OB2358LAP

OB2358L Current Mode PWM Power Switch Frequency Shuffling Product Specification GENERAL DESCRIPTION FEATURES OB2358L combines a dedicated current mode PWM controller with a high voltage power MOSFET. It is optimized for high performance, low standby power, and cost effective off-line flyback converter applications in sub 27W range. OB2358L offers complete protection coverage with automatic self-recovery feature including Cycle-by-Cycle current limiting (OCP), over load protection (OLP), over temperature protection (OTP), over voltage protection and VDD under voltage lockout (UVLO). Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique together with soft switching control at the totem pole gate drive output. The tone energy at below 20KHZ is minimized in the design and audio noise is eliminated during operation. OB2358L is offered in DIP8 package. ■ 恒 通 志 o lt ia en t APPLICATIONS Power on Soft Start Reducing MOSFET Vds Stress ■ Frequency shuffling for EMI ■ Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design ■ Audio Noise Free Operation ■ Fixed 50KHZ Switching Frequency ■ Internal Synchronized Slope Compensation ■ Low VDD Startup Current and Low Operating Current ■ Leading Edge Blanking on Current Sense Input ■ Good Protection Coverage With Auto SelfRecovery o VDD Under Voltage Lockout with Hysteresis (UVLO) o Over Temperature Protection (OTP) o On-Bright Proprietary Line Input Compensated Cycle-by-Cycle Over-current Threshold Setting For Constant Output Power Limiting Over Universal Input Voltage Range. o Overload Protection (OLP). o Over voltage Protection(OVP) on f id Offline AC/DC flyback converter for ■ AC/DC adapter ■ PDA power supplies ■ Digital Cameras and Camcorder Adapter ■ VCR, SVR, STB, DVD&DVCD Player SMPS ■ Set-Top Box Power ■ Auxiliary Power Supply for PC and Server ■ Open-frame SMPS O nB rig ht C TYPICAL APPLICATION Output Power Table Product 230VAC±15% Open Frame1 27W 85-265VAC Open Frame1 16W OB2358L Notes: 1. Maximum practical continuous power in an open frame design with sufficient drain pattern as a heat sink, at 50℃ ambient. Higher output power is possible with extra added heat sink or air circulation to reduce thermal resistance. ©On-Bright Electronics Confidential -1- Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch GENERAL INFORMATION Frequency Shuffling Package Dissipation Rating Package RθJA (℃/W) DIP8 75 Note: Drain Pin Connected to 100mm2 PCB copper clad. 恒 通 Pin Configuration The OB2358L is offered in DIP8 package as shown below. ia lt o 志 Absolute Maximum Ratings Parameter Value Drain Voltage (off state) -0.3V to BVdss VDD Voltage -0.3V to 30 V VDD-G Input Voltage -0.3V to 30 V FB Input Voltage -0.3 to 7V Sense Input Voltage -0.3 to 7V Maximum Operating Junction 150℃ Temperature TJ Min/Max Storage -55 to 150℃ Temperature Tstg Lead Temperature 260℃ (Soldering, 10secs) Note: Stresses beyond those listed under “absolute en t ht C on f id Ordering Information Part Number Description OB2358LAP DIP8, Pb-free 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. O nB rig Marking Information ©On-Bright Electronics Confidential -2- Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Frequency Shuffling TERMINAL ASSIGNMENTS I/O P FB I VDD-G SENSE VDD P I P Drain O Description Ground Feedback input pin. The PWM duty cycle is determined by voltage level into this pin and the current-sense signal at Pin 4. Internal Gate Driver Power Supply Current sense input IC DC power supply Input HV MOSFET Drain Pin. The Drain pin is connected to the primary lead of the transformer 志 恒 通 Pin Name GND BLOCK DIAGRAM lt o VDD_G 1 Current Reference OTP Soft Driver Power MOSFET ia Internal supply R Q S 5V id on f OVP POR OCP Burst mode SENSE 4 Slope compensation CPL LEB Vth 5.7V PWM Comparator 50ms R OLP FB 3 R 7/8 GND O nB rig ht Burst mode Soft Start Extended OSC C UVLO en t VDD 2 Drain 5/6 ©On-Bright Electronics Confidential -3- Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Frequency Shuffling ELECTRICAL CHARACTERISTICS Typ Max Unit 5 20 uA 1.6 V 25.0 V 4.6 5.2 V 22.0 12.5 ia en t id on f C Confidential -4- V 13.5 ht rig O nB ©On-Bright Electronics 7.8 志 11.5 6.8 mA o 5.8 恒 通 Min 23.5 lt (TA = 25℃, VDD=16V, unless otherwise noted) Symbol Parameter Test Conditions Supply Voltage (VDD) VDD Start up VDD=11V,Measure Istartup Current Leakage current into VDD Operation I_VDD_Operation VFB=3V Current VDD Under UVLO(ON) Voltage Lockout Enter VDD Under UVLO(OFF) Voltage Lockout Exit (Recovery) CS=0V,FB=3V Over voltage OVP(ON) Ramp up VDD until gate protection voltage clock is off Feedback Input Section(FB Pin) VFB Open Loop VFB_Open Voltage FB pin short Short FB pin to GND and IFB_Short circuit current measure current Zero Duty Cycle VTH_0D FB Threshold Voltage Power Limiting VTH_PL FB Threshold Voltage Power limiting TD_PL Debounce Time ZFB_IN Input Impedance Current Sense Input(Sense Pin) Soft start time Leading edge T_blanking blanking time ZSENSE_IN Input Impedance Over Current From Over Current Occurs TD_OC Detection and till the Gatedrive output Control Delay start to turn off Internal Current Limiting FB=3.3V VTH_OC Threshold Voltage Oscillator Normal FOSC Oscillation Frequency Frequency △f_Temp Temperature Stability Frequency △f_VDD Voltage Stability Maximum duty FB=3.3V, CS =0V D_max cycle 4.9 1.15 mA 0.8 V 3.7 V 50 mSec 4 Kohm 4 ms 270 ns 40 Kohm 80 nSec 0.72 0.77 0.82 V 45 50 55 KHZ 5 % % 5 56 66 76 % Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Burst Mode Base Frequency F_Burst Frequency Shuffling 22 KHZ Mosfet Section MOSFET DrainSource BVdss Breakdown Voltage Rdson Static, Id=1.0A Frequency Shuffling Frequency ∆f_OSC Modulation range /Base frequency Over temperature protection Over temperature protection trip point V 4.4 5.5 Ώ 4 % 志 -4 恒 通 600 ℃ O nB rig ht C on f id en t ia lt o 150 ©On-Bright Electronics Confidential -5- Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Frequency Shuffling CHARACTERIZATION PLOTS (The characteristic graphs are normalized at Ta=25℃) UVLO(OFF)(V) vs Temperature(℃ ) 6.86 12.65 6.85 6.84 6.83 0 40 80 12.45 12.35 12.25 -40 120 0 Temperature(℃ ) 40 80 120 Temperature(℃ ) o 5.0 en t id Vth_OC(V) 0.0 10.0 15.0 VDD Voltage(V) 20.0 25.0 Fosc(KHz) vs Temperature(℃ ) on f 30 1.0 0.0 Vth_OC(V)vs duty(%) 15 2.0 ia 0.0 0 3.0 lt VDD Current(mA) 1.0 45 Fosc(KHz) Istartup(uA) 2.0 1.10 1.00 0.90 0.80 0.70 120 VDD vs Operation Current 3.0 0 80 Temperature(℃ ) Istartup(uA) vs Temperature(℃ ) -40 40 志 -40 12.55 恒 通 6.87 UVLO(OFF)(V) UVLO(ON)(V) UVLO(ON)(V) vs Temperature(℃) 60 C Duty(%) 60.0 40.0 20.0 0.0 -40 0 40 80 120 Temperature(℃ ) 8 rig Rds(on) 10 ht Rds(on) VS Temperature(℃ ) 6 nB 4 50 75 100 125 150 Temperature(℃ ) O 25 ©On-Bright Electronics Confidential -6- Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Frequency Shuffling OPERATION DESCRIPTION The OB2358L is a low power off-line SMPS Switcher optimized for off-line flyback converter applications in sub 27W power range. The ‘Extended burst mode’ control greatly reduces the standby power consumption and helps the design easily to meet the international power conservation requirements. 恒 通 The switching frequency is internally adjusted at no load or light load condition. The switch frequency reduces at light/no load condition to improve the conversion efficiency. At light load or no load condition, the FB input drops below burst mode threshold level and device enters Burst Mode control. The Gate drive output switches only when VDD voltage drops below a preset level and FB input is active to output an on state. Otherwise the gate drive remains at off state to minimize the switching loss and reduces the standby power consumption to the greatest extend. The switching frequency control also eliminates the audio noise at any loading conditions. o 志 • Startup Current and Start up Control Startup current of OB2358L is designed to be very low so that VDD could be charged up above UVLO threshold level and device starts up quickly. A large value startup resistor can therefore be used to minimize the power loss yet achieve a reliable startup in application. For AC/DC adapter with universal input range design, a 2 MΩ, 1/8 W startup resistor could be used together with a VDD capacitor to provide a fast startup and yet low power dissipation design solution. ia lt • Oscillator Operation The switching frequency of OB2358L is internally fixed at 50KHZ. No external frequency setting components are required for PCB design simplification. en t • Operating Current The Operating current of OB2358L is low at 2mA. Good efficiency is achieved with OB2358L low operating current together with the ‘Extended burst mode’ control features. id • Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in OB2358L current mode PWM control. The switch current is detected by a sense resistor into the sense pin. An internal leading edge blanking circuit chops off the sensed voltage spike at initial internal power MOSFET on state due to snubber diode reverse recovery and surge gate current of internal power MOSFET so that the external RC filtering on sense input is no longer needed. The current limiting comparator is disabled and cannot turn off the internal power MOSFET during the blanking period. The PWM duty cycle is determined by the current sense input voltage and the FB input voltage. ht C on f • Soft Start OB2358L features an internal 4ms soft start to soften the electrical stress occurring in the power supply during startup. It is activated during the power on sequence. As soon as VDD reaches UVLO(OFF), the peak current is gradually increased from nearly zero to the maximum level of 0.77V. Every restart up is followed by a soft start. • Frequency shuffling for EMI improvement The frequency Shuffling (switching frequency modulation) is implemented in OB2358L. The oscillation frequency is modulated so that the tone energy is spread out. The spread spectrum minimizes the conduction band EMI and therefore eases the system design. O nB rig • Internal Synchronized Slope Compensation Built-in slope compensation circuit adds voltage ramp onto the current sense input voltage for PWM generation. This greatly improves the close loop stability at CCM and prevents the subharmonic oscillation and thus reduces the output ripple voltage. • Extended Burst Mode Operation At light load or zero load condition, most of the power dissipation in a switching mode power supply is from switching loss on the MOSFET, the core loss of the transformer and the loss on the snubber circuit. The magnitude of power loss is in proportion to the switching frequency. Lower switching frequency leads to the reduction on the power loss and thus conserves the energy. ©On-Bright Electronics • Drive The internal power MOSFET in OB2358L is driven by a dedicated gate driver for power switch control. Too weak the gate drive strength results in higher conduction and switch loss of MOSFET while too strong gate drive results the compromise of EMI. A good tradeoff is achieved through the built-in totem pole gate design with right output strength and dead time control. The low idle loss and good Confidential 7 Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch EMI system design is easier to achieve with this dedicated control scheme. In addition to the gate drive control scheme mentioned, the gate drive strength can also be adjusted externally by a resistor connected between VDD and VDDG, the falling edge of the Drain output can be well controlled. It provides great flexibility for system EMI design. Frequency Shuffling 恒 通 output power limit over the universal input voltage range. At overload condition when FB input voltage exceeds power limit threshold value for more than TD_PL, control circuit reacts to shut down the switcher. Switcher restarts when VDD voltage drops below UVLO limit. Similarly, control circuit shutdowns the power MOSFET when an Over Temperature condition is detected. VDD is supplied by transformer auxiliary winding output. When VDD voltage exceeds the internal OVP threshold voltage (23.5V) due to abnormal conditions, The power MOSFET is shut down until VDD drops below 6.8V (UVLO limit) , and device enters power on restart-up sequence thereafter. O nB rig ht C on f id en t ia lt o 志 • Protection Controls Good power supply system reliability is achieved with its rich protection features including Cycle-byCycle current limiting (OCP), Over Load Protection (OLP), over voltage protection and Under Voltage Lockout on VDD (UVLO). With On-Bright Proprietary technology, the OCP is line voltage compensated to achieve constant ©On-Bright Electronics Confidential -8- Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Frequency Shuffling PACKAGE MECHANICAL DATA C on f id en t ia lt o 志 恒 通 8-Pin Plastic DIP Dimensions In Millimeters Min Max O nB rig A A1 A2 B B1 C D E E1 e L E2 3.710 0.381 2.921 0.350 5.334 ht Symbol ©On-Bright Electronics 4.953 0.650 Dimensions In Inches Min Max 0.146 0.015 0.115 0.014 1.524 (BSC) 0.210 0.195 0.026 0.06 (BSC) 0.200 9.000 6.096 7.320 0.360 10.160 7.112 8.255 2.540 (BSC) 2.921 3.810 7.620 10.920 Confidential -9- 0.008 0.354 0.240 0.288 0.014 0.400 0.280 0.325 0.1 (BSC) 0.115 0.300 0.150 0.430 Datasheet OB_DOC_DS_2358LA1 OB2358L Current Mode PWM Power Switch Frequency Shuffling IMPORTANT NOTICE 恒 通 RIGHT TO MAKE CHANGES On-Bright Electronics Corp. reserves the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. lt o 志 WARRANTY INFORMATION On-Bright Electronics Corp. warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with its standard warranty. Testing and other quality control techniques are used to the extent it deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. On-Bright Electronics Corp. assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using On-Bright’s components, data sheet and application notes. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. en t ia LIFE SUPPORT On-Bright Electronics Corp.’s products are not designed to be used as components in devices intended to support or sustain human life. On-bright Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in medical applications. O nB rig ht C on f id MILITARY On-Bright Electronics Corp.’s products are not designed for use in military applications. On-Bright Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in military applications. ©On-Bright Electronics Confidential - 10 - Datasheet OB_DOC_DS_2358LA1