EC4513 E-CMOS | Alldatasheet

Document overview

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Technical content

Features

  • Wide Input Voltage Range from 2.7V to 21V
  • High Current‐Limit up to 3.5A
  • 0.5V Reference Voltage with ±3% System Accuracy
  • 50mΩ Integrated N‐FET
  • Fixed 1.2MHz Switching Frequency
  • High Efficiency up to 95%
  • Open‐LED Protection
  • Under‐Voltage Lockout Protection
  • ALS Control Input Pin
  • Over‐T emperature Protection
  • Low Shutdown Current: <1mA
  • 3mmx3mm DFN‐10 Package
  • Lead Free and Green Devices Available

Applications

  • Display Backlighting
  • Automotive
  • LCD Monitors
  • Notebook Displays
  • Portable Displays Pin Assignments

High Efficiency 1MHz, Step up Regulator EC4513 Pin Description Pin Number Pin Name

Description

1 FB Regulator Feedback Pin. Connect a current sense resistor to GND to set the LED Current. 2 COMP Error Amplifier Output. Connect a 0.22uF capacitor for compensation and soft-start. When EN is pulled low, an internal switch will discharge the COMP voltage to 0V 3 OVP Output Over Voltage Monitor Pin. Tie to VOUT for OVP function. EN Enable Control Input. Pull EN above 2.4V to enable the device. Pull EN below 0.4V to disable the device. The EN Pin cannot be left floating. 5 PGND Power GND. Source of the internal N-channel power MOSFET. 6 LX Internal Power MOSFET Drain. 7 VIN Supply Voltage Input. 8 BP Output of The Internal 5V Regulator. Connect a 1uF bypass capacitor to GND Do not apply an external load to BP 9 GND Signal Ground. 10 ALS Ambient Light Sensor Input. Allow the light sensor to control the FB voltage for LED dimming. If the ALS function is not used, tie the ALS pin to BP pin.

Ordering Information

Part Number Package Marking Marking Information EC4513NNFNR DFN 3x3-10 4513 LLLL 1.LLLL：Last four number of Lot No

High Efficiency 1MHz, Step up Regulator EC4513 Function Block Diagram Function Block Diagram of EC4513

High Efficiency 1MHz, Step up Regulator EC4513 Absolute Maximum Ratings Recommended Operating Conditions Symbol Parameter Rating Unit VIN VIN Pin toGND VIN pin to GND -0.3 ~ 30 V VLX VIN Pin toGND LX pin to PGND -0.3 ~ 30 V VOVP VIN Pin toGND OVP pin to GND -0.3 ~ 30 V VBP VIN Pin toGND BP pin to GND -0.3 ~ 6 V VEN VIN Pin toGND EN pin to GND -0.3 ~ 30 V VALS VIN Pin toGND ALS pin to GND -0.3 ~ 6 V VIN Pin toGND PGND to GND -0.3 ~ +0.3 V TJ VIN Pin toGND Maximum Junction Temperature 150 ℃ TSTG VIN Pin toGND Storage Temperature Range -65 to 150 ℃ TL VIN Pin toGND Maximum Lead Soldering Temperature,10 seconds 260 ℃ Symbol Parameter Typical Value Unit VIN VIN Supply Voltage(VIN=BP) 2.7‐5.5 V VIN Supply Voltage(BP is Open) 3.7~21 VOUT Output Voltage Up to 30 V TA Operating Ambient Temperature -40~85 ℃ TJ Operating Junction Temperature -40~125 ℃

High Efficiency 1MHz, Step up Regulator EC4513

Electrical Characteristics

The following specifications apply for VIN =6V TA=25 oC, unless specified otherwise. Symbol Parameter Test Conditions EC4513 Unit Min. Typ. Max. INPUT SUPPLY CURRENT AND UVLO BP Under Voltage Lockout Threshold VIN rising 2.4 2.5 2.6 V UVLO Hysteresis 100 mV IVIN VIN Supply Current EN=5V, switching 9 15 mA EN=0V 1 uA ERROR AMPLIFIER gm Error Amplifier Transconductance 350 uA/V ICOMP COMP Output Current sourcing and sinking, VCOMP=1.5V uA VFB FB Voltage 485 500 515 mV Minimum FB Voltage VALS=0.3V 188 200 212 mV IFB FB Input Bias Current ‐ 1 uA FB Line Regulation VIN=2.7V to 21V 0.02 0.04 %/V INTERNAL POWER SWITCH Power Switch Current- Limit 2.5 3.5 4.5 A RDS(ON) Power Switch On Resistance 50 100 mΩ LX Leakage Current VLX=30V 1 uA FSW Switching Frequency 0.9 1.2 1.5 MHz DMAX LX Maximum Duty Cycle 92 95 98 % ALS ALS Ratio VALS=1V, VALS/VFB 2.9 3 3.1 V/V ALS Pin Leakage VALS=5V 1 uA OUTPUT OVER-VOLTAGE PROTECTION Over-Voltage Threshold 30 32 34 V OVP Hysteresis 2 3 4 V OVP Leakage Current 30 uA CONTROL LOGIC PIN EN High-Level Input Voltage 2.4 V EN Low-Level Input Voltage 0.4 V EN Leakage Current VEN=21V 1 uA THERMAL SHUTDOWN Thermal Shutdown Threshold 150 Thermal Shutdown Hysteresis

High Efficiency 1MHz, Step up Regulator EC4513 Typical Performance Characteristics

High Efficiency 1MHz, Step up Regulator EC4513 Typical Performance Characteristics(Cont.)

High Efficiency 1MHz, Step up Regulator EC4513 Typical Performance Characteristics(Cont.)

High Efficiency 1MHz, Step up Regulator EC4513 Operating Waveforms

Figure 3. General Boost Converter Application

High Efficiency 1MHz, Step up Regulator EC4513 Function Description Output Over-Voltage Protection If the FB pin is shortened to the ground or an LED fails open circuit, output voltage in BOOST mode can increase to potentially damaging voltages. An optional over-voltage protection circuit can be enabled by connection of the OVP pin to the output voltage. The device will stop switching if the output voltage exceeds OVP high threshold and restart when the output voltage falls below OVP low threshold. During sustained OVP fault conditions, VOUT will saw-tooth between the upper and lower threshold voltages at a frequency determined by the magnitude of current available to discharge the output capacitor. Note that the OVP pin must be connected to output voltage for OVP function. Ambient Light Sensor Interface The EC4513 provides the ALS pin to simplify the interface to an ambient light sensor. The ambient light sensor detects the ambient light and yields a current which is related to the illuminance. Connect a load resistor from the current output of ambient light sensor to ground to provide an output voltage to ALS pin. The ALS voltage will be divided by an internal divider circuit, and the divided ALS voltage will replace the internal reference voltage.The LED current can be calculated by the following equation: Note that the maximum FB voltage is set to 0.5V, and minimum FB voltage is set to 0.2V. If the divided ALS voltage is over 0.5V or less 0.2V, the LED current is limited at: where R1 is the resistor from FB to GND. Feedback resistor dividers R1 and R2: Choose R1 and R2 to program the proper output voltage. To minimize the power consumption under light loads, it is desirable to choose large resistance values for both R1 and R2. A value of between 10k and 1M is recommended for both resistors. If R1=200k is chosen, then R2 can be calculated to be: Enable/Disable Pull the EN above 2V to enable the device and pull EN pin below 0.4V to disable the device. In shutdown mode, the internal Control circuits are turned off, the quiescent current is below 1uA. Thermal Shutdown When the junction temperature exceeds 150℃, the internal thermal sensor circuit will disable the device and allow the device to cool down. When the device’s junction temperature cools by 50℃, the internal thermal sense circuit will enable the device,resulting in a pulsed output during continuous thermal protection.Thermal protection is designed to protect the IC in the event of over temperature conditions. For normal operation, the junction temperature cannot exceed TJ=+125 ℃. Internal 5V LDO The EC4513 provides an internal 5V LDO for the control circuitry, and the output of the internal LDO is BP pin. In normal operation, connect a 1uF or greater capacitor to GND is recommended. The internal LDO cannot supply any more current than is required to operate the EC4513. Therefore, do not apply any external load to BP pin. In applications, where the VIN is less than 5.5V, BP should be tied to VIN through a 10Ω resistor.

High Efficiency 1MHz, Step up Regulator EC4513

Application Information

Connecting More LED Strings The EC4513 can drive 8 LED strings in parallel and up to 8 LEDs per string (VF<3.5V). Each string must have the same number of LEDs. In the applications that have the same total number of LEDs, more strings and less LEDs in series are more efficiency than less strings and more LEDs in series. Brightness Control The method for dimming the LEDs is to apply a PWM voltage through an RC filter into the FB pin. The RC filter is used to convert the PWM voltage into an analog voltage. The values of the R and C depend upon the frequency of the PWM voltage and the amount of allowable ripple voltage on FB pin. The LED current is proportional to the PWM duty cycle. 0 % duty delivers maximum LED current and 100% duty delivers minimum LED current. The values of R1 and R2 are calculated by the following equations: where: ILED(max) is the maximum LED current ILED(min) is the minimum LED current VADJ(high) is the maximum PWM voltage level VADJ(low) is the minimum PWM voltage level VFB is the FB pin Voltage Figure 4. Dimming with the PWM Voltage and higher series resistance. reverse voltage must exceed output voltage. noise. The typical value for input capacitor is 2.2uF to 10uF.

The correct PCB layout is important for all switching converters. COMP pins. The trace from diode to the LEDs may be longer. from FB to GND should be close to the FB pin as possible. through several thermal vias to improve heat dissipation. Figure 5. Layouy Guidelines

High Efficiency 1MHz, Step up Regulator EC4513

Package Information

DFN3x3-10 Package Outline Dimensions