MSL3162BT-R Atmel, MSL3162BT-R Datasheet - Page 14

• Manufacturer Part Number: MSL3162BT-R
• Description: LED Lighting Drivers 16String RGB & White LED Drivers with A
• Manufacturer: Atmel

Specifications of MSL3162BT-R

• Rohs: yes
• Input Voltage: 4.5 V to 5.5 V
• Maximum Supply Current: 20 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TQFN-40
• Minimum Operating Temperature: - 40 C
• Power Dissipation: 2.1 W
• Factory Pack Quantity: 2500

Detailed Description
Internal Regulators and Enable Input
Built-in current control MOSFETs capable of withstanding
up to 40V provide a compact solution. The Efficiency
Optimizer circuit controls the LED voltage generated
by an external DC-DC converter to minimize losses on
the current control MOSFETs, improving efficiency and
reducing driver power dissipation. The MSL3162 uses
a high-speed, 1MHz I
current, PWM dimming, and fault detection circuitry,
making it an optimal solution for driving LED backlights
for LCD panels. Onboard EEPROM allows default settings
to be reconfigured for customization and settings to be
saved at turn-off, eliminating the need to re-write settings
at the next turn-on. The tiny, 6mm x 6mm QFN package
enables a compact solution while maintaining high power
dissipation.
Internal Regulators and Enable Input
The MSL3162 includes an internal linear regulator that
provides 2.5V supply voltage to power internal circuitry.
Bypass VDD to GND with a 1µF or greater capacitor as close
to the MSL3162 as possible.
The EN input turns the MSL3162 on and off. To turn
on the MSL3162, drive EN high with a 5V logic level,
and drive EN low to turn it off. When EN is low, the
MSL3162 enters low-power mode, reducing input
current to 20µA, and turns off the serial interface. For
automatic start-up, connect EN to VIN, allowing the
MSL3162 to start automatically when voltage is applied.
LED String Current Control
Each MSL3162 includes 16 current sink outputs, rated
at 40V, each capable of sinking up to 100mA through a
string of series connected LEDs. The internal Efficiency
Optimizer circuit controls the LED voltage, minimizing
power dissipated in the current sinks while maintaining
high current-regulation accuracy. The MSL3162 power
dissipation is limited to 2.1W. When using all 16 current
sinks, maintain the total power dissipation within power
dissipation limits.
14
2
C serial interface to control LED
Setting the Maximum LED String Current
The maximum I
to STR15 is set by external resistor R
pin to GND and is determined by the equation:
where I
R
R
the maximum allowed. The currents for the 16 LED
strings, STR0 to STR15, are reduced individually from
full scale with 6-bit resolution using the LED string
current control registers.
If I
to be 30mA or lower (by selecting the value of external
resistor R
values programmed into the LED string current control
registers must be limited to the range 0x00 to 0x1F.
The full range of 0x00 to 0x3F is only available if I
set to be greater than 30mA by using an R
68.3kΩ or lower.
I
ILED
ILED
ILED
ILED
=34.8kΩ sets the full-scale LED current to 58.9mA.
=20.5kΩ sets the full-scale LED current to 100mA,
for the 16 LED strings, STR0 to STR15, is chosen
=
ILED
ILED
2050
R
is in mA and R
ILED
to be greater than 68.3kΩ), then the
ILED
current for the 16 LED strings STR0
ILED
is in kΩ.
Atmel LED Driver-MSL3162
ILED
from the ILED
ILED
value of
ILED
is