OB2202CPA

OB2202 Quasi-Resonant Flyback PWM Controller Product Specification GENERAL DESCRIPTION FEATURES OB2202 is a highly integrated Quasi-Resonant (QR) controller optimized for high performance offline flyback converter applications. At normal load condition, it operates in QR mode with minimum drain voltage switching. To meet the CISPR-22 EMI starting at 150KHz, the maximum switching frequency is internally limited to 130KHz. It operates in PFM mode for high power conversion efficiency at light load condition. When the loading is very small, the IC operates in ‘Extended Burst Mode’ to minimize the switching loss. As a result, lower standby power consumption and higher conversion efficiency can be achieved. OB2202 offers comprehensive protection coverage including Cycle-by-Cycle Current Limiting, VCC Under Voltage Lockout(UVLO), Programmable Output Over Voltage Protection(OVP), VCC Clamp, Gate Clamp, Over Load Protection(OLP), On-chip Thermal Shutdown, Programmable Soft Start, Programmable Brownout Protection, Programmable Over Power Protection (OPP) Compensation, and External Latch Triggering, Max On-time Limit, etc. OB2202 is offered in SOP-8 and DIP-8 packages. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Multi-Mode Operation Quasi-Resonant Operation at Normal Loading Pulse Frequency Modulation (PFM) Operation at Light Load Burst Mode at No Load Programmable Brownout Protection and Line OVP Protection Excellent OPP Compensation 130KHz Maximum Frequency Limit Internal Minimum T_off for Ringing Suppression 30us Maximum On Time Limit 50us Maximum Off Time Limit Internal Leading Edge Blanking Programmable Soft-start Cycle-by-cycle Current Limiting External Latch Triggering Internal Thermal Shutdown 1A Peak Current Sink/Source Capability Programmable Output OVP APPLICATIONS Offline AC/DC flyback converter for ■ Power Adaptor and Open-frame SMPS ■ LCD Monitor/TV/PC/Set-Top Box Power Supplies ■ NB/DVD/Portable DVD Power Supplies TYPICAL APPLICATION AC OB2202 1 SS BO 8 2 FB DEM 7 3 CS VCC 6 4 GND GATE 5 Rcomp ©On-Bright Electronics Confidential -1- Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller GENERAL INFORMATION Pin Configuration The pin map of OB2202 in DIP8 and SOP8 package is shown as below. SS 1 8 BO FB 2 7 DEM CS 3 6 VCC GND 4 5 GATE Package Dissipation Rating DIP8 SOP8 90 150 X Package A:DIP8 C:SOP8 ©On-Bright Electronics Value 34 V 10 mA -0.3 to 7V -0.3 to 7V -0.3 to 7V -0.3 to 7V -0.3 to 7V o -40 to 150 C o -55 to 150 C o 260 C listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute maximum-rated conditions for extended periods may affect device reliability. otherwise noted. Qusi-Resonant Flyback PWM controller RJA(℃/W) Absolute Maximum Ratings Parameter VCC Zener Clamp Voltage VCC Clamp Continuous Current SS Input Voltage FB Input Voltage CS Input Voltage DEM Input Voltage BO Input Voltage Maximum Operating Junction Temperature TJ Min/Max Storage Temperature Tstg Lead Temperature (Soldering, 10secs) Note: Stresses beyond those Ordering Information Part Number Description 8 Pin DIP, Halogen free in OB2202AP Tube 8 Pin SOP, Halogen free in OB2202CP Tube 8 Pin SOP, Halogen free in OB2202CPA T&R Note: All Devices are offered in Pb-free Package if not OB2202 Package Confidential -2- X X Package Halogen free P:Halogen-free Packing Blank:Tube A: Tape/Reel Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller Marking Information YWWZZZ YWWZZZ OB2202CP OB2202AP s s Y: Year Code Y: Year Code WW: Week Code (01-52) WW: Week Code (01-52) ZZZ: Lot Code ZZZ: Lot Code C: SOP8 A: DIP8 P:Halogen-free P:Halogen-free s: Internal code(Optional) s: Internal code(Optional) TERMINAL ASSIGNMENTS Pin Num Pin Name I/O 1 SS I/O 2 FB I/O 3 4 5 6 CS GND GATE VCC I P O P 7 DEM I/O 8 BO I/O ©On-Bright Electronics Description Multi-functional pin. One function is for soft-start programming by connecting a capacitor from SS to GND. Another function is for external latch triggering by pulling SS up to a voltage higher than 3.8V. Feedback input pin. PWM duty cycle is determined by voltage level into this pin and current-sense signal level at Pin 3. The voltage level at this pin also controls the mode of operation in one of the three modes: quasi-resonant (QR), pulse frequency modulation mode (PFM) and burst mode (BM). Current sense input. Ground for internal circuitry. Totem-pole gate drive output for power MOSFET. Chip DC power supply pin. Input from auxiliary winding for demagnetization timing. Also this pin is used for output over voltage protection (Load OVP). Brownout and Line OVP detection pin. Connect a resistor divider from line voltage to this pin to detect line voltage. If this pin drops below 0.5V and lasts for 50ms, brownout protection will be triggered and PWM output will be disabled. This pin is also used as line OVP sense input. Confidential -3- Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller BLOCK DIAGRAM VCC Trimmed Voltage/Current Reference 6 UVLO Internal reference Soft Driver GATE 5 POR Timer, Logic, & Fault Management Regulator S Q R Qb On chip Thermal shutdown Internal supply Mode selection FB 2 Valley detector OLP DEM 7 Load OVP BO Latch Soft Start Brownout & Line OVP LEB CS 3 1 SS 4 GND 8 BO RECOMMENDED OPERATING CONDITION Symbol VCC TA Parameter VCC Supply Voltage Operating Ambient Temperature ©On-Bright Electronics Confidential -4- Min 11 -20 Max 28 85 Unit V o C Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller ELECTRICAL CHARACTERISTICS O (TA = 25 C, VCC=18V, if not otherwise noted) Symbol Parameter Test Conditions Supply Voltage (VCC) Section VCC =UVLO(OFF)-1.5V, Istartup VCC Start up Current Measure current into VCC Operation Current I_VCC_quiet FB=3V without switching Operation current with I_VCC_operation FB=3V, 1nF load at GATE switching VCC Under Voltage UVLO(ON) Lockout Enter VCC Under Voltage UVLO(OFF) Lockout Exit (Startup) VCC Over Voltage OVP(ON) Protection Enter VCC Zener Clamp VCC_Clamp I(VCC ) = 5 mA Voltage Feedback Input Section(FB Pin) AVCS PWM Input Gain ΔVFB /ΔVcs VFB_Open FB Open Voltage FB pin short circuit Short FB pin to GND, IFB_Short current measure current Enter PFM mode VTH_PFM_enter threshold Exit PFM mode VTH_PFM_exit threshold Enter Burst Mode VTH_BM_enter threshold Exit Burst Mode VTH_BM_exit threshold Power Limiting FB VTH_PL Threshold Voltage Power limiting TD_PL Debounce Time ZFB_IN Input Impedance Current Sense Input(CS Pin) Section CS Input Leading Edge T_blanking Blanking Time Internal current limiting VTH_OC threshold Over Current Detection TD_OC CL=1nf at GATE, and Control Delay Demagnetization Detection Section Demagnetization VTH_DEM comparator threshold voltage Hysteresis for DEM VTH_DEM_hyst comparator VDEM_clamp(neg) Negative clamp voltage VDEM_clamp(pos) Positive clamp voltage Suppression of the transformer ringing at Tsupp start of secondary stroke ©On-Bright Electronics Confidential -5- Min Typ Max Unit 5 15 uA 2.0 3.5 mA 3.0 5.0 mA 7.8 8.8 9.8 V 14.8 15.8 16.8 V 0.57 33 V 34 V 4.75 5.3 V/V V 1.5 mA 1.4 V 1.5 V 0.5 V 0.7 V 4.4 V 80 mSec 4 Kohm 350 nSec 0.60 0.63 V 100 nSec 75 mV 20 mV -0.5 5.8 V V 2 uSec Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller TOUT TDEM_delay VTH_OVP T_OVP_delay Timeout after last demag transistion Demag propagation delay Output OVP trigger point Output OVP deglitch time constant 3.55 uSec 250 nSec 3.75 3.95 Confidential -6- 8 10 V Switching Cycle 7 Soft Start Section Iss Soft start charge current Soft start termination VTH_ss_exit threshold Maximum sink current ISS_clamp_sink capability when SS is clamped SS pin high clamp VSS_clamp voltage Timer Section Burst mode switching F_burst frequency Frequency high clamp F_QR_clamp_h in QR mode Frequency low clamp in F_QR_clamp_l QR mode Ton_max Maximum on time Toff_max Maximum off time Thermal Protection Thermal shutdown T_shutdown temperature Latch Protection External latch trigger SS pin pull up current V_latch_trigger threshold voltage at SS should be larger than pin 200uA VCC latch release V_latch_release voltage VCC current when latch Ivdd(latch) VCC=V_latch_release+1V off Brownout Protection and Line OVP Protection Brownout comparator Vth_BO threshold Line OVP comparator Vth_line_OVP threshold Brownout debounce TD_BO time BO output current for IBO_hys BO hysteresis programming Gate Drive Output VOL Output Low Level Io = 100 mA (sink) Io = 100 mA (source) VOH Output High Level VCC=20V Output Clamp Voltage VG_Clamp VCC=20V Level T_r Output Rising Time CL = 1nf T_f Output Falling Time CL = 1nf ©On-Bright Electronics 5 12 uA 2.2 V 120 uA 5.8 V 22 KHz 115 130 145 KHz 17 22 27 KHz 20 40 30 50 40 60 uSec uSec 155 ℃ 3.8 V 6.3 V 45 uA 0.5 V 2 V 50 mSec 1 uA 1 7.5 V V 16.5 V 50 20 nSec nSec Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller CHARACTERIZATION PLOTS Istartup(uA) vs Temperature(℃) Ivdd(mA) vs Vdd(V) 4 3 2 1 0 Istarup(uA) Ivdd(mA) 6.0 4.0 2.0 0 10 20 30 0.0 Vdd(V) 20 50 80 Temperature(℃) 110 UVLO(OFF)(V) 16.50 9.50 9.00 8.50 16.00 15.50 15.00 8.00 14.50 -40 -10 20 50 80 Temperature(℃) -40 110 -10 20 50 80 110 Temperature(℃) F_QRmax vs Temperature(℃) Vth_OVP (V) vs Temperature(℃) 3.90 Vth_OVP 135.00 F_Qrmax -10 UVLO(OFF)(V) vs Temperature(℃) UVLO(ON((V) vs Temperature(℃) 10.00 UVLO(ON)(V) -40 130.00 3.80 125.00 3.70 120.00 3.60 115.00 -40 -10 20 50 80 Temperature(℃) -40 110 -10 20 50 80 Temperature(℃) 110 Ics vs V_bo ICS: Internal source current to CS pin for OPP compensation. 100 Ics(uA) 80 60 40 20 0 0 1 2 3 4 V_bo(V) ©On-Bright Electronics Confidential -7- Datasheet OB_DOC_DS_2202A6 OB2202 Quasi-Resonant Flyback PWM Controller OPERATION DESCRIPTION Quasi-Resonant (QR) converter typically features lower EMI and higher power conversion efficiency compared to conventional hard-switched converter with a fixed switching frequency. OB2202 is a highly integrated QR controller optimized for offline flyback converter applications. The built-in advanced energy saving with high level protection features provide cost effective solutions for energy efficient power supplies. pin. The controller monitors the voltage level at FB and control the switching frequency. However, the valley switching characteristic is still preserved in PFM mode. That is, when loading decreases, the system automatically skip more and more valleys and the switching frequency is thus reduced. In such way, a smooth frequency foldback is realized and high power conversion efficiency is achieved.  Startup Current and Start up Control Startup current of OB2202 is designed to be very low so that VCC could be charged up above UVLO(OFF) threshold level and device starts up quickly. A large value startup resistor can therefore be used to minimize the power loss yet reliable startup in application. For a typical AC/DC adaptor with universal input range design, a 2 MΩ, 1/8 W startup resistor could be used together with a VCC capacitor to provide a fast startup and yet low power dissipation design solution. ■ At zero load or very light load conditions (VFBVth2, Figure 1), the system operates in QR mode. The frequency varies depending on the line voltage and the load conditions. Therefore, the system may actually work in DCM when 130KHz frequency clamping is reached. System design should be optimized such that the operation frequency is within the range specified at full loading conditions and in universal AC line input range. 0 Vth2 FB Burst mode Figure 1  Demagnetization Detection The transformer core demagnetization is detected by monitoring the voltage activity on the auxiliary windings through DEM pin. This voltage features a flyback polarity. A new cycle starts when the power switch is activated. After the on time (determined by the CS voltage and FB), the switch is off and the flyback stroke starts. After the flyback stroke, the drain voltage shows an oscillation with a frequency of approximately ■ At light load condition (Vth1