|
|
PDF IW7032 Data sheet ( Hoja de datos )
| Número de pieza | IW7032 | |
| Descripción | 32-Channel LED Driver | |
| Fabricantes | iWatt | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de IW7032 (archivo pdf) en la parte inferior de esta página. Total 30 Páginas | ||
|
No Preview Available !
iW7032
32-Channel LED Driver for LCD Panel Backlighting
1.0 Features
●● Fully integrated power FET with minimum external
components
●● Proprietary digital power management and patented
adaptive switch mode LED driver
●● 32-channel output each at 56 V with 9 V to 28 V input
supply voltage range
●● Dynamic external Boost or Buck controller interface to
optimize system power efficiency
●● Serial Peripheral Interface (SPI) compatible for high
bandwidth PWM-based dynamic local dimming
●● Per channel current up to 120 mA average current,
with non-adaptive-switch peak current of 120 mA for
local dimming and 192 mA for scanning mode, and with
adaptive-switch peak current up to 60% higher.
●● LED failure (open and short-circuit) detection
●● LED brightness local dimming, scanning, and 3D game
mode controlled by SPI interface
●● PWM dimming range from 1% to 99.9% with 10-bit
resolution
●● Vsync synchronized PWM
●● PWM dimming frequency from 120Hz to 2.4 kHz in
NTSC; 100Hz to 2.4kHz in PAL; and 96Hz to 2.4kHz
in 3D game mode with 5-bit programmability in normal
mode.
●● Over-temperature protection
●● UVLO protection
●● Green & Pb-free (RoHS compliant) BOM
2.0 Description
The iW7032 is a high efficiency driver for LEDs. It is designed
for use with mid- to large size LCD panels that use arrays
of LEDs as a backlight source. It is able to communicate
with up to two external step-up or step-down PWM DC-DC
converters to drive up to 32 separate strings of multiple
series-connected LEDs.
The iW7032 features dynamic output voltage control, which
automatically chooses the lowest active LED source voltage
to regulate the feedback voltage of a step-up or step-down
converter. Through this function, the iW7032 is able to
dynamically adjust the output voltage of up to two external
step-up or step-down converters to optimize the system
power efficiency.
The iW7032 also provides 32 constant current sinks with
maximum ±2% current matching. The LED PWM dimming
can be adjusted dynamically through a high bandwidth SPI
interface, which provides users flexibility to control the light
intensity of LEDs. In addition, users can provide versatile
configurations of the iW7032 through SPI interface registers.
The iW7032 can maintain very high efficiency even with the
existence of LED channel total forward voltage mismatch,
with the proprietary digital power management and patent
pending adaptive switch mode LED current regulation
technology.
The iW7032 has multiple features to protect the LED
channels from fault conditions, and these protections are
LED PWM cycle-by-cycle based to ensure system reliability
and provide consistent operation.
iW7032 is available in a low-profile, space-saving thermally
enhanced 10mm x 10mm TQFP-EP package.
3.0 Applications
●● Edgelit Local Dimming for LED TV Backlit
●● Direct & Segment-Edge LED Backlit LCDTV
●● LCD Public Information Displays
Rev. 1.3
iW7032
Page 1
1 page  
iW7032
32-Channel LED Driver for LCD Panel Backlighting
6.0 Recommended Operating Conditions
Parameter
VIN supply voltage
LEDn voltage
LEDn current - Local dimming mode
LEDn current - Scanning mode
Min
9
0.5
32
32
Max
28
56
120
192
Units
V
V
mA
mA
7.0 Electrical Characteristics
VIN = 24 V, 0°C ≤ TA ≤ 85°C, unless otherwise specified
Parameter
Symbol Test Conditions
SUPPLY PINS
LDO3 output voltage
LDO5 output voltage
VLDO3
VLDO5
EN = 3.3 V, ILDO3 = 0 mA
EN = 5 V, ILDO5 = 0 mA
Quiescent current
Standby mode, No LED current
IS
Shutdown mode
LDO3 undervoltage lockout
upper threshold
LDO3 undervoltage lockout
lower threshold
LDO5 undervoltage lockout
upper threshold
LDO5 undervoltage lockout
lower threshold
V3 UVLO HIGH Guaranteed by design
V3 UVLO LOW Guaranteed by design
V5 UVLO HIGH Guaranteed by design
V5 UVLO LOW Guaranteed by design
Internal reference voltage
VIN undervoltage lockout
upper threshold
VIN undervoltage lockout
lower threshold
Internal oscillator frequency
Vref
VIN UVLO HIGH
VIN UVLO LOW
fosc
DIGITAL I/O
High level logic threshold
Low level logic threshold
VT(HIGH)
VT(LOW)
Min Typ Max Unit
3.0 3.3 3.6
5.0 5.5 6.5
4 8 12
120 200
V
V
mA
µA
2.7 2.85
V
2.25 2.5
V
4.6 4.75
V
3.8 4.0
1.225 1.25 1.275
8.4 8.5
6.6 7.2
2.33 2.4576 2.58
V
V
V
V
MHz
2.0 V
0.4 V
Rev. 1.3
iW7032
Page 5
5 Page 
iW7032
32-Channel LED Driver for LCD Panel Backlighting
9.2 Calibration
In order to reduce the in rush current, calibration is based
on 5% dimming ratio for scanning mode and 10% dimming
ratio for local dimming mode calibration by default. The
calibration dimming ratio for local dimming can be adjusted
by programming the brightness registers, and the calibration
dimming ratio for scanning mode is always the half dimming
ratio for local dimming. If the dimming ratio for local dimming
is programmed less than 6.25%, then the IC internally clamps
this ratio to be 6.25%. For scanning mode calibration, the
minimum dimming ratio is 3.125%. In addition, the PWM
frequency is based on software programmed value and LED
string turning on sequence is following the dimming group
setting and td_dg registers programmed delay.
Calibration is performed after the SPI initialization is complete
and the Boost/Buck voltage has settled for 20 milliseconds
allowing for the initial ramp up.
Figure 9.6 below describes the sequence used by the
firmware to bring up iW7032 to enable calibration.
Turn on external Boost/Buck converters
Provide Vin power supplies for
IC’s and apply Vsync signal
Turn on IC - s-et EN pin to high
Firmware polls “Init_done”
1
0
Program “One Time” Registers
Figure 9.5 below describes the calibration sequence that is
performed using VDAC, IDAC, and FORCE_ON.
Program “User Mode” Registers
Initialization
System Enable ICs
IC Analog/ Digital
Wakeup
init_done
Software Initializes IC
control registers through SPI
interface
Turn on all channels and
waiting for the first channel
being regulated
Waiting 20ms for Boost/Buck
voltage- settle-down with the SC
mode SIset current
VDAC Calibration for
Scanning Mode
Boost/Buck Voltage Calibration
Switch to LD and turn on valid
channels waiting 20 ms for
Boost/Buck voltage
settling-down
VDAC Calibration for
Local Dimming Mode
Boost/Buck Voltage Calibration
IDAC Calibration
32-LED channel current
measurement
Turn-off all channels and do
the pre-calculation
cali_done
Figure 9.5. Calibration Sequence
Firmware polling “Cali_done”
1
0
Programming “Real Time” registers
based on LD/SC timing diagram
Figure 9.6. Firmware Sequence to Enable iW7032 Calibration
The function of the signals used in calibration are as follows.
VDAC is the digital value (8-bits) that drives the DAC which
is used to affect the feedback input to the external Boost/
Buck controller.
FORCE_ON is an internally generated digital signal from
the LDO regulator that indicates whether or not the LDO
is operating in the specified regulation. If it comes out of
regulation, the FORCE_ON signal goes true.
There are two 8-bit DAC’s used for adjustment of the Boost/
Buck calibration; one for each of the two possible Boost/
Buck groups. The following sequence is performed for each
Boost/Buck group, one group at a time.
The VDAC is in tri-state mode before the software initializes
the IC control register through the SPI interface. Once the
software completes initializing the IC, the VDAC setting is
set to 0 by default which will cause the Boost/Buck regulator
Rev. 1.3
iW7032
Page 11
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet IW7032.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| IW7032 | 32-Channel LED Driver | iWatt |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |