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PDF ISL78419 Data sheet ( Hoja de datos )
| Número de pieza | ISL78419 | |
| Descripción | Integrated Automotive TFT-LCD Power Supply Regulator | |
| Fabricantes | Intersil Corporation | |
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Integrated Automotive TFT-LCD Power Supply Regulator
ISL78419
The ISL78419 is an integrated power management IC (PMIC) for
TFT-LCDs used in central display, rear seat entertainment and
virtual dashboards. The device integrates a boost converter for
generating AVDD, an LDO regulator for VLOGIC. VON and VOFF are
generated by a charge pump driven by the switch node of the
boost converter. The ISL78419 also includes a VON slice circuit,
reset function, and a high performance VCOM amplifier with a
Digitally Controlled Potentiometer (DCP) that is used as a VCOM
calibrator.
The AVDD boost converter features a 1.5A/0.18Ω boost FET with
600kHz/1200kHz switching frequency.
The integrated logic LDO includes a 350mA FET for driving the low
voltage needed by external digital circuitry.
The gate pulse modulator can control the gate voltage up to 30V,
and both the rate and slew delay times are selectable.
The supply monitor generates a reset signal when the system is
powered down based on a user selected threshold level
(programming resistor).
The ISL78419 provides a digitally controlled VCOM output using
I2C interface. One VCOM amplifier is also integrated in the chip to
provide a fast slewing 150mA drive (sourcing or sinking). The
output of the VCOM is powered up with the voltage stored at the
last programmed 8-bit (internal) EEPROM setting.
The ISL78419 is rated to operate over the temperature range
of (-40°C to +105°C) and is qualified according to AEC Q100.
Features
• 2.5V to 5.5V input
• 1.5A, 0.18Ω integrated boost FET
• VON/VOFF supplies generated by charge pumps driven by the
boost switch node
• LDO for VLOGIC channel
• 600kHz/1200kHz selectable switching frequency
• Integrated gate pulse modulator
• Reset signal generated by supply monitor
• Integrated VCOM amplifier
• DCP
- I2C serial interface, address: 0101000, MSB left
- Wiper position stored in 8-bit nonvolatile memory and
recalled on power-up
- Endurance, 1,000 data changes per bit
• UVLO, UVP, OVP, OCP, and OTP protection
• Pb-free (RoHS compliant)
• 28 Ld 4x5 QFN
• AEC Q100 qualified
Applications
• Automotive TFT displays
- Central displays, rear seat entertainment and dashboards
Pin Configuration
ISL78419 (28 LD 4x5 QFN)
TOP VIEW
28
FB 1
PGND 2
CE 3
RE 4
VGH 5
VGHM 6
VFLK 7
VDPM 8
27 26 25 24
GND
THERMAL
PAD
23
22 L_IN
21 CD2
20 L_OUT
19 RESET
18 ADJ
17 VDIV
16 NEG
15 VOUT
9 10 11 12 13 14
January 24, 2014
FN8292.2
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2012, 2014. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
1 page  
ISL78419
Absolute Maximum Ratings
RE, VGHM, GPM_LO and VGH to GND . . . . . . . . . . . . . . . . . . . . -0.3 to +36V
LX, AVDD, POS, NEG, VOUT to GND . . . . . . . . . . . . . . . . . . . . . -0.3 to +18V
Voltage Between GND and PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±0.5V
All Other Pins to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0V
ESD Rating
Human Body Model (Tested per JESD22-A114E) . . . . . . . . . . . . . . . . 2kV
Machine Model (Tested per JESD22-A115-A) . . . . . . . . . . . . . . . . . 200V
Charged Device Model (Tested per JESD22-C101). . . . . . . . . . . . . . . 1kV
Latch Up (Tested per JESD-78B; Class 2, Level A) . . . . . . . . . . . . . . 100mA
Thermal Information
Thermal Resistance (Typical)
θJA (°C/W) θJC (°C/W)
28 Ld 4x5 QFN Package (Notes 4, 5). . . . .
38
4.5
Ambient Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +105°C
Functional Junction Temperature . . . . . . . . . . . . . . . . . . . .-40°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Lead Temperature During Soldering . . . . . . . . . . . . . . . . . . . . . . . . +260°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +105°C
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5V to 5.5V
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product
reliability and result in failures not covered by warranty.
NOTES:
4. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech
Brief TB379.
5. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside.
Electrical Specifications VIN = ENABLE = 3.3V, AVDD = 8V, VLDO = 2.5V, VON = 24V, VOFF = - 6V. Boldface limits apply over the
operating temperature range, -40°C to +105°C.
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
(Note 6)
TYP
(Note 7)
MAX
(Note 6) UNITS
GENERAL
VIN VIN Supply Voltage Range
2.5 3.3 5.5 V
IS_DIS
VIN Supply Currents when Disabled
VIN < UVLO
390 500 µA
IS VIN Supply Currents
ENABLE = 3.3V, overdrive AVDD and VGH
0.7 1.0 mA
IENABLE ENABLE Pin Current
ENABLE = 0V
0 µA
LOGIC INPUT CHARACTERISTICS - ENABLE, FLK, SCL, SDA, FREQ
VIL Low Voltage Threshold
VIH High Voltage Threshold
RIL Pull-Down Resistor
INTERNAL OSCILLATOR
Enable, FLK, FREQ
1.75
0.85
1.25
0.65
1.65
V
V
MΩ
FOSC
Switching Frequencies
AVDD BOOST REGULATOR
FREQ = low, TA = +25°C
FREQ = high, TA = +25°C
550
1100
600
1200
650
1300
kHz
kHz
DAVDD/
DIOUT
AVDD Load Regulation
50mA < ILOAD < 250mA
0.2 %
DAVDD/
DVIN
AVDD Line Regulation
ILOAD = 150mA, 2.5V < VIN < 5.5V
0.15 %
VFB
IFB
rDS(ON)
ILIM
DMAX
EFF
Feedback Voltage (VFB)
FB Input Bias Current
Switch ON-resistance
Switch Current Limit
Max Duty Cycle
ILOAD = 100mA, TA = +25°C
TA = +25°C
Freq = 1.2MHz
Freq = 1.2MHz, IAVDD = 100mA
0.792
0.8
0.808
V
100 nA
180 260 mΩ
1.125
1.5
1.875
A
80 90
%
91 %
5 FN8292.2
January 24, 2014
5 Page 
ISL78419
Applications Information
Enable Control
With VIN > UVLO, only the Logic output channel is activated. All
other functions in ISL78419 are shut down when the enable pin
is pulled down. When the voltage at the enable pin reaches high
threshold, the whole chip turns on.
Frequency Selection
The ISL78419 switching frequency can be user selected to
operate at either constant 600kHz or 1.2MHz. Lower switching
frequency can save power dissipation at very light load
conditions. Also, low switching frequency more easily leads to
discontinuous conduction mode, while higher switching
frequency allows for smaller external components, such as
inductor and output capacitors, etc. Higher switching frequency
will get higher efficiency within some loading ranges depending
on VIN, VOUT, and external components, as shown in Figure 1.
Connecting the FREQ pin to GND sets the PWM switching
frequency to 600kHz, or connecting FREQ pin to VIN for 1.2MHz.
Soft-Start
The soft-start is provided by an internal current source to charge
the external soft-start capacitor. The ISL78419 ramps up the
current limit from 0A up to the full value, as the voltage at the SS
pin ramps from 0V to 0.8V. Hence, the soft-start time is 3.2ms
when the soft-start capacitor is 22nF, 6.8ms for 47nF and
14.5ms for 100nF.
Operation
The boost converter is a current mode PWM converter operating
at either 600kHz or 1.2MHz. It can operate in both discontinuous
conduction mode (DCM) at light load and continuous conduction
mode (CCM). In continuous conduction mode, current flows
continuously in the inductor during the entire switching cycle in
steady state operation. The voltage conversion ratio in
continuous current mode is given by Equation 1:
V-----B----o---o---s---t
VIN
=
------1-------
1–D
(EQ. 1)
Where D is the duty cycle of the switching MOSFET.
The boost regulator uses a summing amplifier architecture
consisting of gm stages for voltage feedback, current feedback
and slope compensation. A comparator looks at the peak
inductor current cycle-by-cycle and terminates the PWM cycle if
the current limit is reached.
An external resistor divider is required to divide the output
voltage down to the nominal reference voltage. Current drawn by
the resistor network should be limited to maintain the overall
converter efficiency. The maximum value of the resistor network
is limited by the feedback input bias current and the potential for
noise being coupled into the feedback pin. A resistor network in
the order of 60kΩ is recommended. The boost converter output
voltage is determined by Equation 2:
VBoost
=
R-----1-----+----R-----2-
R2
×
VF
B
(EQ. 2)
The current through the MOSFET is limited to 1.5APEAK.
This restricts the maximum output current (average) based on
Equation 3:
IOMAX
=
⎛
⎝
IL
MT
–
-Δ--2--I--L-⎠⎞
×
V-----I--N--
VO
(EQ. 3)
Where ΔIL is the peak-to-peak inductor ripple current, and is set
by Equation 4:
ΔIL
=
-V----I--N--
L
×
-D--
fs
(EQ. 4)
Where fS is the switching frequency (600kHz or 1.2MHz).
Capacitor
An input capacitor is used to suppress the voltage ripple injected
into the boost converter. The ceramic capacitor with a
capacitance larger than 10µF is recommended. The voltage
rating of the input capacitor should be larger than the maximum
input voltage. Some input capacitors are recommended in Table 1.
TABLE 1. BOOST CONVERTER INPUT CAPACITOR RECOMMENDATION
CAPACITOR
SIZE MFG
PART NUMBER
10µF/6.3V
10µF/16V
0603
1206
TDK
TDK
C1608X5R0J106M
C3216X7R1C106M
10µF/10V
22µF/10V
0805
1210
Murata
Murata
GRM21BR61A106K
GRB32ER61A226K
Inductor
The boost inductor is a critical part that influences the output
voltage ripple, transient response, and efficiency. Values of
3.3µH to 10µH are used to match the internal slope
compensation. The inductor must be able to handle the following
average and peak currents shown in Equation 5:
ILAVG
ILPK =
=
----I--O-------
1–D
ILAVG
+
-Δ----I--L-
2
(EQ. 5)
Some inductors are recommended in Table 2 for different design
considerations.
Rectifier Diode
A high-speed diode is necessary due to the high switching
frequency. Schottky diodes are recommended because of their
fast recovery time and low forward voltage. The reverse voltage
rating of this diode should be higher than the maximum output
voltage. The rectifier diode must meet the output current and
peak inductor current requirements. Table 3 shows some
recommendations for boost converter diode.
TABLE 2. BOOST CONVERTER INDUCTOR RECOMMENDATION
DIMENSIONS
INDUCTOR (mm)
MFG
PART
NUMBER
NOTE
10µH/ 8.3x8.3x4.5 Sumida CDR8D43-100NC
4Apeak
Efficiency
optimization
6.8µH/ 5.0x5.0x2.0 TDK PLF5020T-6R8M1R8
1.8Apeak
10µH/ 6.6x7.3x1.2 Cyntec PCME061B-100MS
2.2Apeak
PCB
space/profile
optimization
11 FN8292.2
January 24, 2014
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet ISL78419.PDF ] | |
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