 110 125 RI vol tage (VRI ) vs Temperature VDD vs I DD 25 1.400 20 1.350 VRI (V) I DD (uA) 35 Temperature (℃) 15 10 1.300 1.250 5 1.200 0 0 2 4 6 8 10 12 14 -40 16 -25 -10 5 35 50 65 PWM Frequency (Fosc) vs Temperature On Threshol d Vol tage (VTHon) vs Temperature 17.0 66.000 16.8 65.600 Fosc (Khz) VTHon (V) 20 Temperature (℃) VDD (V) 16.6 16.4 65.200 64.800 64.400 16.2 64.000 16.0 -40 -25 -10 5 20 35 50 65 80 95 110 -40 125 © System General Corp. Version 1.4(IAO33.0015.B4) -25 -10 5 20 35 50 65 80 95 Temperature (℃) Temperature (℃) -7- www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller Votp,stop vs Temperature 90.000 1.100 86.000 1.080 Votp-l atch-of f (V) DCY (%) M ax. DUTY (DCY) vs Temperature 82.000 78.000 74.000 1.060 1.040 1.020 1.000 70.000 -40 -25 -10 5 20 35 50 65 80 95 110 -40 125 -25 -10 5 25.000 80.000 20.000 76.000 I rt (uA) Fose-green (Khz) 35 50 65 80 95 110 125 95 110 125 110 125 Output Current of pi n RT (I rt) vs Temperature Green-mode mi n. Frequency vs Temperature 15.000 10.000 72.000 68.000 64.000 5.000 60.000 0.000 -40 -25 -10 5 20 35 50 65 80 95 110 -40 125 -25 -10 5 20 35 50 65 80 Temperature (℃) Temperature (℃) VSENSE vs I VI N Of f Threshol d Vol tage (VTHof f ) vs Temperature 0.89 11.0 0.84 10.8 0.79 VTHof f (V) VSENSE (V) 20 Temperature (℃) Temperature (℃) 0.74 0.69 0.64 0.59 0.54 10.6 10.4 10.2 10.0 9.8 0.49 0.44 9.6 0 40 80 120 160 200 240 280 320 360 -40 IVIN(uA) © System General Corp. Version 1.4(IAO33.0015.B4) -25 -10 5 20 35 50 65 80 95 Temperature (℃) -8- www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller 61kHz to 69kHz for a center frequency 65kHz. The frequency jittering function helps reduce EMI emission of a power supply with minimum line filters. OPERATION DESCRIPTION Start-Up Current The typical start-up current is only 8uA. This allows a high resistance, low-wattage start-up resistor to be used, to minimize power loss. A 1.5 MΩ, 0.25W, start-up resistor and a 10uF/25V VDD hold-up capacitor would be sufficient for an AC/DC adapter with a universal input range. Operating Current The required operating current has been reduced to 4mA. This results in higher efficiency and reduces the VDD hold-up capacitance requirement. IRT = 70uA RI (kΩ ) • 26 -------------------------------(2) Leading Edge Blanking Each time the power MOSFET is switched on, a turn-on spike will inevitably occur 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 it cannot switch off the gate drive. Under-Voltage Lockout (UVLO) 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 problem, the minimum PWM frequency set above 20kHz. This green-mode function dramatically reduces power consumption under light-load and zero-load conditions. Power supplies using a SG6842J controller can easily meet even the most restrictive international regulations regarding standby power consumption. The turn-on/turn-off thresholds are fixed internally at 10.5V/16.5V. To enable a SG6842J controller during start-up, the hold-up capacitor must first be charged to 16.5V through the start-up resistor. The hold-up capacitor will continue to supply VDD before energy can be delivered from the auxiliary winding of the main transformer. VDD must not drop below 10.5V during this start-up process. This UVLO hysteresis window ensures that the hold-up capacitor can adequately supply VDD during start-up. Oscillator Operation Gate Output / Soft Driving A resistor connected from the RI pin to GND pin generates a constant current source for the SG6842J controller. This current is used to determine the center PWM frequency. Increasing the resistance will reduce PWM frequency. Using a 26kΩ resistor RI results in a corresponding 65kHz PWM frequency. The relationship between RI and the switching frequency is: The SG6842J 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 in order to protect the power MOSFET transistors from any harmful over-voltage gate signals. A soft driving waveform is implemented to minimize EMI. fPWM = 1690 RI (kΩ ) (kHz) ---------------------------- (1) Slope Compensation SG6842J also integrates frequency jittering function internally. The frequency variation ranges from around © System General Corp. Version 1.4(IAO33.0015.B4) -9- The sensed voltage across the current sense resistor is used for peak-current-mode control and cycle-by-cycle current limiting. The built-in slope compensation www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller function improves power supply stability and prevents peak-current-mode control from causing sub-harmonic oscillations. Within every switching cycle, the SG6842J controller produces a positively sloped, synchronized ramp signal. Constant Output Power Limit Limited Power Control The FB voltage will increase every time the output of the power supply is shorted or over-loaded. If the FB voltage remains higher than a built-in threshold for longer than TLPS, PWM output will then be turned off. As PWM output is turned off, the supply voltage VDD will also begin decreasing. When the SENSE voltage across the sense resistor RS reaches the threshold voltage, the output GATE drive will be turned off following a small propagation delay TPD. This propagation delay will result in an additional current proportional to TPD*VIN/LP. The propagation delay is nearly constant regardless of the input line voltage VIN. Higher input line voltages will result in larger additional currents. Thus, under high input-line voltages the output power limit will be higher than under low input-line voltages. When VDD goes below the turn-off threshold (eg, 10.5V) the controller will be totally shut down. VDD will be charged up to the turn-on threshold voltage of 16.5V through the start-up resistor until PWM output is restarted. This protection feature will continue to be activated as long as the over-loading condition persists. This will prevent the power supply from overheating due to over loading conditions. The output power limit variation can be significant over a wide range of AC input voltages. To compensate for this, the threshold voltage is adjusted by the current IIN. Since the pin VIN is connected to the rectified input line voltage through the start-up resistor, a higher line voltage will result in a higher current IIN through the pin VIN. For the SG6842J family, the built-in latch function provides a versatile protection feature that does not require external components. See ordering information for a detailed description. To reset the latch circuit, it is necessary to disconnect the AC line voltage of the power supply. The threshold voltage decreases if the current IIN increases. A small threshold voltage will force the output GATE drive to terminate earlier, thus reducing total PWM turn-on time, and making the output power equal to that of the low line input. This proprietary internal compensation feature ensures a constant output power limit over a wide range of AC input voltages (90VAC to 264VAC). An external NTC thermistor can be connected from the RT pin to ground. A fixed current IRT is sourced from the RT pin. Because the impedance of the NTC will decrease at high temperatures, when the voltage of the RT pin drops below 1.065V, PWM output will be disabled. The RT pin output current is related to the PWM frequency programming resistor RI VDD Over-voltage Protection Noise Immunity VDD over-voltage protection has been built in to prevent damage due to over voltage conditions. When the voltage VDD exceeds the internal threshold due to abnormal conditions, PWM output will be turned off. Over-voltage conditions are usually caused by open feedback loops. Noise from the current sense or the control signal may cause significant pulse width jitter, particularly in continuous-conduction mode. Slope compensation helps alleviate this problem. Good placement and layout practices should be followed. The designer should avoiding long PCB traces and component leads. Compensation and filter components should be located near the SG6842J. Finally, increasing the power-MOS gate resistance is advised. © System General Corp. Version 1.4(IAO33.0015.B4) - 10 - Protection Latch Circuit Thermal Protection www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller PACKAGE INFORMATION 8PINS-DIP(D) D Θ° 5 E1 8 e B E A A1 A2 4 1 L b1 b e Dimensions Symbol Millimeters Min. Typ. A Max. Inches Min. Typ. 5.334 A1 0.381 A2 3.175 0.210 0.015 3.302 3.429 0.125 0.130 b 1.524 0.060 b1 0.457 0.018 D 9.017 E E1 Max. 9.271 10.160 0.355 7.620 6.223 6.350 L 2.921 eB θ˚ 0.365 0.135 0.400 0.300 6.477 0.245 0.250 3.302 3.810 0.115 0.130 0.150 8.509 9.017 9.525 0.335 0.355 0.375 0˚ 7˚ 15˚ 0˚ 7˚ 15˚ e 2.540 © System General Corp. Version 1.4(IAO33.0015.B4) 0.255 0.100 - 11 - www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller 8PINS-SOP(S) 8 C 5 H E F 1 4 b e D Θ A1 L A Dimensions Symbol Millimeter Min. Typ. Max. Inch Min. A A1 b c D E e F H L θ˚ 1.346 0.101 1.752 0.254 0.053 0.004 0.406 0.203 4.648 3.810 1.016 5.791 0.406 0° © System General Corp. Version 1.4(IAO33.0015.B4) 1.270 0.381X45° Typ. Max. 0.069 0.010 0.016 0.008 4.978 3.987 1.524 0.183 0.150 0.040 6.197 1.270 8° 0.228 0.016 0° - 12 - 0.050 0.015X45° 0.196 0.157 0.060 0.244 0.050 8° www.sg.com.tw Feb. 13, 2006 Product Specification SG6842J Highly-Integrated Green-Mode PWM Controller DISCLAIMERS LIFE SUPPORT System General’s products are not designed to be used as components in devices intended to support or sustain human life. Use of System General’s products in components intended for surgical implant into the body, or other applications in which failure of System General’s products could create a situation where personal death or injury may occur, is not authorized without the express written approval of System General’s Chief Executive Officer. System General will not be held liable for any damages or claims resulting from the use of its products in medical applications. MILITARY System General's products are not designed for use in military applications. Use of System General’s products in military applications is not authorized without the express written approval of System General’s Chief Executive Officer. System General will not be held liable for any damages or claims resulting from the use of its products in military applications. RIGHT TO MAKE CHANGES System General reserves the right to change this document and/or this product without notice. Customers are advised to consult their System General sales representative before ordering. © System General Corp. Version 1.4(IAO33.0015.B4) - 13 - www.sg.com.tw Feb. 13, 2006