OB3398MP

OB3398 High Precision Off-line Primary-Side PWM Power Switch FEATURES OB3398 is a primary side regulation off-line LED lighting controller which can achieve accurate LED current. It significantly simplifies LED lighting system design by eliminating the secondary side feedback circuitry. Proprietary Constant Voltage (CV) and Constant Current (CC) control is integrated as shown in the figure below. The LED current (CC control) can be adjusted externally by the resistor Rs at CS pin. OB3398 offers comprehensive protection coverage with auto-recovery features including Cycle-by-Cycle current limiting, VDD clamp and UVLO. Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique. OB3398 is offered in SOT23-5 package.  High Precise Constant Current Regulation at Universal AC input  Primary-side Sensing and Regulation Without TL431 and Opto-coupler  Floating PSR control scheme with two transformer windings  Adjustable Constant Current and Output Power Setting  Built-in Primary winding inductance compensation  Built-in Leading Edge Blanking (LEB)  Cycle-by-Cycle Current Limiting  VDD Under Voltage Lockout with Hysteresis (UVLO)  Over temperature protection (OTP)  VDD Clamp lt o 铱 宝 GENERAL DESCRIPTION tia APPLICATIONS co n Fig.1. Typical CC/CV Curve fid en Low Power AC/DC offline SMPS for  LED applications O nB rig ht TYPICAL APPLICATION ©On-Bright Electronics Confidential -1- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller GENERAL INFORMATION Pin Configuration SOT23-5. lt o 铱 宝 Absolute Maximum Ratings Parameter Value Gate Voltage -0.3 to 25V VDD Voltage -0.3 to VDD_clamp CS Input Voltage -0.3 to 7V FB Input Voltage -0.3 to 7V Min/Max Operating Junction -40 to 150 ℃ Temperature TJ Operating Ambient -40 to 85 ℃ Temperature TA Min/Max Storage -55 to 150 ℃ Temperature Tstg Lead Temperature 260 ℃ (Soldering, 10secs) Note: Stresses beyond those 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. fid en Recommended Operating Condition Symbol Parameter Range VDD VDD Supply Voltage 12 to 25 V O nB rig ht co n Package Dissipation Rating Package RθJA (℃/W) SOT23-5 200 tia Ordering Information Part Number Description OB3398MP SOT23-5, Pb-free,T&R ©On-Bright Electronics Confidential -2- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller Marking Information TERMINAL ASSIGNMENTS I/O O I P 4 FB I 5 GND P Description Gate driver output Current sense input. Power Supply Connected to resistor divider from primary winding or auxiliary winding to reflect output voltage. Ground fid en Pin Name GATE CS VDD O nB rig ht co n Pin Num 1 2 3 lt o tia Y:Year Code WW:Week Code(01-52) ZZZ: Lot code s: Internal code 铱 宝 398YWW . ZZZ s ©On-Bright Electronics Confidential 3 Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller fid en tia lt o 铱 宝 BLOCK DIAGRAM O nB rig ht co n EA ©On-Bright Electronics Confidential -4- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller ELECTRICAL CHARACTERISTICS (TA = 25℃, VDD=16V, if not otherwise noted) Symbol Parameter Test Conditions Min Typ. Max Unit Supply Voltage (VDD) Section Startup Current VDD=UVLO_OFF-1V 4 I DD op Operation Current Operation supply current FB=1V, CS=0V, VDD= 20V 0.45 UVLO(ON) VDD Under Voltage Lockout Enter VDD falling 7.3 UVLO(OFF) VDD Under Voltage Lockout Exit VDD rising 15.5 16.5 VDD_clamp IDD=20mA LEB time Vth_oc Over current threshold Td_oc OCP Propagation delay Frequency Section Freq_MaxNote IC Maximum frequency Minimum Toff F_min Minimum frequency ᇞf/Freq Frequency shuffling range Error Amplifier section co n Toff_min 1 铱 fid en TLEB tia Current Sense Input Section 8.3 uA 9.3 mA V 17.5 V 25 V 500 ns lt o Maximum VDD operation voltage 20 宝 I startup 492 500 508 100 mV ns 103 KHz 4.0 us 103 Hz ±7 % 1.14 1.2 1.26 V Vref_EA Reference voltage for EA Gain DC gain of EA 40 Vth_OVP Load OVP threshold voltage 1.4 V ht Gate Driver Section VOH Ouput low level @ VDD=14V, Io=5mA rig VOL level @ VDD=14V, Output clamp voltage nB V_clamping Ouput high Io=20mA 1 6 V V 10 V T_r Output rising time 1V~ 9V@ CL=500pF 95 ns T_f Output falling time 9V~1V@ CL=500pF 50 ns On chip Over temperature Section Over temperature protection trigger point 135 ℃ T_otp_rec Over temperature protection recovery point 120 ℃ O T_otp Note: 1. Freq_Max indicates IC internal maximum clock frequency. In system application, the maximum operation frequency of 103KHz nominal occurs at maximum output power or the transition point from CV to CC. ©On-Bright Electronics Confidential -5- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller CHARACTERIZATION PLOTS Istartup(uA) vs Tem perature Vdd(V) vs Ivdd(uA) 7 600 400 200 4.6 3.4 2.2 1 0 7 9 11 13 15 17 -40 19 -10 80 110 140 UVLO(OFF)(V) vs Tem perature 18 UVLO(OFF)(V) 9 8.8 17.6 17.2 tia 8.6 lt o UVLO(ON)(V) vs Tem perature 8.4 8.2 8 16.8 16.4 16 -40 -10 20 50 80 Temperature(℃) fid en UVLO(ON)(V) 50 Temperature(℃) VDD(V) 110 140 -40 co n Vref(V) vs Tem perature 1.26 1.22 1.14 1.1 -10 20 50 80 20 50 80 110 140 Temperature(℃) Vocp(V) vs Tem perature 0.8 0.6 0.4 0.2 0 110 140 -40 rig -40 ht 1.18 -10 1 Vocp(V) 1.3 Vref(V) 20 铱 Ivdd(uA) 800 5.8 宝 Istartup(uA) 1000 20 50 80 110 140 Temperature(℃) O nB Temperature(℃) -10 ©On-Bright Electronics Confidential -6- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller OPERATION DESCRIPTION Since TDemag is inversely proportional to the inductance, as a result, the product Lp and fsw is constant, thus output current will not change as primary winding inductance changes. Up to ±7% variation of the primary winding inductance can be compensated. The output LED current is  Startup Current and Start up Control Startup current of OB3398 is designed to be very low so that VDD could be charged up above UVLO threshold and starts up quickly. A large value startup resistor can therefore be used to minimize the power loss in application. Where N is the ratio of transformer between primary winding and secondary winding. Vth _ oc 1 N 4 Rs lt o  Adjustable CC point and Output Power In OB3398, the CC point and maximum output power can be externally adjusted by external current sense resistor Rs at CS pin as illustrated in Typical Application Diagram. The output power is adjusted through CC point change. The larger Rs, the smaller CC point is, and the smaller output power becomes, and vice versa as shown in Fig.2. tia  Operating Current The Operating current of OB3398 is as low as 0.45mA(Typ.). Typical good efficiency is achieved with the low operating current together with ‘Multi-mode’ control features. fid en Vo co n  Principle of CC Operation To support OB3398 proprietary CC control, system needs to be designed in DCM mode for flyback system (Refer to Typical Application Diagram on page1). The LED output current ILED is given by: I LED  1 2 LP  FSW  I PK  VO 2 (1) ht  Operation switching frequency The switching frequency of OB3398 is adaptively controlled according to the load conditions and the operation modes. No external frequency setting components are required. The operation switching frequency at maximum output power is set to 103K Hz internally. For flyback operating in DCM, The maximum output power is given by (2) 1 2 PO max  LP FSW I pk 2 (4) Where Lp indicate the inductance of primary winding and Ipk is the peak current of primary winding. The principle of CC operation sets the product Lp and fsw to be a constant, thus the maximum output power and constant current in CC mode will not change as primary winding inductance changes. Up to +/-7% variation of the primary winding inductance can be compensated. O 2TDemag Small Rs Figure.2 Adjustable output power by changing Rs rig nB 1 Large Rs Io Where Lp indicates the inductance of primary winding, Ipk is the peak current of primary winding. Refer to the equation 1, the change of the primary winding inductance results in the change of the constant output current. To compensate the change from variations of primary winding inductance, the switching frequency is locked by an internal loop such that the switching frequency is FSW  (3) 铱 I LED  宝 OB3398 is a cost effective PWM controller optimized for off-line LED lighting applications. Based on floating flyback converter topology working in DCM mode, it operates in primary side sensing and regulation, thus opto-coupler and TL431 are not required. Proprietary built-in CC control can achieve high precision LED current meeting LED lighting application requirements. Figure.1 Primary voltage waveform ©On-Bright Electronics Confidential -7- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller  CC Line Regulation Adjust the R1 for better CC line regulation, while driving different type MOSFET. The larger MOSFET, the smaller R1 needed. R1 allow the change from 330K to 1M ohms to cover all the applications. If the resistance is too large, it causes the interference due to the floating ground, too small resistance results the efficiency decreased at HV AC line.  CV / OVP Mode When LED string is open, an output voltage condition is monitored independently by the voltage at FB pin. During normal operation, the voltage at FB pin is regulated at 1.2V (typ.), with dummy load over Pmin. NP GND NS 宝 R2 Vout  Frequency shuffling for EMI improvement The frequency shuffling (switching frequency modulation) is implemented in OB3398. 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. FB Figure.3 FB Section Circuit N S R1  R 2   V ref NP R2 Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in OB3398. The switch current is detected by a sense resistor into the CS pin. An internal leading edge blanking circuit chops off the sensed voltage spike at initial power MOSFET on state so that the external RC filtering on sense input is no longer needed. The PWM duty cycle is determined by the current sense input voltage and the EA output voltage.  _ CV tia V OUT    F min L priamry   Protection Control Good power supply system reliability is achieved with its rich protection features including Cycle-by-Cycle current limiting (OCP), VDD clamp, on-chip OTP, and Under Voltage Lockout on VDD (UVLO). VDD is supplied by transformer primary winding output. The output of OB3398 is shut down when VDD drops below UVLO (ON) limit and the power converter enters power on start-up sequence thereafter. co n Pmin 2 fid en R1 —Resistor connected between the FB pin and the input capacitor GND, the value suggested is 330Kohms~1Mohms R2 —Resistor connected between the FB pin and the GND pin of IC, the value suggested is 5Kohms~15Kohms 1  Vth _ oc    2  R CS Vth_oc — Over current protection threshold voltage Fmin — Minimum switching frequency, which is 103Hz (typ.) rig ht If the dummy load is less than Pmin, the output voltage rises up. If the voltage at FB pin exceeds a threshold of approximately 1.4V (typical), the over-voltage protection function is activated and the switching is turned off immediately. N S R1  R 2   V vth _ OVP NP R2 O nB V OVP  lt o 铱 R1 ©On-Bright Electronics Confidential -8- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller PACKAGE MECHANICAL DATA co n fid en tia lt o 铱 宝 5-Pin Plastic SOT (SOT23-5) Dimensions In Millimeters Symbol Min Max 1.000 1.450 0.039 0.057 0.000 0.150 0.000 0.006 rig A1 Max ht A Min A2 0.900 1.300 0.035 0.051 b 0.300 0.500 0.012 0.020 c 0.080 0.220 0.003 0.009 D 2.800 3.020 0.110 0.119 E 1.500 1.726 0.059 0.068 E1 2.600 3.000 0.102 0.118 nB O Dimensions In Inches e 0.950 (BSC) 0.037 (BSC) e1 1.800 2.000 0.071 0.079 L 0.300 0.600 0.012 0.024 θ 0º 8º 0º 8º ©On-Bright Electronics Confidential -9- Preliminary Datasheet OB_DOC_DS_339801 OB3398 High Precision Off-line Primary-Side PWM Controller IMPORTANT NOTICE 宝 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 铱 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 application 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. fid en tia 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 co n 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 - Preliminary Datasheet OB_DOC_DS_339801