Pin description (continued) – Rainbow Electronics MAX17127 User Manual
Page 10
10 _____________________________________________________________________________________
MAX17127
Six-String WLED Driver with Integrated
Step-Up Converter
Pin Description (continued)
PIN
NAME
FUNCTION
7
FB5
LED String 5 Cathode Connection. FB5 is the open-drain output of an internal regulator, which
controls current through FB5. FB5 can sink up to 30mA. If unused, connect FB5 to AGND.
8
FB4
LED String 4 Cathode Connection. FB4 is the open-drain output of an internal regulator, which
controls current through FB4. FB4 can sink up to 30mA. If unused, connect FB4 to AGND.
9
AGND
Analog Ground
10
FB3
LED String 3 Cathode Connection. FB3 is the open-drain output of an internal regulator, which
controls current through FB3. FB3 can sink up to 30mA. If unused, connect FB3 to AGND.
11
FB2
LED String 2 Cathode Connection. FB2 is the open-drain output of an internal regulator, which
controls current through FB2. FB2 can sink up to 30mA. If unused, connect FB2 to AGND.
12
FB1
LED String 1 Cathode Connection. FB1 is the open-drain output of an internal regulator, which
controls current through FB1. FB1 can sink up to 30mA. If unused, connect FB1 to AGND.
13
R_FPWM
Connect R_FPWM to AGND
14
OVP
Overvoltage Sense. Connect OVP to the boost converter output through a resistor:
V
OVP
= 1.25V O (1 + R
1
/R
2
)
15
PGND
Boost Regulator Power Ground
16
SW
Boost Regulator Power Switch Node
17
I.C.
Internal Connection. Not connected externally.
18
COMP
Step-Up Converter Compensation Pin. Connect a ceramic capacitor in series with a resistor from
COMP to AGND.
19
V
IN
Supply Input. V
IN
biases the internal 5V linear regulator that powers the device. Bypass V
IN
to
AGND directly at the pin with a 0.1FF or greater ceramic capacitor.
20
PWM
PWM Signal Input. This signal is used for brightness control. The brightness is proportional to the
PWM duty cycle, and the PWM signal directly controls the LED turning on/off.
—
EP
Exposed Backside Pad. Solder to the circuit board ground plane with sufficient copper connection
to ensure low thermal resistance. See the PCB Layout Guidelines section.