LP8556 Datasheet, PDF (7/52 Pages) Texas Instruments – High-Efficiency LED Backlight Driver for Tablets

LP8556
www.ti.com
SNVS871B – JULY 2012 – REVISED SEPTEMBER 2012
Electrical Characteristics⁽¹⁾⁽²⁾
Limits in standard typeface are for T_A = 25 °C. Limits in boldface type apply over the full operating ambient temperature
range (-30 °C ≤ T_A ≤ +85 °C). Unless otherwise specified: VDD=12V, EN / VDDIO = 1.8V
Symbol
Parameter
Condition
Min
Typ
Max
Units
V_DDIO
V_DD
Supply voltage for digital I/Os
Input voltage for the internal LDO
Standby Supply Current
EN / VDDIO=0V, LDO disabled
1.62
2.7
3.6
V
20
V
1.6
μA
I_DD
Normal Mode Supply Current
LDO enabled, Boost disabled
LDO enabled, Boost enabled, no load
0.9
1.5
mA
2.2
3.65
f_OSC
Internal Oscillator Frequency
Accuracy
-4
-7
+4
+7
%
V_LDO
LDO Output Voltage
T_TSD
Thermal Shutdown Threshold
T_{TSD_hyst} Thermal Shutdown Hysteresis
V_DD ≥ 3.1V
2.7V ≤ V_DD < 3.1V
See ⁽³⁾
2.95
3.05
3.15
V_DD -
V
0.05
150
°C
20
°C
(1) All voltages are with respect to the potential at the GND pins.
(2) Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the
most likely norm.
(3) Guaranteed by design and not tested in production.
Boost Converter Electrical Characteristics⁽¹⁾
Symbol
Parameter
Condition
R_{DS_ON}
V_{BOOST_MIN}
Switch ON resistance
Boost minimum output
voltage
I_SW = 0.5A
VBOOST_RANGE = 0
VBOOST_RANGE = 1
V_{BOOST_MAX}
Boost maximum output
voltage
VBOOST_MAX = 100, VBOOST_RANGE = 0
VBOOST_MAX = 101, VBOOST_RANGE = 0
VBOOST_MAX = 110, VBOOST_RANGE = 0
VBOOST_MAX = 111, VBOOST_RANGE = 0
VBOOST_MAX = 010, VBOOST_RANGE = 1
VBOOST_MAX = 011, VBOOST_RANGE = 1
VBOOST_MAX = 100, VBOOST_RANGE = 1
VBOOST_MAX = 101, VBOOST_RANGE = 1
VBOOST_MAX = 110, VBOOST_RANGE = 1
VBOOST_MAX = 111, VBOOST_RANGE = 1
I_{LOAD_MAX}
V_OUT/V_IN
f_SW
Maximum continuous output
load current
Conversion ratio⁽²⁾
Switching frequency
V_IN = 3V, V_OUT = 18V
V_IN = 3V, V_OUT = 24V
V_IN = 3V, V_OUT = 30V
f_SW = 625 kHz
f_SW = 1250 kHz
BOOST_FREQ = 00
BOOST_FREQ = 01
BOOST_FREQ = 10
V_OVP
Over-voltage protection
voltage
VBOOST_RANGE = 1
V_UVLO
V_IN under-voltage lockout
threshold
UVLO_EN=1
UVLO_TH = 0, falling
UVLO_TH = 1, falling
V_{UVLO_hyst} V_UVLO hysteresis
V_UVLO[rising]
V_UVLO[falling]
UVLO_TH = 0
UVLO_TH = 1
t_PULSE
Switch minimum pulse width no load
Min
Typ Max
0.19
7
16
19.0
21
22
24.0
25
27
28.0
30
32
32
34
37
17.9
21
23.1
22.8
25
27.2
27.8
30
31.5
32.7
34.5 36.6
37.2
39
40.8
41.8
43
44.2
220
160
120
15
12
312
625
1250
V_BOOST
+ 1.6V
2.5
5.2
50
100
50
Units
Ω
V
V
V
mA
kHz
V
V
mV
ns
(1) Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the
most likely norm.
(2) Guaranteed by design and not tested in production.
Copyright © 2012, Texas Instruments Incorporated
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