SG6741

Product Specification Highly-Integrated Green-Mode PWM Controller SG6741 linearly decrease the switching frequency at light-load conditions. To avoid acoustic-noise problems, the minimum PWM frequency is set above 22KHz. This green-mode function enables the power supply to meet international power conservation requirements. With the internal high-voltage start-up circuitry, the power loss due to bleeding resistors is also eliminated. To further reduce power consumption, SG6741 is manufactured using the BiCMOS process, which allows operating current as low as 4mA. SG6741 integrates a frequency-hopping function that helps reduce EMI emission of a power supply with minimum line filters. 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 range of AC input voltages, from 90VAC to 264VAC. SG6741 provides many protection functions. In addition to cycle-by-cycle current limiting, the internal open-loop protection circuit ensures safety when an open-loop or output short-circuit failure occurs. PWM output is disabled until VDD drops below the UVLO lower limit; then the controller starts again. As long as VDD exceeds about 26V, the internal OVP circuit is triggered. SG6741 is available in an 8-pin DIP or SOP package. FEATURES High-voltage start-up Low operating current (4mA) Linearly decreasing PWM frequency to 22kHz Frequency hopping to reduce EMI emission Peak-current-mode control Cycle-by-cycle current limiting Leading-edge blanking S ynchronized slope compensation Gate output maximum voltage clamp (18V) VDD over-voltage protection (auto restart) VDD under-voltage lockout (UVLO) Internal open-loop protection Constant power limit (full AC input range) APPLICATIONS General-purpose switch-mode power flyback power converters, including: Power adapters Open-frame SMPS supplies and DESCRIPTION The highly integrated SG6741 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 TYPICAL APPLICATION © System General Corp. Version 1.2.1 (IAO33.0047.B2) -1- www.sg.com.tw • www.fairchildsemi.com September 19, 2007 Product Specification Highly-Integrated Green-Mode PWM Controller SG6741 PIN CONFIGURATION MARKING INFORMATION T: S = SOP P: Z =Lead Free Null=regular package XXXXXXXX: Wafer Lot Y: Year; WW: Week V: Assembly Location GND FB NC HV GATE VDD SENSE RI SG6741TP XXXXXXXXYWWV ORDERING INFORMATION Part Number SG6741SZ Pb-Free Package SOP-8 PIN DESCRIPTIONS Pin No. Symbol 1 2 3 4 GND FB NC HV Function Ground Feedback NA Start-up Input 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 on this pin and the current-sense signal on the SENSE pin. NC pin. For start-up, this pin is pulled high to the line input or bulk capacitor via resistors. A resistor connected from the RI pin to GND pin provides the SG6741 with a constant current source. This determines the center PWM frequency. Increasing the resistance reduces PWM frequency. Using a 26KΩ resistor (RI) results in a 65kHz center PWM frequency. Current sense. The sensed voltage is used for peak-current-mode control and cycle-by-cycle current limiting. Power supply. The internal protection circuit disables PWM output as long as VDD exceeds the OVP trigger point. The totem-pole output driver. Soft driving waveform is implemented for improved EMI. 5 RI Reference Setting 6 7 8 SENSE VDD GATE Current Sense Power Supply Driver Output © System General Corp. Version 1.2.1 (IAO33.0047.B2) -2- www.sg.com.tw • www.fairchildsemi.com September 19, 2007 Product Specification Highly-Integrated Green-Mode PWM Controller SG6741 BLOCK DIAGRAM © System General Corp. Version 1.2.1 (IAO33.0047.B2) -3- www.sg.com.tw • www.fairchildsemi.com September 19, 2007 Product Specification Highly-Integrated Green-Mode PWM Controller SG6741 ABSOLUTE MAXIMUM RATINGS Symbol VDD VHV VL PD RΘJA TJ TSTG TL ESD Parameter Supply Voltage Input Voltage to HV Pin Input Voltage to FB, SENSE, Pin Power Dissipation, TA < 50°C Thermal Resistance, Junction-to-Air Operating Junction Temperature Storage Temperature Range Lead Temperature (Wave soldering or IR, 10 seconds) Electrostatic Discharge Capability, Machine Model (All pins except HV pin) Value 30 500 -0.3 to 7 DIP SOP DIP SOP -40 to +125 -55 to +150 260 250 800 400 82.5 141 Unit V V V mW mW °C/W °C/W °C °C °C KV V Electrostatic Discharge Capability, Human Body Model (All pins except HV pin) 3 *All voltage values, except differential voltages, are given with respect to the GND pin. *Stresses above those listed 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 12V ≤ VDD ≤ 25V; -20°C ≤ TA ≤ 85°C, unless otherwise noted. VDD Section Symbol VDD-OP VDD-ON VDD-OFF IDD-ST IDD-OP IDD-OLP VDD-OLP VDD-OVP tD-VDDOVP Parameter Continuously Operating Voltage Start Threshold Voltage Minimum Operating Voltage Start-up Current Operating Supply Current Internal Sink Current IDD-OLP Off Voltage VDD Over-Voltage Protection Test Condition Min. 15.5 9.5 Typ. 16.5 10.5 Max. 22 17.5 11.5 30 Unit V V V µA mA µA V V µs VDD-ON – 0.16V VDD = 15V, GATE open VDD-OLP +0.1V (Auto Restart) 50 6.5 25 100 4 70 7.5 26 180 5 90 8.0 27 260 VDD Over-Voltage-protection Debounce Time (Auto Restart) HV Section Symbol IHV IHV-LC Parameter Supply Current Drawn from Pin HV Leakage Current After Start-up Test Condition VAC=90V(VDC=120V)； VDD=0V With Auxiliary Supply HV = 500V, VDD = 15V Min. Typ. 2 1 Max. Unit mA 20 µA © System General Corp. Version 1.2.1 (IAO33.0047.B2) -4- www.sg.com.tw • www.fairchildsemi.com September 19, 2007 Product Specification Highly-Integrated Green-Mode PWM Controller SG6741 Oscillator Section Symbol FOSC tHOP FOSC-G FDV FDT Parameter Frequency in Nominal Mode Hopping Period Green-Mode Frequency Frequency Variation vs. VDD Deviation Frequency Variation vs. Temp. Deviation Test Condition Center Frequency Hopping Range Min. 62 ±3.7 18 Typ. 65 ±4.2 4.4 22 Max. 68 ±4.7 25 5 5 Unit kHz ms kHz % % VDD=11V to 22V TA=-20 to 85℃ Feedback Input Section Symbol AV ZFB VFB-OPEN VFB-OLP tD-OLP VFB-N VFB-G Parameter Input Voltage to Current-Sense Attenuation Input Impedance FB Output High Voltage FB Open-Loop Trigger Level Delay Time, 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 Max. 1/2.75 7 Unit V/V kΩ V V ms V V FB Pin Open RI=26kΩ 5.5 3.7 50 1.9 4.0 56 2.1 VFB-N -0.5 4.3 62 2.3 PWM Frequency FOSC FOSC-G VFB-G VFB-N VFB Current-Sense Section Symbol ZSENSE VSTHFL VSTHVA tPD tLEB VS-SCP tD-SSCP Parameter Input Impedance Current Limit Flatten Threshold Voltage Current Limit Valley Threshold Voltage Delay to Output Leading-Edge Blanking Time Threshold Voltage for SENSE Short-Circuit Protection Delay Time for SENSE Short-Circuit Protection Test Condition Min. 0.87 Typ. 12 0.90 0.22 100 350 0.15 Max. 0.93 0.26 200 425 Unit KΩ V V ns ns V µs VSTHFL–VSTHVA 0.18 275 VSENSE