VCC
VREF
ZCDFLT2
DIM GATE
VAC CS
COMP GND
FB ISEN
HOLDVADJ
FLT1
BIAS
9
10
11
12
13
14
15
16
8
7
6
5
4
3
2
1
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LM3450A Pin Descriptions
6 LM3450A Pin Descriptions
Pin Name Description Application Information
Reference Output: Connect directly to VADJ or to resistor
1 VREF 3V Reference divider feeding VADJ and to necessary external circuits.
Analog Dim and Phase Dimming Range Input: Connect
directly to VREF to force standard 70% phase dimming
2 VADJ Analog Adjust range. Connect to resistor divider from VREF to 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
3 FLT2 Filter 2 FLT1 capacitor and a capacitor to GND to establish
second filter pole.
Angle Decoder Output: Connect a series resistor to a
4 FLT1 Filter 1 capacitor to ground to establish first filter pole.
Open Drain PWM Dim Output: Connect to dimming input
5 DIM 500 Hz PWM Output of output stage LED driver (directly or with isolation) to
provide decoded dimming command.
Multiplier and Angle Decoder Input: Connect to resistor
6 VAC Sampled Rectified Line divider from rectified AC line.
Error Amplifier Output and PWM Comparator Input:
7 COMP Compensation Connect a capacitor to GND to set the compensation.
Error Amplifier Inverting Input: Connect to output voltage
via resistor divider to control PFC voltage loop for non-
8 FB Feedback isolated designs. Connect to a 5.11kΩresistor to 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 resistor to GND to sense input
9 ISEN Input Current Sense 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
11 CS Current Sense terminal of sense resistor in PFC MosFET source.
Gate Drive Output: Connect to gate of main power
12 GATE Gate Drive MosFET for PFC.Gate Drive Output: Connect to gate of
main power MosFET for PFC.
Power Supply Input: Connect to primary bias supply.
13 VCC Input Supply Connect a 0.1µF bypass capacitor to ground.
Demagnetization Sense Input: Connect a resistor to
14 ZCD Zero Crossing Detector transformer/inductor winding to detect when all energy
has been transferred.
Open Drain Dynamic Hold Input: Connect to holding
15 HOLD Dynamic Hold resistor which is connected to source of passFET.
5
SNVA485B–June 2011–Revised May 2013 AN-2150 LM3450A Evaluation Board
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