LRC LR246 Schematics
LESHAN RADIO COMPANY, LTD.
LR246
LR246 is a step-up DC/DC converter
specifically designed to drive white LED with a
constant current. It can drive two,three,or four
LEDS. It switches at 1.2MHz and use tiny
external components. The output capacitor can
be as small as 0.22uF,which can save space
and cost versus alternative solutions. Feedback
White LED Step-Up Converter
voltage is as low as 95mV. Built-in OverVoltage
function.
Absolute maximum ratings
Parameter symbol value unit
Supply Voltage V
Feedback Voltage FB 10 V
Switch Voltage SW 20 V
CE Voltage V
Operating temperature range T
Storage temperature range R
Junction temperature T
¾ OverVoltage Function
¾ Fast 1.2MHz Switching Frequency
¾ Requires Only 0.22uF Output Capacitor
¾ Inherently Matched LED Current
¾ High Efficiency: 85% Typical
¾ 2.5V to 10V VIN ranges
¾ Drives Up to Four series LEDs with a Li-lon cell
¾ Uses Very Tiny Inductors
¾ SOT-26 Package
IN
CE
opr
stg
j
10 V
10 V
-25 to +70 ℃
-55 to +150 ℃
125 ℃
Pin name
1
2
3 4
Description Symbol Description Symbol
6
5
1：Switch
SW
2：GND
3：Feedback
GND
FB
6：Supply
V oltage
5：Over
V oltage
4：Start-Up
VIN
OVP
CE
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Block Diagram
Fosc
PIN6(VIN)
PIN4
SHUTDOWN
VREF
PWM
CONTROL
+
SLOPE
+
-
+
gm
-
+
SENSECURRENT
COMP
LESHAN RADIO COMPANY, LTD.
LR246
PIN1(SW)
PIN5(OVP)
0
0
0
PIN2(GND)
PIN3(FB)
D246
2/8
Electrical Characteristics
LESHAN RADIO COMPANY, LTD.
LR246
T
= 25 , ℃ VIN=3V，VCE=3V,unless otherwise specified.
amb
Parameter Test Conditions / Pins Min Type Max Unit
Minimum Operating Voltage 2.5 V
Maximum Operating Voltage 10 V
Feedback Voltage
FB Pin Bias Current 50 100 200 nA
Supply Current
Switching Frequency 0.8 1.2 1.6 MHz
Maximum Duty Cycle 85 90 %
OVP Protection 27 V
Switch Current Limit 320 mA
Switch V
CESAT
ISW=100mA,
Duty Cycle=66%
=0V
V
CE
ISW =250mA 350 mV
86 95 104 mV
1.9
2.5 1 mA
0.1
uA
Switch Leakage Current VSW=5V 0.01 5 uA
CE Voltage High 1.5 V
CE Voltage Low 0.4 V
CE Pin Bias Current 65 uA
T ypical Application
HI
VCC
C1
1u
Fosc
PIN6(VIN)
PIN4
SHUTDOWN
VREF
PWM
CONTROL
L1
1 2
22uH
CURRENT
+
SLOPE
+
-
+
gm
-
+
COMP
SENSE
0
PIN2(GND)
PIN1(SW)
PIN5(OVP)
0
0
PIN3(FB)
D4
1 2
1k
C2
0.22u
D1
D1
D1
R1
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