OB3600CPA

OB3600 Dimmable, Non-isolated PWM Controller GENERAL DESCRIPTION FEATURES OB3600 is a dimmable, highly integrated buck regulator with advanced features to provide high efficiency control and high precision constant current output for LED lighting applications. 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. OB3600 offers a dimmable function, the LED current can be controlled by setting the duty cycle of PWM waveform into the DC pin. OB3600 offers comprehensive protection coverage with auto-recovery features including Cycle-by-Cycle current limiting, VDD OVP and UVLO. Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique. OB3600 is offered in SOP8 package.  High Precise Constant Current Regulation at Universal AC input  Dimmable LED Current Control  Quasi-Resonant operation  Adjustable Constant Current, Constant Voltage  Built-in Primary winding inductance compensation  LED short circuit protection  Built-in Leading Edge Blanking (LEB)  Cycle-by-Cycle Current Limiting  VDD Under Voltage Lockout with Hysteresis (UVLO)  Latched over temperature protection (OTP)  VDD OVP APPLICATIONS  Dimmable LED lighting Fig.1. Typical CC/CV Curve TYPICAL APPLICATION ©On-Bright Electronics Confidential -1- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller GENERAL INFORMATION Absolute Maximum Ratings Parameter Gate Voltage Pin Configuration SOP8. FB 1 8 DC NC 2 7 VS CS 3 6 GND VDD 4 5 GATE VDD Voltage CS, FB, VS and DC Input Voltage Min/Max Operating Junction Temperature TJ Operating Ambient Temperature TA Min/Max Storage Temperature Tstg Lead Temperature (Soldering, 10secs) to -0.3 to 7V -40 to 155 ℃ -40 to 85 ℃ -55 to 155 ℃ 260 ℃ 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. Ordering Information Part Number Description OB3600CP SOP8, Pb-free in Tube OB3600CPA SOP8, Pb-free in T&R Package Dissipation Rating Package RθJA (℃/W) SOP8 150 ©On-Bright Electronics Value -0.3 to 25V -0.3 VDD_OVP Recommended Operating Condition Symbol Parameter Range VDD VDD Supply Voltage 12 to 25 V Confidential -2- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller Marking Information TERMINAL ASSIGNMENTS Pin Num Pin Name I/O Description 1 FB I/O Connected to resistor divider from primary winding or auxiliary winding to reflect output voltage 2 NC 3 CS I/O Current Sense Input 4 VDD P Power Supply 5 GATE O Gate Driver Output 6 GND P Ground 7 VS I/O Dimming ON voltage reference select 8 DC I/O Dimming Control Input ©On-Bright Electronics No Connection Confidential 3 Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller BLOCK DIAGRAM UVLO ©On-Bright Electronics Confidential -4- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller ELECTRICAL CHARACTERISTICS (TA = 25℃, VDD=16V, if not otherwise noted) Symbol Parameter Supply Voltage (VDD) section I startup Startup Current I DD op Test Conditions VDD=UVLO_OFF-1V Operation supply current FB=1V, CS=0V, VDD= 20V VDD falling 7.3 VDD rising 15.5 26 Operation Current UVLO(ON) VDD Under Voltage Lockout Enter UVLO(OFF) VDD Under Voltage Lockout Exit VDD_OVP VDD over voltage protection Current Sense Input section TLEB LEB time Vth_oc Over current threshold Td_oc OCP Propagation delay Frequency section Freq_MaxNote IC Maximum frequency Toff_min Minimum Toff F_min Minimum frequency △f/Freq Gain Vth_OVP 20 uA 0.45 1 mA 8.3 16.5 27 9.3 V 17.5 V 28.5 V 508 144 Frequency shuffling range Reference voltage 2 for EA DC gain of EA Load OVP threshold voltage Voltage reference select resistor @ Vref2=3V Gate Driver section VOL Output low level @ VDD=14V, Io=5mA Output high level @ VDD=14V, VOH Io=20mA V_clamping Output clamp voltage T_r Output rising time 1V~ 9V@ CL=500pF T_f Output falling time 9V~1V@ CL=500pF On chip over temperature section Over temperature protection trigger T_otp point Dimming control section Threshold voltage for rising edge VH_DC detection for DC pin  Threshold voltage for falling edge VL_DC detection for DC pin  Note: ns mV ns 2.0 114 KHz us Hz ±3.5 % 0.85 0.9 Vs should be connected 1.62 1.7 to GND Vs should be floated 2.28 2.4 Vs should connect a 2.85 3 resistor to GND 40 Vs should be connected 1.9 to GND Vs should be floated 2.7 Vs should connect a 3.3 resistor to GND 0.95 V 1.78 V 2.52 V 3.15 V V V V 270 R_VS 1. Max Unit 4 500 492 500 100 Error Amplifier section Vref1_EA Reference voltage 1 for EA Vref2_EA Min Typ. KΩ 1 6 V V 10 95 50 V ns ns 155 ℃ 0.85 1 1.15 V 2.55 3 3.45 V Freq_Max indicates IC internal maximum clock frequency. In system application, the maximum operation frequency of 144 KHz nominal occurs at maximum output power or the transition point from CV to CC. ©On-Bright Electronics Confidential -5- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller CHARACTERIZATION PLOTS Istartup(uA) vs Tem perature Vdd(V) vs Ivdd(uA) 7 Istartup(uA) 1000 Ivdd(uA) 800 600 400 200 5.8 4.6 3.4 2.2 1 0 7 9 11 13 15 17 -40 19 -10 UVLO(ON)(V) vs Tem perature 110 140 UVLO(OFF)(V) 18 8.8 8.6 8.4 8.2 8 17.6 17.2 16.8 16.4 16 -40 -10 20 50 80 110 140 -40 -10 Temperature(℃) 906.0 1.706 Vref(1.7V) 1.710 902.0 898.0 1.694 1.690 50 80 110 140 1.698 890.0 20 80 1.702 894.0 -10 50 Vref2(1.7V) vs Tem perature 910.0 -40 20 Temperature(℃) Vref1(900m V) vs Tem perature Vref(900mV) 80 UVLO(OFF)(V) vs Tem perature 9 110 140 -40 -10 Temperature(℃) 20 50 80 110 140 Temperature(℃) Vref2(2.4V) vs Tem perature Vref2(3V) vs Tem perature 3.010 Vref(3V) 2.410 Vref(2.4V) 50 Temperature(℃) VDD(V) UVLO(ON)(V) 20 2.406 2.402 2.398 3.004 2.998 2.992 2.394 2.986 2.390 2.980 -40 -10 20 50 80 110 140 -40 Temperature(℃) ©On-Bright Electronics -10 20 50 80 110 140 Temperature(℃) Confidential -6- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller Vocp(V) vs Tem perature 1 Vocp(V) 0.8 0.6 0.4 0.2 0 -40 -10 20 50 80 110 140 Temperature(℃) ©On-Bright Electronics Confidential -7- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller OPERATION DESCRIPTION OB3600 is a dimmable, non-isolated LED lighting controller which can achieve accurate current for LED lighting applications. Proprietary Constant Voltage (CV) and Constant Current (CC) control is integrated. working frequency and the highest input voltage determines the highest working frequency. The minimum and maximum off-time are set in OB3600. Therefore, the value of inductor should be carefully designed to achieve good LED output current, according to equation 4. Startup Current and Start up Control Startup current of OB3600 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. Adjustable CC point and Output Power In OB3600, 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.1. Operating Current The Operating current of OB3600 is as low as 0.45mA (Typ.). Typical good efficiency is achieved with the low operating current. Vo Large Rs Principle of CC Operation For buck type operating in transition mode, the peak voltage of CS is detected cycle-by-cycle, and compared with internal reference voltage, Vth_ocp (typical value 500mV).When the voltage at CS pin is up to the threshold voltage, the power switch will be turned off. (1) V Ipk  Small Rs Io th _ ocp RCS Figure.1 Adjustable output power by changing Rs Where, Rcs indicates the resistor at CS pin for primary side current sensing. Refer to the equation 1, LED output current is (2) I pk Vth _ ocp ILED   2 2  RCS OB3600 works under transition mode and the on-time for power switch is (3) L  Ipk ton  Vin  VLED Where L is the inductor of transformer at primary-side winding, Vin is line voltage after rectifying and VLED is the voltage at LED. When power switch turns off, the current flowing in the inductor will reduce to zero and the power switch will turn on after then. The off-time for power switch is (4) L  Ipk toff  VLED The inductor could also be calculated by (5) VLED  VinVLED Operation switching frequency The switching frequency of OB3600 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 144KHz internally. For buck operating in QR, The maximum output power is given by 1 2 PO max  LP FSW I pk 2 Where Lp indicate the inductance of winding and Ipk is the peak current of 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. 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 0.9 or 2.4V (VS pin floating), with dummy load over Pmin. L f  Ipk Vin Where, f is the working frequency. The working frequency changes with input voltage. The lowest input voltage determines the lowest ©On-Bright Electronics (4) Confidential -8- Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller R2 Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in OB3600. 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. + GND Vout R1 FB Protection Control Good power supply system reliability is achieved with its rich protection features including Cycle-by-Cycle current limiting (OCP), VDD OVP, on-chip OTP, and Under Voltage Lockout on VDD (UVLO). Figure.2 FB Section Circuit V OUT  Pmin R1  R 2  V ref R1 1  Vth _ oc    2  R CS _ CV 2   F min L priamry  Latched Over Temperature Protection Over temperature protection is offered in OB3600. When temperature of the device rises over 155℃ (typical), the switching frequency will decrease to half. And the state will be kept until the device restarts. Vth_oc — Over current protection threshold voltage Fmin — Minimum switching frequency, which is 103Hz (typ.) UVLO VDD is supplied by transformer winding output. The output of OB3600 is shut down when VDD drops below UVLO (ON) limit and the power converter enters power on start-up sequence thereafter. If the dummy load is less than Pmin, the output voltage rises up. If the voltage at FB pin exceeds a threshold of approximately 2.7V (VS pin floating), the over-voltage protection function is activated and the switching is turned off immediately. V OVP Dimming (Error Amplifier Reference Voltage Switch) Control Dimming (Error Amplifier Reference Voltage switch) control is offered in OB3600. Default the DC pin is pulled up with 1mA current source. The error amplifier reference voltage is 0.9V. If the DC pin is pulled down, the error amplifier reference voltage is switched to 2.4V (VS pin floating). Dimming ON voltage reference offering pin programmable selection of three popular voltage 1.7V, 2.4V, 3V. The connecting of the programming pin as shown in table: R1  R 2   V vth _ OVP R1 CC Line Regulation Adjust the R2 for better CC line regulation, while driving different type MOSFET. The larger MOSFET, the smaller R2 needed. If the resistance is too large, it causes the interference, too small resistance results the efficiency decreased at HV AC line. Frequency shuffling for EMI improvement The frequency shuffling (switching frequency modulation) is implemented in OB3600. 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. ©On-Bright Electronics VS pin connecting Connecting to GND Floating Connecting to GND with 270K resistor Confidential -9- Vref2 1.7V 2.4V 3V Vth_OVP 1.9V 2.7V 3.3V Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller PACKAGE MECHANICAL DATA Symbol A A1 A2 b c D E E1 e L θ ©On-Bright Electronics Dimensions In Millimeters Min Max 1.350 1.750 0.050 0.250 1.250 1.650 0.310 0.510 0.170 0.250 4.700 5.150 3.800 4.000 5.800 6.200 1.270 (BSC) 0.400 1.270 0º 8º Confidential - 10 - Dimensions In Inches Min Max 0.053 0.069 0.002 0.010 0.049 0.065 0.012 0.020 0.006 0.010 0.185 0.203 0.150 0.157 0.228 0.244 0.05 (BSC) 0.016 0.050 0º 8º Preliminary Datasheet OB_DOC_DS_360001 OB3600 Dimmable, Non-isolated PWM Controller IMPORTANT NOTICE 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. 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. 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. 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 - 11 - Preliminary Datasheet OB_DOC_DS_360001