MSL3162BT-R Atmel, MSL3162BT-R Datasheet - Page 15

• 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

Efficiency Optimizer
The Efficiency Optimizer improves power efficiency by adjusting each external LED power supply output voltage to the
minimum required by the connected LED strings. It does this by injecting a current from the FBO output into the external
LED power source voltage divider (Figure 5), thus lowering the LED supply voltage. The power supply's feedback
voltage (internal reference voltage) must be 1.4V or less, and the voltage setting feedback network divider must be
accessible. Use a Schottky diode (CMPSH-3 or similar) as shown to protect the power source against reverse current
flow into the FBO pin, should the power supply circuit be powered before the MSL3162.
Connecting an LED String Power Supply to an Efficiency Optimizer
An LED string power supply uses a voltage divider (R
output voltage is set by the voltage divider ratio and the power supply feedback regulation voltage per the equation:
V
the 40V maximum rating of the MSL3162’s LED string outputs, STR0 to STR15.
The Efficiency Optimizer modifies the feedback network by injecting a current, I
FBO output into the measurement node, FB. The minimum power supply output voltage is determined by the equation:
where I
From these equations, the equations to calculate the feedback resistors are:
Atmel LED Driver-MSL3162
V
V
R
OUT(MAX)
FB
OUT
TOP
=
(
MIN
=
V
FBOx(MAX)
V
OUT
must exceed the maximum LED string voltage to ensure regulation, but ensure that V
)
FB
=
(
*
MAX
V
V
OUT
is the 45µA maximum output current from the Efficiency Optimizer output.
MAX
I
)
FBO
*
(
MAX
R
−
(
TOP
MAX
V
)
R
MIN
−
BOTTOM
+
)
(
R
I
F
BOTTOM
BOx
(
MAX
and
)
*
R
TOP
or
)
R
BOTTOM
V
16-string, RGB and White LED Drivers with Adaptive
TOP
OUT
Power Control and 1MHz I
Figure 5. Atmel LED Driver-MSL3162
FBO_Connection to Power Supply Voltage Divider
and R
(
MAX
=
R
)
TOP
BOTTOM
=
Atmel LED Driver-MSL3162
V
*
FB
V
in Figure 6) to set its output voltage. The maximum
OUT
*
V
R
FB
−
TOP
V
R
FB
+
BOTTOM
FBO
R
, in the range of 0 to 45µA from the
BOTTOM
2
C/SMBus Serial Interface
OUT(MAX)
is always under
15