SG6901A

Product Specification PFC / Flyback PWM Controller SG6901A very few external components to achieve versatile protections. It is available in a 20-pin SOP package. The patented interleave-switching feature synchronizes the PFC and PWM stages and reduces switching noise. For PFC stage, the proprietary multi-vector control scheme provides a fast transient response in a low-bandwidth PFC loop, in which the overshoot and undershoot of the PFC voltage are clamped. If the feedback loop is broken, the SG6901A shuts off PFC to prevent extra-high voltage on output. Programmable two-level output voltage control reduces the PFC output voltage at low line input to increase the efficiency of the power supply. For the flyback PWM, the synchronized slope compensation ensures the stability of the current loop under continuous-conduction-mode operation. Built-in line-voltage compensation maintains constant output-power limit. Hiccup operation during output overloading is also guaranteed. In addition, SG6901A provides protection functions, such as brownout and RI pin open/short protection. FEATURES OVERVIEW Interleaved PFC/PWM switching Low start-up and operating current Innovative switching charge multiplier-divider Multi-vector control for improved PFC output transient response Average-current-mode control for PFC Programmable two-level PFC output voltage PFC over-voltage and under-voltage protections PFC and PWM feedback open-loop protection Cycle-by-cycle current limiting for PFC/PWM Slope compensation for PWM Constant power limit for PWM Brownout protection Over-temperature protection (OTP) APPLICATIONS Switching Power Supplies with Active PFC and Standby Power High-Power Adaptors DESCRIPTION The highly integrated SG6901A is designed for power supplies with boost PFC and flyback PWM. It requires Typical Application © System General Corp. Version 1.0.1 (IAO33.0062.B0) -1- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A MARKING DIAGRAMS PIN CONFIGURATION SG6901A TP XXXXXXXXYWWV T: S=SOP P : Z=Lead Free Null=regular package XXXXXXXX: Wafer Lot Y: Year; WW: Week V: Assembly Location ORDERING INFORMATION Part Number SG6901ASZ Pb-Free Package 20-pin SOP © System General Corp. Version 1.0.1 (IAO33.0062.B0) -2- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A PIN DESCRIPTIONS Name VRMS Pin No. 1 Type Line-Voltage Detection Function Line voltage detection. The pin is used for PFC multiplier, RANGE control of PFC output voltage, and brownout protection. For brownout protection, the controller is disabled after a delay time when the VRMS voltage drops below a threshold. Reference setting. One resistor connected between RI and ground determines the switching frequency. The switching frequency is equal to [1560 / RI] KHz, where RI is in KΩ. For example, if RI is equal to 24KΩ, the switching frequency is 65KHz. This pin supplies an over-temperature protection signal. A constant current is output from this pin. An external NTC thermistor must be connected from this pin to ground. The impedance of the NTC thermistor decreases whenever the temperature increases. Once the voltage of the OTP pin drops below the OTP threshold, the SG6901A is disabled. This is the output of the PFC current amplifier. The signal from this pin is compared with an internal sawtooth and determines the pulse width for PFC gate drive. The inverting input of the PFC current amplifier. Proper external compensation circuits result in excellent input power factor via average-current-mode control. The non-inverting input of the PFC current amplifier and the output of multiplier. Proper external compensation circuits will result in excellent input power factor via average-current-mode control. The peak-current setting for PFC. The control input for voltage-loop feedback of PWM stage. It is internally pulled high through a 6.5kΩ resistance. Usually an external opto-coupler from secondary feedback circuit is connected to this pin. The current-sense input for the flyback PWM. Via a current sense resistor, this pin provides the control input for peak-current-mode control and cycle-by-cycle current limiting. Signal ground. During startup, the SS pin will charge an external capacitor with a 50µA (RI=24KΩ) constant current source. The voltage on FBPWM will be clamped by SS during startup. In the event of a protection condition occurring and/or PWM being disabled, the SS pin will be quickly discharged. The totem-pole output drive for the Flyback PWM MOSFET. This pin is internally clamped under 17V to protect the MOSFET. Power ground. The totem-pole output drive for the PFC MOSFET. This pin is internally clamped under 17V to protect the MOSFET. The power supply pin. Two-level output voltage setting for PFC. The PFC output voltage at low line can be reduced to improve efficiency. The RANGE pin has high impedance whenever the VRMS voltage is lower than a threshold. The PFC stage over voltage input. The comparator disables the PFC output driver if the voltage at this input exceeds a threshold. This pin can be connected to FBPFC or it can be connected to the PFC boost output through a divider network. The feedback input for PFC voltage loop. The inverting input of PFC error amplifier. This pin is connected to the PFC output through a divider network. The error amplifier output for PFC voltage feedback loop. A compensation network (usually a capacitor) is connected between this pin and ground. A large capacitor value results in a narrow bandwidth and improves the power factor. This input is used to provide current reference for the multiplier. RI 2 Oscillator Setting OTP 3 Over Temperature Protection Output for PFC Current Amplifier Inverting Input for PFC Current Amplifier Non-inverting Input for PFC Current Amplifier Peak Current Limit Setting for PFC PWM Feedback Input PWM Current Sense Ground PWM Soft-Start IEA 4 IPFC 5 IMP ISENS E FBPW M 6 7 8 IPWM AGND SS 9 10 11 OPWM GND OPFC VDD RANGE 12 13 14 15 16 PWM Gate Drive Ground PFC Gate Drive Supply PFC Output Voltage Control PFC Over-Voltage Input Voltage Feedback Input for PFC Error Amplifier Output for PFC Voltage Feedback Loop Input AC Current OVP 17 FBPFC 18 VEA 19 IAC 20 © System General Corp. Version 1.0.1 (IAO33.0062.B0) -3- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A BLOCK DIAGRAM © System General Corp. Version 1.0.1 (IAO33.0062.B0) -4- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A ABSOLUTE MAXIMUM RATINGS Symbol VVDD IAC VHigh VLow PD TJ TSTG RθJC TL VESD,HBM VESD,MM Parameter DC Supply Voltage* Input AC Current OPWM, OPFC, IAC Others Power Dissipation at TA < 50°C Operating Junction Temperature Storage Temperature Range Thermal Resistance (Junction-to-Case) Lead Temperature (Wave Soldering or Infrared, 10 Seconds) Electrostatic Discharge Capability, Human Body Model Electrostatic Discharge Capability, Machine model Value 25 2 -0.3 to +25.0 -0.3 to +7.0 1.15 -40 to +125 -55 to +150 23.64 260 4.5 250 Unit V mA V V W °C °C °C/W °C KV V *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=25°C unless otherwise noted. VDD Section Symbol VDD-OP IDD-ST IDD-OP VDD-ON VDD-OFF VDD-OVP tD-VDDOVP Parameter Continuously Operating Voltage Start-up Current Operating Current Start Threshold Voltage Minimum Operating Voltage VDD OVP Threshold Debounce Time of VDD OVP Test Conditions 0V < VDD < VDD-ON VDD=15V; OPFC, OPWM open; RI=24KΩ Min. Typ. 10 6 Max. 20 25 10 13 11 25.5 25 Unit V µA mA V V V µs 11 9 23.5 8 12 10 24.5 Oscillator Section Symbol FOSC RI RIOPEN RISHORT Parameter PWM Frequency RI Pin Resistance Range RI Pin Open Protection If RI > RIopen , SG6901A Turns Off RI Pin Short Protection If RI < RIshort , SG6901A Turns Off Test Conditions RI=24KΩ Min. 62 15.6 Typ. 65 Max. 68 47.0 Unit KHz KΩ KΩ KΩ 200 2 © System General Corp. Version 1.0.1 (IAO33.0062.B0) -5- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A VRMS for UVP and RANGE Symbol VRMS-UVP-1 VRMS-UVP-2 tD-PWM tUVP VRMS-H VRMS-L tRANGE VOL IOH Parameter RMS AC Voltage Under-Voltage Protection Threshold (with tUVP delay) Recovery Level on VRMS When UVP Occurs, Interval from PFC Off to PWM Off Under-Voltage Protection Delay Time* High VRMS Threshold for RANGE Comparator Low VRMS Threshold for RANGE Comparator Range-Enable Delay Time Output Low Voltage of RANGE Pin Output High Leakage Current of RANGE Pin Test Conditions Min. 0.75 VRMS-UVP-1 + 0.16V tUVP-Min+9 150 1.90 1.55 140 Typ. 0.8 VRMS-UVP-1 + 0.18V Max. 0.85 VRMS-UVP-1 + 0.2V tUVP-Min+1 4 Unit V V ms ms V V ms V nA 195 1.95 1.60 170 240 2.00 1.65 200 0.5 50 Io=1mA RANGE=5V * No delay for start-up. PFC Stage Voltage Error Amplifier Symbol VREF Av Zo OVPPFC △OVPPFC tOVP-PFC VFBPFC-H GFBPFC-H VFBPFC-L GFBPFC-L IFBPFC-L IFBPFC-H UVPFBPFC tUVP-FBPFC Parameter Reference Voltage Open-Loop Gain Output Impedance PFC Over-Voltage Protection (OVP Pin) PFC Feedback Voltage Protection Hysteresis Debounce Time of PFC OVP Clamp-High Feedback Voltage Clamp-High Gain Clamp-Low Feedback Voltage Clamp-Low Gain Maximum Source Current Maximum Sink Current PFC Feedback Under-Voltage Protection Debounce Time of PFC UVP Test Conditions Min. 2.95 Typ. 3.00 60 110 Max. 3.05 Unit V dB KΩ 3.20 60 40 3.10 2.75 1.5 70 0.35 40 3.25 90 70 3.15 0.5 2.85 6.5 2.0 110 0.40 70 3.30 120 120 3.20 2.90 V mV µs V µA/mV V mA/mV mA µA 0.45 120 V µs Current Error Amplifier Symbol VOFFSET AI BW CMRR VOUT-HIGH VOUT-LOW IMR1, IMR2 IL IH Parameter Input Offset Voltage ((-) > (+)) Open-Loop Gain Unit Gain Bandwidth Common Mode Rejection Ratio Output High Voltage Output Low Voltage Reference Current Source Maximum Source Current Maximum Sink Current Test Conditions Min. Typ. 8 60 1.5 Max. Unit mV dB MHz dB V VCM=0 to +1.5V 3.2 70 0.2 V µA mA mA RI=24KΩ (IMR=20+IRI•0.8) 50 3 0.25 70 © System General Corp. Version 1.0.1 (IAO33.0062.B0) -6- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A Peak Current Limit Symbol IP VPK tPD-PFC tLEB-PFC Parameter Constant Current Output Peak Current Limit Threshold Voltage Cycle-by-Cycle Limit (VSENSE < VPK) Propagation Delay Leading-Edge Blanking Time Test Conditions RI=24KΩ VRMS=1.05V VRMS=3V Min. 90 0.15 0.35 270 Typ. 100 0.20 0.40 350 Max. 110 0.25 0.45 200 450 Unit µA V V ns ns Multiplier Symbol IAC IMO–max IMO-1 IMO–2 VIMP Parameter Input AC Current Maximum Multiplier Current Output Multiplier Current Output (Low-line, High-power) Multiplier Current Output (High-line, High-power) Voltage of IMP Open Test Conditions Multiplier Linear Range RI=24KΩ VRMS=1.05V; IAC=90µA; VEA=7.5V; RI=24KΩ VRMS=3V; IAC=264µA; VEA=7.5V; RI=24KΩ Min. 0 Typ. 250 Max. 360 Unit µA µA 200 65 3.4 250 85 3.9 280 µA µA 4.4 V PFC Output Driver Symbol VZ VOL-PFC tPFC VOH-PFC tR-PFC tF-PFC DCYMAX Parameter Output Voltage Maximum (Clamp) Output Voltage Low Interval OPFC Lags Behind OPWM at Start-up Output Voltage High Rising Time Falling Time Maximum Duty Cycle Test Conditions VDD=20V VDD=15V; IO=100mA Min. Typ. 16 Max. 18 1.5 Unit V V ms V 9.0 VDD=13V; IO=100mA VDD=15V; CL=5nF; O/P=2V to 9V VDD=15V; CL=5nF; O/P=9V to 2V 8 40 40 93 11.5 14.0 70 60 120 110 98 ns ns % PWM Stage FBPWM Symbol Av-PWM ZFB IFB FBOPEN-LOOP tOPEN-PWM tOPEN-PWM-Hiccup Parameter FB to Current Comparator Attenuation Input Impedance Maximum Source Current PWM Open-Loop Protection voltage PWM Open-Loop Protection Delay Time Interval of PWM Open-Loop Protection Reset Test Conditions Min. 2.5 4 0.8 4.2 45 450 Typ. 3.1 5 1.2 4.5 56 600 Max. 3.5 7 1.5 4.8 70 750 Unit V/V KΩ mA V ms ms © System General Corp. Version 1.0.1 (IAO33.0062.B0) -7- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification PFC / Flyback PWM Controller SG6901A PWM-Current Sense Symbol tPD-PWM VLIMIT-1 VLIMIT-2 tLEB-PWM △VSLOPE Parameter Propagation Delay to Output Peak Current Limit Threshold Voltage1 Peak Current Limit Threshold Voltage2 Leading-Edge Blanking Time Slope Compensation Test Conditions VDD=15V,OPWM