MSL2042GU Atmel, MSL2042GU Datasheet - Page 13

• Manufacturer Part Number: MSL2042GU
• Description: LED Lighting Drivers 4Str RGB or White LED Driver lighting
• Manufacturer: Atmel

Specifications of MSL2042GU

• Rohs: yes
• Input Voltage: 10.8 V to 13.2 V
• Maximum Supply Current: 31.5 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOP-32
• Minimum Operating Temperature: - 40 C
• Power Dissipation: 1576 mW
• Factory Pack Quantity: 1000

but because LEDs differ, the number of shorted LEDs
required to generate a fault varies. The current fold-back
option, available through the serial interface, slightly
changes the fault response when an LED short circuit
event is suspected.
A string with an open circuit LED is off by default, and
when this situation is verified the faulty string is disabled
and no longer monitored by the Efficiency Optimizer.
Toggling EN low and then high clears all faults and the
MSL2041/2 begin to control and monitor all strings as
if experiencing an initial power-up. Fault conditions that
persist re-establish fault responses.
Faulty strings are flagged in the fault registers. When
using the serial interface, fault conditions are typically
read in response to FLTB pulling low.
Figure 3. Open-circuit and Short-circuit Detection Block Diagram
Atmel LED Drivers-MSL2041/2042
Figure 3. Open-Circuit and Short-Circuit Detection Block Diagram
Low-cost, Simple 4-string LED Drivers with External Current Sink
Atmel LED Drivers-MSL2041/MSL2042
MOSFETs, 5000:1 Dimming Range and Per String PWM Input
Over Temperature Shutdown
The MSL2041/2 includes an automatic over-
temperature shutdown. If the die temperature exceeds
135°C, the device turns off, just as if the enable input
EN is forced low. When the die temperature drops
below 120°C the device wakes up again and turns on
as if experiencing an initial power-up.
Connecting the Efficiency Optimizer to an LED
String Power Supply and Selecting Resistors
The MSL2041/2 are designed to control LED string
power supplies that use a voltage divider (R
R
regulation feedback voltage is not more than 3.5V - V
The Efficiency Optimizer improves power efficiency
by injecting a current of between 0µA and 280.5µA
into the voltage divider of the external power supply,
dynamically adjusting the power supply’s output to the
minimum voltage required by the LED strings.
Each of the two EOs monitors two LED strings. Strings
zero and one are assigned to FBO1, and strings two and
three are assigned to FBO2 (Table 1). When a single
supply is used for all four strings connect FBO2 to FBI1
(Figure 4), as explained in the next section “Using
Multiple EOs/Devices to Control a Common Power
Supply”. The MSL2041/2 then automatically maximizes
efficiency for all strings. When two supplies are used,
connect FBO1 to the supply powering strings zero and
one, and connect FBO2 to the supply powering strings
two and three (Figure 5). For clarity, Figure 4 and
Figure 5 do not show the Source and Drain connections
between the devices and the MOSFETs.
BOTTOM
in Figure 4) to set output voltage, and whose
TOP
and
F
.
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