EC4503|White LED Set-Up Converter

EC4503|White LED Set-Up Converter


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White LED Set-up Converter

EC4503

 

 

General Description

 

 

 

The EC4503 is a current-mode and fixed frequency

Boost converter with an integrated N-FET to drive 

white LEDs.

The series connection allows the LED current to be 

identical for uniform brightness. Its low on-resistance 

of  NFET and low feedback voltage reduce power loss

 and achieve high efficiency. Fast switching frequency (1.5MHz typical) allows using small size inductor and both of input and output capacitors. An over voltage protection function, which monitors the output voltage via OVP pin,stops switching of the IC if the OVP voltage exceeds the over voltage threshold. An internal soft-start

circuit eliminates the inrush current during start-up.

The EC4503 also integrates under-voltage lockout,

Overtemperature protection, and current limit circuits to

Protect the IC in abnormal conditions.

The EC4503 is available in a SOT-23-6 packages.

Features

 

●Wide Input Voltage from 2.7V to 6V

●0.2V Reference Voltage

●Fixed 1.5MHz Switching Frequency

PWM Brightness Control with Wide Frequency 

Range of 100Hz to 100kHz 

BuildIn Power MOSFET : 0.2Ω

Open‐LED Protection 

UnderVoltage Lockout Protection 

Over‐Temperature Protection 

<1mA Quiescent Current during Shutdown 

●SOT‐23‐6 Packages

● Lead Free and Green Devices Available

●(RoHS Compliant)

 

 

Applications

 

 

●White LED Display Backlighting

Cell Phone and Smart Phone

PDA, PMP, MP3

Digital Camera

 

 

 

 

White LED Set-up Converter

EC4503

 

Pin Assignments 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pin Description

 

Pin Number

Pin Name

Description

1

LX 

Switch pin. Connect this pin to inductor/diode here. 

2

GND 

Ground 

3

FB 

Feedback Pin. Connect this pin to cathode of the lowest LED and currentsense resistor 

(R1). Calculate resistor value according to R1=VREF/ILED 

4

EN 

Enable Control Input. Forcing this pin above 1.0V enables the device, or forcing this pin 

below  0.4V  to  shut  it  down.  In  shutdown,  all  functions  are  disabled  to  decrease  the 

supply current below A. Do not leave this pin floating. 

5

OVP 

Converter Output and OverVoltage Protection Input Pin. 

6

IN 

Main  Supply  Pin.  Must  be  closely  decoupled  to  GND  with  a  4.7μF  or  greater  ceramic 

capacitor. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ordering Information

 

Part Number

Package

Marking

Marking Information

EC4503NNB3R

SOT23-6

4503f

  • Starting with underlined 5, a bar is for production year 2012. The next bar is mark on top of 0 is for year 2013. The next bar is mark on bottom of 0 is for year 2014. The next bar is mark on top of 3 is year for 2015. The ​​ naming pattern continues with consecutive characters for later years.

  • f is the week of production. The big character of A~Z is for the week of 1~26, and small a~z is for the week of 27~52.

EC4503ANB3R

SOT23-6

4503A

LLLLL

  • LLLLL:Lot No

Functional Block Diagram 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

White LED Set-up Converter

EC4503

Function Block Diagram of ​​ EC4503

 

Absolute Maximum Ratings

Symbol

Parameter

Rating

Unit

VIN

VIN Supply Voltage (VIN to GND)                                                                                                           

-0.3 ~ 7

V

VLX

FB, EN to GND                                                                                                                                         

-0.3 ~ VIN

V

LX to GND Voltage                                                                                                                                  

-0.3 ~ 27.5

V

VOVP

OVP to GND                                                                                                                                            

-0.3 ~ 27.5

V

PD

Power Dissipation

Internally Limit

W

TJ

Maximum Junction Temperature

150

TSTG

Storage Temperature                                                                                                                              

-65 ~ 150

TSDR

Maximum Lead Soldering Temperature, 10 Seconds

260

 

Recommended Operating Conditions

 

Symbol

Parameter

Typical    Value

Unit

θJA 

Junction-to-Ambient Resistance in Free Air 

220                                                                                      

/W

θJC 

Junction-to-Case Resistance

120                                                                                    

/W

VIN 

VIN Supply Voltage(VIN to GND) 

2.76

V

VOVP 

VOUT to GND

VIN22

V

CIN 

Input Capacitor

4.7~

uF

COUT 

Output Capacitor

4.7~

uF

L1 

Converter Output Inductor

2.210

uH

TA 

Ambient Temperature                                                                                                        

-40~85

TJ 

Junction Temperature                                                                                                        

-40~125

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Electrical Characteristics

The following specifications apply for VIN =3.6V TA=25 oC, unless specified otherwise. 

 

 

 

 

 

 

Symbol

 

Parameter

Test Conditions

EC4503

Unit

Min.

Typ.

Max.

VIN 

Input Voltage Range 

 

2.7

​​ 

6

V

IDD1                               

Input DC Bias Current

VFB = 0.4V, no switching

 

300

​​ 

µA

IDD2                

VFB = 0V,  switching                                 -

​​ 

2

5

mA

ISD 

EN = GND                                                   -

​​ 

​​ 

1

µA

​​ 

UVLO Threshold Voltage 

VIN Rising

2.0

2.2

2.4

V

​​ 

UVLO Hysteresis Voltage                  

VIN Failing

50

100

150

mV

               

VREF 

Regulated Feedback Voltage

VIN=2.7V~6V,TA = 25°C

0.185

0.2

0.215

V

VIN=2.7V~6V,

TA = -40 ~ 85

 

0.18

​​ 

0.22

IFB 

FB Input Current                            

 

-50

---

50

nA

FSW 

Switching Frequency 

​​ 

1.25

1.5

1.75

MHz

RON 

Power Switch On Resistance             

-

​​ 

0.2

​​ 

Ω

ILIM

Power Switch Current-Limit

 

 

2

 

A

 

LX Leakage Current 

VEN=0V, VLX=0V or 6V, VIN = 6V

-1

 

1

µA

DMAX 

LX Maximum Duty Cycle                   

 

92

95

98

%

​​ 

Over-Voltage Threshold

Vout Rising,( EC4503ANB3R)

22

24

27.5

V

Vout Rising, (EC4503NNB3R)

14.5

16

20

V

 

OVP Voltage Hysteresis

Vout Failing

 

3

 

V

 

OVP Leakage Current 

VOVP =20V                                   -

​​ 

50

​​ 

nA

​​ 

Enable Voltage Threshold 

VEN Rising

1

​​ 

​​ 

V

 

Shut-down Voltage Threshold

VEN Failing

 

 

0.4

V

​​ 

EN Leakage Current 

VEN= 0~6V, VIN = 6V

      -2

​​ 

2 

µA

 

EN Minimum on pluse-width

VEN= 0~6V, VIN=6V, PWM

 

800

 

ns

TOTP

Over-Temperature Protection

TJ Rising                                                      -

​​ 

150           -

​​ 

 ​​ ​​ ​​ ​​​​ 

 

Over-Temperature Protection  

 

TJ Failing 

 ​​ ​​​​ 

 ​​ ​​ ​​ ​​ ​​​​ 40

 ​​ ​​ ​​​​ 

 ​​ ​​ ​​ ​​​​ 

 

White LED Set-up Converter

EC4503

 

 

Typical Performance ​​ Characteristics

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

White LED Set-up Converter

EC4503

 

 

Typical Performance ​​ Characteristics(Cont.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operating Waveforms