MAX17061ETI+ Maxim Integrated Products, MAX17061ETI+ Datasheet - Page 12

• Manufacturer Part Number: MAX17061ETI+
• Description: IC LED DRVR WHITE BCKLGT 28-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Backlight, White LEDr

Specifications of MAX17061ETI+

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 8
• Internal Driver: Yes
• Type - Primary: Automotive, Backlight
• Type - Secondary: White LED
• Frequency: 1MHz
• Voltage - Supply: 4.5 V ~ 26 V
• Voltage - Output: 5V
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 30mA
• Internal Switch(s): Yes
• Operating Supply Voltage: 5 V
• Maximum Supply Current: 2 mA
• Maximum Power Dissipation: 1667 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

The MAX17061 includes a 5V linear regulator that pro-
vides the internal bias and gate drive for the step-up
controller. When an external 5V is available, the internal
LDO can be overdriven to decrease power dissipation.
Otherwise, connect the IN pin to an input greater than 5.5V.
The MAX17061’s fixed-frequency, current-mode, step-
up controller automatically chooses the lowest active
FB_ voltage to regulate the output voltage. Specifically,
the difference between the lowest FB_ voltage and the
current-source control signal plus an offset (VSAT) is
integrated at the CCV output. The resulting error signal
is compared to the external switch current plus slope
compensation to determine the switch on-time. As the
load changes, the error amplifier sources or sinks cur-
rent to the CCV output to deliver the required peak-
inductor current. The slope-compensation signal is
added to the current-sense signal to improve stability at
high duty cycles.
8-String White LED Driver with
SMBus for LCD Panel Applications
Figure 1. Typical Operating Circuit
12
______________________________________________________________________________________
Fixed-Frequency Step-Up Controller
464k
PWM
DATA
CLK
1 F
1 F
7V TO 21V
V
IN
0.022 F
5.1k
4.7 F
220pF
0.1 F
V
OSC
ISET
FSET
CCV
PWMI
PWMO
SCL
SDA
GND
V
CC
DD
MAX17061
EP
IN
10 H
L1
PGND1
PGND2
LX1
LX2
FB2
FB3
FB4
FB5
FB6
FB7
FB8
FB1
OV
When the input voltage is close to the output voltage, the
MAX17061 automatically skips pulses to prevent over-
charging the output capacitor. In SKIP mode, the induc-
tor current ramps up for a minimum on-time of
approximately 90ns, and then discharges the stored
energy to the output. The switch remains off until another
pulse is needed to boost the output voltage.
The MAX17061 includes an internal low-dropout linear
regulator (V
ear regulator generates a 5V supply to power internal
PWM controller, control logic, and MOSFET driver. The
V
than or equal to 5.5V, V
and powered from an external 5V supply. There is an
internal diode from V
than V
CC
R2
61.9k
C
D1
2 F
OUT
voltage drops to 4.35V in shutdown. If V
2.21M
V
CC
CC
R1
(see Figure 3).
CC
). When V
Internal 5V Linear Regulator
CC
CC
IN
to IN, so V
UP TO 45V
and IN can be tied together
V
is higher than 5.5V, this lin-
OUT
IN
V
CC
must be greater
and UVLO
IN
is less