LTC3453_15 Datasheet, PDF (4/12 Pages) Linear Technology – Synchronous Buck-Boost High Power White LED Driver

LTC3453
TYPICAL PERFOR A CE CHARACTERISTICS
Efficiency vs LED Current
100
FRONT PAGE APPLICATION
P_LED/P_IN, V_IN = 3.6V, T_A = 25°C
90
Output Voltage Ripple
80
20mV/DIV
AC COUPLED
70
60
50
100 150 200 250 300 350 400 450 500
LED CURRENT (mA)
3453 G07
5µs/DIV
FRONT PAGE APPLICATION
V_IN = 3.6V
I_LED = 150mA
Startup Transient
CH1, V_OUT
2V/DIV
3453 G08
0V
CH2, EN1
1V/DIV
0V
1ms/DIV
FRONT PAGE APPLICATION
V_IN = 3.6V
I_LED = 150mA
3453 G09
PI FU CTIO S
V_IN (Pin 1): Signal Voltage Input Supply Pin [2.7V ≤ V_IN ≤
5.5V]. Recommended bypass capacitor to GND is 2.2µF
ceramic or larger. Connect to PV_IN (Pin 16).
EN1 (Pin 2): Enable Input Pin for I_SET1 Current.
I_SET1 (Pin 3): White Led Current Programming Pin. A
resistor to ground programs each current source output to
I_LED = 384(0.8V/R_ISET1). This amount of current adds to
any amount set by EN2/I_SET2 if also used.
LED1 to LED4 (Pins 4, 6, 7, 9): Individual Low Dropout
Current Source Outputs for White LED Current Biasing.
Connect each white LED between V_OUT and an individual
LEDx pin. Unused LEDx outputs should be connected to
V_OUT.
GND (Pins 5 and 8): Signal Ground Pin. Connect to PGND
(Exposed Pad).
I_SET2 (Pin 10): White Led Current Programming Pin. A
resistor to ground programs each current source output to
I_LED = 384(0.8V/R_ISET2). This amount of current adds to
any amount set by EN1/I_SET1 if also used.
EN2 (Pin 11): Enable Input Pin for I_SET2 Current.
V_C (Pin 12): Compensation Point for the Internal Error
Amplifier Output. Recommended compensation capacitor
to GND is 0.1µF ceramic or larger.
V_OUT (Pin 13): Buck-Boost Output Pin. Recommended
bypass capacitor to GND is 4.7µF ceramic.
SW2 (Pin 14): Switching Node Pin. Connected to internal
power switches C and D. External inductor connects
between SW1 and SW2. Recommended value is 4.7µH.
SW1 (Pin 15): Switching Node Pin. Connected to internal
power switches A and B. External inductor connects
between SW1 and SW2. Recommended value is 4.7µH.
PV_IN (Pin 16): Power Voltage Input Supply Pin. Connect to
V_IN (Pin 1).
Exposed Pad (Pin 17): Power Ground Pin. Connect to
GND (Pin 8) and solder to PCB ground for optimum
thermal performance.
3453fa
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