Datasheet

V
CC
V
REF
ZCDFLT2
DIM GATE
V
AC
CS
COMP GND
FB I
SEN
HOLDV
ADJ
FLT1
BIAS
9
10
11
12
13
14
15
16
8
7
6
5
4
3
2
1
LM3450
SNVS681D –NOVEMBER 2010–REVISED MAY 2013 www.ti.com
Connection Diagram
Top View
Figure 1. 16-Lead TSSOP
Package Number PW
PIN DESCRIPTIONS
Pin Name Description Application Information
Reference Output: Connect directly to V
ADJ
or to resistor divider feeding V
ADJ
1 V
REF
3V Reference
and to necessary external circuits.
Analog Dim and Phase Dimming Range Input: Connect directly to V
REF
to force
standard 70% phase dimming range. Connect to resistor divider from V
REF
to
2 V
ADJ
Analog Adjust
extend usable range of some phase dimmers or for analog dimming. Connect to
GND for low power mode.
Ramp Comparator Input: Connect a series resistor from FLT1 capacitor and a
3 FLT2 Filter 2
capacitor to GND to establish second filter pole.
Angle Decoder Output: Connect a series resistor to a capacitor to GND to
4 FLT1 Filter 1
establish first filter pole.
Open Drain PWM Dim Output: Connect to dimming input of output stage LED
5 DIM 500 Hz PWM Output
driver (directly or with isolation) to provide decoded dimming command.
Multiplier and Angle Decoder Input: Connect to resistor divider from rectified AC
6 V
AC
Sampled Rectified Line
line.
Error Amplifier Output and PWM Comparator Input: Connect a capacitor to GND
7 COMP Compensation
to set the compensation.
Error Amplifier Inverting Input: Connect to output voltage via resistor divider to
control PFC voltage loop for non-isolated designs. Connect a 5.11kΩ resistor to
8 FB Feedback
GND for isolated designs (bypasses error amplifier). Also includes over-voltage
protection and shutdown modes.
Input Current Sense Non-Inverting Input: Connect to diode bridge return and
9 I
SEN
Input Current Sense resistor to GND to sense input current for dynamic hold. Connect a 0.1µF
capacitor and Schottky diode to GND, and a 0.22µF capacitor to HOLD.
10 GND Power Ground System Ground
MosFET Current Sense Input: Connect to positive terminal of sense resistor in
11 CS Current Sense
PFC MosFET source.
12 GATE Gate Drive Gate Drive Output: Connect to gate of main power MosFET for PFC.
Power Supply Input: Connect to primary bias supply. Connect a 0.1µF bypass
13 V
CC
Input Supply
capacitor to ground.
Demagnetization Sense Input: Connect a 100kΩ resistor to transformer/inductor
14 ZCD Zero Crossing Detector
winding to detect when all energy has been transferred.
Open Drain Dynamic Hold Input: Connect to holding resistor which is connected
15 HOLD Dynamic Hold
to source of passFET.
Pre-regulator Gate Bias Output: Connect to gate of passFET and through
16 BIAS Pre-regulator Gate Bias
resistor to rectified AC (drain of passFET) to aid with startup.
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