LM3463_12 Datasheet, PDF (4/40 Pages) Texas Instruments – LM3463 Dynamic Headroom Controller with Thermal Control Interface and Individual Channel Dimming Control

LM3463
SNVS807 – MAY 2012
www.ti.com
Pin Descriptions (continued)
Pin
Name
Description
Application information
Multi-function input pin.
The function of this pin differs depending on the selected operation mode
that sets by the MODE pin.
Direct PWM mode: apply bi-level PWM signal (TTL logic high and low) to
Channel 2/3 PWM dimming control this pin to enable/disable ch2 and ch3. Apply a logic high to this pin to
8
DIM23
enable both channel 2 and 3.
Serial clock input
In serial interface mode, this pin is configured as the serial clock signal
input.
DC voltage dimming control
In DC interface mode, the voltage on this pin is converted into PWM
dimming duty for channel 2 and 3.
Multi-function input pin.
The function of this pin differs depending on the selected operation mode
that sets by the MODE pin.
Channel 4 dimming control
Direct PWM mode: apply bi-level PWM signal to this pin to enable/disable
channel 4. Apply logic high to this pin to enable channel 4.
9
DIM4
Load data control pin
In serial interface mode, this pin is configured as load pulse input, pulling
this pin low will latch the shifted-in data into internal register of the
LM3463. This pin is pulled low if the requested load operation is not
completed. User should check the status of this pin before writing data into
the LM3463 through this pin.
DC voltage dimming control
In DC interface mode, the voltage on this pin is converted into PWM
dimming duty for channel 4.
Multi-function input pin.
The function of this pin differs depending on the selected operation mode
that sets by the MODE pin.
Channel 5 dimming control
10
DIM5
Direct PWM mode: Apply a bi-level PWM signal (TTL logic high and low)
to this pin to enable/disable channel 5. Apply a logic high to this pin to
enable channel 5.
Serial operation mode
This pin should connect to GND when serial operation mode is selected.
DC voltage dimming control
In DC interface mode, the voltage on this pin is converted into PWM
dimming duty for channel 5.
11
SYNC
Serial data output for cascade
operation
Serial control signal output pin for cascade operation. This signal
synchronizes with the rising edge of the CLKOUT signal and carries
information to the slave devices to turn on LEDs.
Sync. pulse input in direct PWM
mode
This is a synchronization signal input pin for the slave device to perform
LED pretest upon system startup.
Dimming clock output for cascade Dimming clock output for cascade operation. The frequency at this pin
12
CLKOUT operation / Sync pulse output for equal to 1/2 of the internal clock or externally applied clock frequency.
Direct PWM mode
13
ISR
Start up current control pin
Connect a resistor from this pin to GND to set the additional bias current
to the C_DHC upon system startup.
The voltage on this pin defines the threshold of the drain voltage of the
external MOSFETs (V_DRn) to begin output current reduction.
14
DRVLIM MOSFET power limit setting input ^{As the V}DRn ^{exceeds V}DRVLIM^{, the LED driving current reduces according}
to the increasing of V_DRn at certain fixed rate. This function prevents the
MOSFET from over-heating. The maximum power dissipation is limited to
V_DRVLIM * I_LED(per ch.).
15
CDHC
Dynamic headroom control time
constant capacitor
Connect a capacitor (C_DHC) from this pin to ground to program the DHC
loop response.
16
FCAP Fault de-bounce capacitor
Connect a capacitor, C_FLT from this pin to ground to program the fault de-
bounce time.
17
GND
System ground
This pin should connect to the system ground
Operation mode selection input pin. Bias this pin externally to set the
LM3463 in different operation mode.
18
MODE Mode select input pin
19
VCC
Internal regulator output
Direct PWM mode: V_MODE = GND
Serial interface mode: V_MODE = No Connection
DC interface mode: V_MODE = VCC
Output terminal of the internal voltage regulator. This pin should be
bypassed to GND through a 1uf ceramic capacitor.
4
Submit Documentation Feedback
Product Folder Links: LM3463
Copyright © 2012, Texas Instruments Incorporated