EC4318 E-CMOS | Alldatasheet
Document overview
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Technical content
Features
/rhombus6 High Power Factor, ultra- low THD /rhombus6 Valley Switch, High Efficiency, LOW EMI /rhombus6 High- V MOSFET embedded /rhombus6 Thermal Regulation Compensation /rhombus6 ±3% Output Current Accuracy /rhombus6 Universal AC input /rhombus6 Auto Induction Compensate /rhombus6 Auto Output Voltage adaption /rhombus6 Full Protection Features: ( LED O/S CKT; OTP OCP; OVP/UVP) /rhombus6 Auto Recovery to default /rhombus6 Fewest external components required on board
Applications
/rhombus6 LED High Brightness Lighting /rhombus6 Light Bulb, Light Tube Typical Application
Offiline Step- down Buck LED Driver IC with APFC Pin Configuration EC4318 performed in SOP-8 Package shown as below ： Pin Definition Pin Name Pin# Feature Description COMP 1 Loop Compensation Node. This pin connects a capacitor to GND for stabilization of the control loop, achievi ng accurate LED current, high Power Factor and low THD. VCC 2 Power Supply Pin. Connect a bypass capacitor from this pin to GND FB 3 Feedback Voltage Input Pin. This pin detects the inductor demagnetization signal and the output voltage. CS 4 Current Sense Pin. Connect a resistor to GND to sense the inductor current; Source of the internal HV MOSFET Drain 5 Drain of the internal HV MOSFET Drain 6 Drain of the internal HV MODFET GND 7 Ground GND 8 Ground
Ordering Information
Part No. Package type Marking Remark EC4318NNM1R SOP-8L EC4318 LLLLL YYWWT 1. LLLLL ：LOT NO. 2. YYWW ：Date code 3. T： Tracking code EC 4318 NN XX X R : Tape Reel M1 ：SOP-8L
Offiline Step- down Buck LED Driver IC with APFC Block Diagram Absolute Maximun Rating ˄ Note 1 ˅ Symbol Parameter Range VCC Input voltage -0.3~ clamp Voltage V VD Internal HV MOSFET Drain to Source -0.3~500 V VCS Current sense pin input voltage -0.3~7 V VFB Feed back pin input voltage -0.3~7 V VCOMP Compensation pin voltage -0.3~7 V PDMAX Power dissipation （Note2 ） 0.45 W TJ Maximum junction temperature 160 ℃ TSTG Storage temperature -55~150 ℃ Note 1: 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. The electrical characteristics table defines the operation range of the device, the electrical characteristics is assured on DC and AC voltage by test program. For the parameters without minimum and maximum value in the EC table, the typical value defines the operation range, the accuracy is not guaranteed by spec. Note 2: The maximum power dissipation decrease if temperature rise, it is decided by TJMAX, θJA, and environment temperature (TA). The maximum power dissipation is the lower one between PDMAX = (TJMAX - TA)/ θJA and the number listed in the maximum table. Recommended Operating Condition Condition Parameter Unit 85~ 264Vac (full range) ≤12 W Vac input 175~264Vac (single range) ≤18 W TA Operating temperature -20~85 ℃
Offiline Step- down Buck LED Driver IC with APFC Electrical Characteristics (Unless otherwise specified, VCC=8V and TA =25 )℃ Symbol Parameter Condition Min. Typ. Max. Unit Supply Voltage Section VCC_clamp VCC clamp Voltage 7.5 8.0 8.5 V ICC_clamp VCC clamp Current 5 mA VCC_ST Start-up Voltage VCC rising 7.07 7.57 8.07 V Vuvlo_HYS UVLO Hysteresis Voltage VCC falling 1.32 V Ist Start-up Current VCC < VCC_ST - 0.5V 70 100 uA Iop Operating Current 400 600 uA Current Sensing Section Vocp OCP Peak Voltage Limitation 1 V TLEB Leading Edge Blanking Time for Current Sense 350 ns Td Switch off Delay Time 200 ns Compensation Section VREF Internal Reference Voltage 194 200 206 mV VCL COMP Low Clamp Voltage 1.5 V VCH COMP High Clamp Voltage 4.0 V Internal Driving Section TOFF_MIN Minimum Off Time 3 us TON_MAX Maximum On Time 20 us TOFF_Max Maximum Off Time 100 us Feedback Section VFB FB Over Voltage Protection Threshold 1.6 V VZCD FB Falling Edge Threshold Voltage 0.2 V High V MOSFET Section R DSON D-S on resistance VGS =10V/I DS =0.5A 5 Ω VDS D-S breakdown Voltage VGS =0V/I DS =250uA 500 V Over Temp. Protection Sction Tcomp TSD Thermal regulation Temp. OTP Shut Down Temp. 150 160 TSD TSD OTP Shut Down Temp. OTP Shut Down Temp. 160 160 TSD_HYS Shut Down Hysteresis Temp. 30
Offiline Step- down Buck LED Driver IC with APFC Application Info. EC4318 is a high precision Active PFC driver which integrates 500V power MOSFET, specifically designed for non-isolated buck offline constant current LED lighting. Even when switching in critical conduction condition, EC4318 achieves high power factor, high efficiency and ultra- low THD. Start- up With ultra- low start- up power (Typ.@70uA, Max. @ 100uA)ˈ when it is applied at Vac = 85V to start- up ˈ the start- up Resistance can be calculated in below ˖ Chip Power supply and consumption After EC4318 being started-up ˈthe rectifier D6 is crucial to adopt fast recovery Diode. The formula of Current- limi t resistance R4 would be ˖ In which “D” stands for duty Cycle ˈand 400uA is normal operating current of EC4318 ˈ VLED is output loading voltage. Power consumption of this certain Resistor can be calculated at ˖ For instance ˖when Solution requires ˖ Vac in= 180~260V ˈVout= 36~80V ˈIout= 240m Then, in low range of Vac in=180V; Vout =36V => R4 could be generated in the following calculation: In high range of Vac in= 260V ˈVout= 80V ˈthen D=80/260/1.414=0.218 ˈand the power consumption of resistance is ˖ Output Current control The EC4318 utilizes floating ground structure. The inductor current is sensed during the whole switching cycle, hence it achieves high precision output current and perfect line and load regulation. The current in LED can be calculated by equation of: Where 200mV is the internal reference voltage, and Rcs is the value of current- sensing resistor. Feedback Voltage measurement (OVP) Voltage on FB pin determines operating state on board ˈ when it reaches over 1.6V(Typ.) , EC4318 would sense and turn into Over- Voltage Protection mode ˈ and system is thus jump to power- saving “ hiccup mode” ˈOVP voltage is generated by ˖ Please refer to typical application schematic to find R2 & R3, in which R 3=10K, ˄15K Max., and 8.2K Min. ˅ˈ in above formula, the Constant 1.6 can be put 1.3 when designing systems, Set Vovp= 90V, we can come out R 2=552K from above equation, herewith, we adopt 560K resistor instead. As VFB is between 1.3-1.9, when choosing the withstand voltage of C4, It is recommended to set @ 1.9 ˈhence, Vovp =1.9* ˄10+560 ˅/10 =108V ˈ moreover, the Withstand Voltage of C4 must be over Vovp ˈherein We choose C4 @ 200V. After EC4318 falls in “hiccup mode”, the output voltage is automatically sensed constantly in working cycles. When output voltage is beneath Vovp, system would recover to normal function state.
Offiline Step- down Buck LED Driver IC with APFC LED Open/ Short Protection When the LED is open circuit, the output voltage will gradually rise up. The output voltage is sensed by the FB pin when power MOSFET is turned off. When FB voltage reaches the OVP threshold, it will trigger fault logic and the system stops switching. When the LED is shorted circuit, the system will work under 10kHz switching frequency. Meanwhile, the output voltage is low and the V CC pin cannot be charged up by the output voltage, so the V CC pin voltage will gradually decrease and finally reaches the UVLO threshold. Thermal Regulation (Over Temp. Protection) The EC4318 integrates thermal regulation function. When the system is over temperature, the output current is gradually reduced; the output power and thermal dissipation are also reduced. The system temperature is regulated and the system reliability is improved. The thermal regulation temperature is set to 150 internally.℃ Filtering input Capacitor With purposes to gain higher power factor, this Cap. Is suggested to set @ 10-100nF PCB Layouts The following guidelines is recommended in EC4318 PCB layout: Bypass Capacitor: The bypass capacitor on V CC pin should be as close as possible to the V CC and GND pins. Ground Path: The power ground path for current sense resistor should be short and wide, and it should be as close as possible to the IC ground pins, otherwise the LED output current accuracy may b e affected. The IC signal ground for COMP and FB components should be connected to the IC GND pins with short traces, and should be away from the power ground path. The Area of Power Loop The area of main current loop should be as small as possible to reduce EMI radiation. FB Pin The feedback resistor divider should be as close as possible to the FB pin, and the trace must keeps away from dynamic node of the inductor (DRAIN Pin trace), otherwise the FB pin OVP function might have risk to be mis- triggered by noise in system. DRAIN Pin To increase the copper area of DRAIN pin for better thermal dissipation. However, over- enlarged copper pad might also compromise EMI performance. Please leverage.
Offiline Step- down Buck LED Driver IC with APFC