controller,designed for non-isolated buck LED driver. It input. the system cost. C S C S G N D V C C SO URCE

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1 Constant Current Controller for Non-isolated Buck Driver Features nductor Current Critical Mode, No Need to Compensate the nductance Variation 550V MOSFET integrated Source Driver Structure, Not Need the Auxiliary Winding for VCC ±3% Current Accuracy Up to 93% System Efficiency Open/Short Circuit Protection Current Sense Resistor Short Circuit Protection Over Temperature Protection Programmable open protection Frequency shuffling Applications Bulb Candle light Spot light Decorative lighting T5/T8 Lamp Ceiling Lamp Flat Lamp General Description The is a high precision constant current controller,designed for non-isolated buck driver. t can operate under universal AC input or 1V~550V DC input. The integrates 550V power MOSFET, so it can achieve excellent constant current performance with very few external components. The uses high precision current sense circuit and patent method for constant current control, to achieve high precision output current and excellent line regulation. The operates in inductor current critical mode. The current is constant over wide range of inductance variation and the output voltage, so the load regulation is excellent. The uses patent source driver architecture. The operation current is 00uA only, so the auxiliary winding is not needed. t can simplify the system design and reduce the system cost. The offers rich protection functions, including open/short circuit protection, current sense resistor short circuit protection and over temperature protection. Typical Application Circuit A C 1 G N D 8 R O V P 7 3 V C C D R A N 6 4 SO URCE D R A N 5 W/T-DS08-Rev.A/ 0 Nov.013 Copyright@Winsemi MicroelectronicsCo., Ltd., All right reserved. 1113

2 Pin Definition and Device Marking is available in DP-8 package. G N D R O V P V C C So u rc e D8P AXB YM D R A N D R A N D8P: Product code A: Product Code X:nternal Code B:Area Code YM:Year, Month Pin Function Description Pin Name Pin NO. Description GND 1 Ground ROVP Programmable open protection pin,connect a resistor to GND VCC 3 Power supply Source 4 Source driver output, connect to the source of power-mos DRAN 5,6 nternal HV power MOSFET drain CS 7,8 Current sense input, the sense resistor is connected from CS to ground Block Diagram V C C 3 D r a in 5, 6 G N D 1 Soft-Driver U V L O nter s upply Zero-Current Detec t 4 So u r ce L in e c ompens ation m V O C P L o g ic & driv er CS Short Short R O V P L E D O P E N PR O TEC TO N O T P 7, 8 /7

3 Ordering nformation Package Part Number Marking 8-Pin DP-8, Pb-free D8P D8P Recommended Operating Condition symbol symbol parameter value units P output power < 8 W Absolute Maximum Ratings symbol parameter Range Units VDS nternal HV MOSFET drain voltage -0.3~550 V CC_MAX VCC pin maximum sink current.5 ma VROVP ROVP input voltage -0.3~7 V VCS Current sense pin input voltage -0.3~7 V PDMAX Power dissipation 0.9 W TJ Operating junction temperature 150 TSTG Storage temperature range -55~150 Note: Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. Under recommended operating conditions the device operation is assured, but some particular parameter may not be achieved. 3/7

4 Electrical Characteristics (Unless otherwise specified,ta5,vcc16v) Symbol Parameter Conditions Min Typ Max Units Supply Voltage Section Vcc_clamp VCC Clamping Voltage V cc_clamp VCC Clamping Current ma VCC_ST VCtart Up Voltage VCC Rise V Vuvlo_HYS VCC Under Voltage Latch Out Hysteresis VCC Falling V st Start Up Current VCC<VCC_ST-0.5V ua op Operation Current ua Current Sensor Section Vcs_th Current Sensor Voltage Threshold mv TLEB Leading Edge Blanking ns TDELAY Turn Off Delay Time ns nternal Driver Section TOFF_MN Minimum Demagnetization Time us TOFF_MN Maximum Demagnetization Time us TON_MAX Maximum Turn On Time us nternal HV MOSFET RDSON Switch ON Resistance VGS10V, D1.0A ohm VDS_BD Drain to Source voltage D50μA V Over Temperature Section TSD Thermal Shut Down Temperature TSD_HYS Thermal Shut Down Hysteresis /7

5 Function Description is a constant current controller, designed for driving non-isolated buck power supply. integrates 550V power MOSFET, and it uses patent constant current control method and source driver structure, excellent constant current characteristic is achieved with low counts components. Low cost and high efficiency of system is realized. The is the peak current in inductor. Line Compensation The integrates line compensation function. Excellent line regulation is achieved. Source Driver Structure Start up The Vcc will be charged through the startup resistor when the system is powered on. When the voltage on The uses the patent source driver structure. The typical operation current is as low as 00uA, the auxiliary winding is not need. So the system design is simple and the cost is low. Vcc reaches the startup voltage threshold, the controller starts to switching. The Vcc clamped to 18V by internal Zener diode. voltage of is nductance Calculation Constant Setting Current Control and Output Current The is designed to work in inductor current critical mode, the energy will be stored in the inductor when the MOSFET is turned on. The turn on time is The uses patent constant current control method, excellent constant current is achieved with low counts components. The senses the peak given by: t on L V V N current in inductor cycle by cycle. The CS Pin is connected to the input of internal current comparator, and compared with the internal 400mV reference voltage. The external power MOSFET will be turned off when the CS pin voltage reaches the voltage threshold. The comparator has a 350ns LEB timer to avoid mis-trigger. The peak current in the inductor is given by: 400 ( ma ) R CS The L is the inductance. The pk is the peak current in inductor. The VN is the input rectified voltage. The V is the voltage on. When the power MOSFET is turned off, the inductor current will decrease from the peak current to zero. The turn off time is given by: The MOSFET will be turned on again when it detects the The Rcs is the resistance of current sense resistor The current in can be calculated by the following inductor current goes to zero. The inductance can be equation: calculated by the following equation: 5/7 t off L V

6 V L ( V f N V V N The f is the system switching frequency, which is ) n which the Vcs is the OCP threshold (0.4V),the Vovp is the new target output protection voltage. And the value proportional to the input voltage. So the minimum switching frequency is set at lowest input voltage, and maximum switching frequency is set at highest input voltage. of the resistor Rovp is as below: Rovp 15 * Tovp *10 Protection Functions 6 (KΩ) The internally set the minimum off time to 4us and maximum off time to 130us. When the inductance is very small, the toff may goes below the minimum off time and the inductor current becomes discontinuous. So the output current will be smaller than the setting value. f the inductance is too large, the toff may goes beyond the maximum off time and the inductor current becomes continuous. And the output current will be larger than the setting value. So it s very important to select a right inductance. The also internally set the maximum on time to 40us. When the input voltage is very low or output voltage is very high, the ton may goes beyond the maximum on time. The power MOSFET will be turned off even the inductor current still below the setting value. So the output current will be smaller than the setting value. Set open protection The has many protection functions, including open/short circuit protection, current sense resistor short circuit protection and over temperature protection. All of the protection functions are designed to auto-recover. The over temperature protection circuitry in the monitors the die junction temperature after start up. When the temperature rises to 150, the power MOSFET will be shut down immediately and maintains at switch off condition until the temperature on die falls 30 below the thermal protection trigger point. PCB Layout The following guidelines should be followed in PCB layout: Bypass Capacitor The bypass capacitor on VCC pin should be as close as possible to the VCC and GND pins. Ground Path The power ground path for current sense should be short, The open protection voltage can be set by adjusting and the power ground path should be separated from the value of the resistor connecting from ROVP to GND. small signal ground path before the negative node of the Rovp voltage is 0.5V. bus capacitor. n the open condition, the output voltage will raise The Area of Power Loop graduate, and the demagnetize time will shorten as well, The area of main current loop should be as small as the demagnetize time Tovp can be calculator as below: possible to reduce EM radiation. And the controller Tovp L V R V CS (KΩ) CS OVP should be placed away. from the heat generator, such as the power diode. 6/7

7 Package nformation DP-8 Package Outline Dimensions θ θ1 D C1 C C4 C C3 θ3 A 5 A 1 A A 3 A 4 D 1 D A B Winsemi Symbol Dimensions in Millimeters Dimensions in nches Min Max Min Max A B C A A A A4 0.51TYP 0.0TYP A5 0.99TYP 0.04TYP C C 0.50TYP 0.0TYP C C D D D 7.6TYP 0.3TYP W/T-DS08-Rev.A/ 0 Nov.013 Copyright@Winsemi MicroelectronicsCo., Ltd., All right reserved. 1113