MAX17061ETI+ Maxim Integrated Products, MAX17061ETI+ Datasheet - Page 16

• 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

8-String White LED Driver with
SMBus for LCD Panel Applications
The full-scale LED current in the DPWM dimming is
determined by resistance from the ISET pin to ground:
The acceptable resistance range is 133kΩ < R
266kΩ, which corresponds to full-scale LED current of
30mA > I
default full-scale LED current of 25mA.
The current source output is pulse-width modulated
and synchronized with a DPWM signal to reduce jitter
and flicker noise in the display.
The MAX17061 uses an internal DPWM signal to perform
dimming control. The DPWM frequency is specified by
an external resistor connected from FSET pin to GND:
where:
The adjustable range for the FSET resistor, R
from 42kΩ to 464kΩ, corresponding to the DPWM fre-
quency of 200Hz to 2kHz.
Figure 4. LED Current Control by DPWM Signal in Dimming
16
D =
I
I
0A
DPWM
LEDMAX
LED
______________________________________________________________________________________
t
DPWM
t
ON
= 58509
= 10.638
LEDMAX
D = 50%
t
DPWM
t
ON
I
LEDMAX
f
DPWM
> 15mA. Connect ISET to V
20
in DPWM Dimming Control
Full-Scale LED Brightness
DPWM Frequency Setting
mA
R
R
10
[ ]
ISET
9
200
k
D = 30%
CC
FSET
ISET
DPWM DIMMING MODE
for a
, is
<
The MAX17061’s dimming control circuit consists of
two interfaces: PWM and SMBus. The block diagram of
these two input interfaces is shown in Figure 5. The
dimming can be performed in three modes: PWM,
SMBus, or DPST. In PWM mode, the brightness is
adjusted by the PWM signal applied to the PWMI pin. In
SMBus mode, the brightness is adjusted by an I
command from uplink processor through the 2-wire
SMBus. In DPST mode, the brightness is adjusted by
the product of the PWM duty cycle and SMBus com-
mand value. This DPWM control provides a dimming
range with 8-bit resolution down to 2.7% and supports
Intel DPST to maximize battery life.
Figure 5. MAX17061 PWM and SMBus Interface Circuit
PWMI
PWMO
SDA
SCL
D = 12.5%
SMBus AND PWM INPUT BLOCK
IDENTIFICATION
0x03
REGISTER
BUFFER
FAULT/STATUS
0x02
REGISTER
A
D
< = 1
Dimming Control Interfaces
PWM_MD
1
INTERFACE
SMBus
MUX
0x01
CONTROL
REGISTER
DEVICE
D = 6.25%
MULTIPLIER
DIGITAL
PWM_SEL
0x00
BRIGHTNESS
MUX
CONTROL
REGISTER
BACKLIGHT
ON/OFF
SETTING
DPWM
2
C