EC4304 E-CMOS | Alldatasheet
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Technical content
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch GENERAL DESCRIPTION
FEATURES
The EC4304 is a high-efficiency continuous mode inductive step-down converter which drives N-channel MOSFET and it is designed for driving single or multiple series connected LEDs from a voltage source higher than the LED voltage. It operates from input supply between 7V and 40V and provides and externally adjustable output current to 1A which is depending on supply voltage and external components. This EC4304 includes the output switch and high-side output current sensing circuit, which uses an external resistor to set the output current. The ADJ pin will accept either a DC voltage or a PWM waveform. This will provide either a continuous or gated output current depending upon the control frequency. The PWM filter components contains a soft-start rising time setting. The soft-start time can be increased by using an external capacitor from the ADJ pin to ground. Applying a 0.2V or lower to the ADJ pin turns the output off and switches the device into a low current standby state. /circle6 Operates from 7V to 40V Supply Voltage /circle6 Internal 40V NDMOS Switch /circle6 Output Current 1A /circle6 Single Pin On/Off and Brightness Control Using DC Voltage or PWM /circle6 EC4304 to 95% Efficiency /circle6 Typical +/-5% LED Current Accuracy /circle6 Input Under Voltage Lockout /circle6 SOT23-5L 、DFN 3x3 8L 、SOT89-5L Package /circle6 RoHS Compliant and Halogen-Free
Applications
/circle6 Automotive LED Lighting /circle6 High Power LED Lighting /circle6 Indicator and Emergency Lighting /circle6 Architectural Lighting /circle6 Low Voltage Industrial Lighting /circle6 Signage and Decorative LED Lighting Functional Block Diagram
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Pin Configuration Typical Application Pin Name Pin Function LX Drain of NDMOS Switch. GND Ground for the IC. All voltages levels are measured with respect to this pin. ADJ Multi-Function ON/OFF and Brightness Control Pin: -Analog signal input for analog control of PWM dimming. -PWM signal input for digital PWM dimming. ISENSE Current Sense Pin: Sense LED String Current. VIN Power supply input pin. Connect a nominal (7V~40V) power supply to this pin. The power- on-reset (POR) function monitors the input voltage by this pin. It is recommended that a decoupling capacitor (4.7 µF or Higher X7R Ceramic capacitor) be connected to the GND for noise decoupling.
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Ordering/ Marking Information Part Number Package Marking Marking Information EC4304ANT2R SOT23-5 4304A LLLLLL LLLLLL is Lot No EC4304ANFNR DFN3x3-8 EC4304ANB9R SOT89-5L 4304A YWLLL YW ：Date Code LLL：Lot No
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Functional Description The EC4304 is a simple high-efficiency, continuous mode inductive step-down converter. The device operates with an input voltage range from 7V to 40V and delivers output current 1A. A high- side current-sense resistor sets the output current and a dedicated PWM dimming input enables pulsed LED dimming over a wide range of brightness levels. A high- side current-sensing scheme and an on-board current- setting circuitry minimize the number of external components which is required while delivering LED current with +5% accuracy, using a 1% sense resistor. Adjusting Output Current The device contains a low pass filter between the ADJ pin and the threshold comparator and an internal current limiting resistor between ADJ and the internal reference voltage. This allows the ADJ pin to be overdriven with either DC or pulse signals to change the VSENSE switching threshold and adjust the output current. Details of the different modes of adjusting output current are given in the applications section by: The value of the output current is 1A at 0.1 Ω (0.5A at 0.2 Ω) and this is a calculated output current when the ADJ terminal is 1.25V floating. Shutdown Mode Taking the ADJ pin to a voltage below 0.2V for more than approximately 100 µs will turn off the output, and supply current will fall to a low standby level of 20 µA nominal. Soft-Start The device has inbuilt soft-start action due to the delay through the PWM filter. An external capacitor from the ADJ pin to ground will provide additional soft-start delay, by increasing the time taken for the voltage on this pin to rise to the turn-on threshold and by slowing down the rate of rise of the control voltage at the input of the comparator. With no external capacitor, the time taken for the output to reach 90% of its final value is approximately 500 µs. Adding capacitance increases this delay by approximately 0.5ms/ nF. Inherent open-circuit LED protection If the connection to the LED(s) is open-circuited, the coil is isolated from the LX pin of the chip, so the chip will not be damaged. Unlike in many boost converters, where the back EMF may damage the internal switch by forcing the drain above its breakdown voltage.
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Absolute Maximum Rating ESD Rating (Note 2) Thermal Information Package Thermal Resistance (Note 3) Package Thermal Resistance (Note 4) Power Dissipation, P D @ T A = 25° C Recommended Operation Conditions Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution recommended. Note 3. θ JA is measured in the natural convection at T A = 25° C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Note 4. θJA is measured at T A = 25 °C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 5. The device is not guaranteed to function outside its operating conditions.
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch
Electrical Characteristics
(V IN = 12V, T A = 25 ℃, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Units Supply Input Supply Voltage Range V IN 7 - 40 V VIN POR Threshold V INRTH V IN Rising - 4.95 - V VIN POR Threshold V INFTH V IN Falling - 4.8 - V Quiescent Current with Output Off I_Q OFF ADJ pin grounded - 20 40 µA Quiescent Current with Output Switching I_Q ON ADJ pin floating f = 250KHz - 0.5 1.0 mA ISENSE Pin Current Sense Threshold Voltage VSENSE ISENSE pin with respect to VIN, ADJ = 1.25V 95 100 105 mV ISENSE Input Current ISENSE V SENSE = VIN-0,1 - - 1.0 µA Reference Reference Voltage VREF ADJ pin Voltage - 1.25 - V Reference Voltage Temperature Coefficient - 50 - ppm/V ADJ Pin ADJ Pin for DC Control Level V ADJ 0.3 - 2.5 V ADJ to Switch Device from On State to Off State V ADJ_OFF V ADJ falling 0.15 0.2 0.25 V ADJ to Switch Device from Off State to On State V ADJ_ON V ADJ rising 0.2 0.25 0.3 V 0 < V ADJ < VREF 135 - 250 KΩ ADJ to VREF Resistance R ADJ VADJ > VREF+100mV 13.5 - 25 K Ω ADJ Pin Low Frequency Duty Cycle Range DPWM (LF) PWM frequency < 500Hz 10 - 100 ADJ Pin High Frequency Duty Cycle Range DPWM (HF) PWM frequency >10KHz 16 - 100 LX pin LX Switch Current I LXmean EC4304A - - 1 A
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Parameter Symbol Test Conditions Min Typ Max Units LX R DS_ON R LX @I LX = 1A, EC4304A - 0.3 0.6 Ω LX Leakage Current - - 5 µA Minimum Switch ON Time T ON_min LX Switch ON - 240 - ns Minimum Switch OFF Time T OFF_min LX Switch OFF - 200 - ns Recommended Minimum Switch ON Time T ON_min_rec - 800 - ns Frequency Operation Frequency F LX ADJ pin floating, L=33 µH (0.093 Ω ) IOUT = 1A @ VLED=3.6V driving 1LED - 280 - kHz Recommended Maximum Operation Frequency F LXmax - - 1 MHz Duty Cycle Range of Output Switch of Operation Frequency D LX 30 - 70 % Internal Comparator Propagation Delay TPD - 50 - ns Soft-Start Soft-Start Time Time taken for output current to reach 90% of final value after voltage on ADJ pin has risen above 0.3V. - 500 - µs
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Typical Operation Characteristics
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Typical Operation Characteristics
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch Typical Operation Characteristics
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch
Package Information
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch SOT89-5L Package Informa tion DIMENSIONS IN MILLIMETERS SYMBOLS MIN NOM MAX A2 1.40 1.50 1.60 b 0.38 --- 0.47 b1 0.37 0.40 0.43 c 0.36 --- 0.46 c1 0.35 0.38 0.41 a 0.46 --- 0.56 a1 0.45 0.48 0.51 d 0.36 --- 0.46 d1 0.35 0.38 0.41 D 4.30 4.50 4.70 D1 1.70REF E 4.00 4.20 4.40 E1 2.30 2.50 2.70 e 1.50BSC L1 0.80 1.00 1.20
EC4304 1A, Hysteretic, High Brightness LED Driver with Internal Switch