ML4877 Datasheet, PDF (2/11 Pages) Micro Linear Corporation – LCD Desktop Backlight Lamp Driver

ML4877
PIN CONFIGURATION
LEA+
AZR
SS CAP
RT
VREF
L ILIM
LEA–
LEA OUT
CT
L RTD
ML4877
20-Pin SSOP (R20)
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
TOP VIEW
B OFF
B ON
GND
PGND
L GATE 2
ON/OFF
L GATE 1
VDD
HVDD
B SYNC OUT
PIN DESCRIPTION
PIN NAME
FUNCTION
1 LEA+
Positive input for lamp error amp
2 AZR
Connection to gate of external FET for
high voltage regulator. Internally a
zener diode to ground.
3 SS CAP
Connection of optional external soft
start capacitor
4 R_T
5 VREF
Oscillator timing resistor
Voltage reference output
6 L ILIM
Input to current limit amplifier
7 LEA-
Negative input for lamp error
amplifier
8 LEA OUT Output of lamp error amplifier.
External compensation capacitor
connects between this pin and LEA.
9 C_T
10 L RTD
Oscillator timing capacitor
Input to resonant threshold detector
PIN NAME
11 B SYNC
OUT
12 HVDD
13 VDD
14 L GATE1
15 ON/OFF
16 L GATE2
17 PGND
18 GND
19 B ON
20 B OFF
FUNCTION
Output of MOSFET driver to gate of
synchronous FET catch diode.
Battery power input to linear regulator
Output of linear regulator. Positive
power for IC.
Output of MOSFET driver. Connection
to gate of one side of inverter FET
drive pair.
Logic input for chip
Output of MOSFET driver. Connection
to gate of one side of inverter FET
drive pair.
Power ground
Signal ground
Connection to primary side of gate
pulse transformer
Output of MOSFET driver. Connection
to gate of FET that disables the input
power.
2