User manual

1
4
3
2
10
7
8
9
I
SNS
FLTR1
GATE
BLDR
COFF
V
CC
ASNS
DIM
5 6FLTR2 GND
www.ti.com LM3445 Device Pin-Out
6 LM3445 Device Pin-Out
Figure 4. LM3445 Device Pin-Out
Table 1. Pin Description 10 Pin VSSOP
Pin # Name Description
1 ASNS PWM output of the TRIAC dimmer decoder circuit. Outputs a 0 to 4V PWM signal with a duty cycle proportional
to the TRIAC dimmer on-time.
2 FLTR1 First filter input. The 120Hz PWM signal from ASNS is filtered to a DC signal and compared to a 1 to 3V, 5.85
kHz ramp to generate a higher frequency PWM signal with a duty cycle proportional to the TRIAC dimmer firing
angle. Pull above 4.9V (typical) to tri-state DIM.
3 DIM Input/output dual function dim pin. This pin can be driven with an external PWM signal to dim the LEDs. It may
also be used as an output signal and connected to the DIM pin of other LM3445 or LED drivers to dim multiple
LED circuits simultaneously.
4 COFF OFF time setting pin. A user set current and capacitor connected from the output to this pin sets the constant
OFF time of the switching controller.
5 FLTR2 Second filter input. A capacitor tied to this pin filters the PWM dimming signal to supply a DC voltage to control
the LED current. Could also be used as an analog dimming input.
6 GND Circuit ground connection.
7 ISNS LED current sense pin. Connect a resistor from main switching MOSFET source, ISNS to GND to set the
maximum LED current.
8 GATE Power MOSFET driver pin. This output provides the gate drive for the power switching MOSFET of the buck
controller.
9 V
CC
Input voltage pin. This pin provides the power for the internal control circuitry and gate driver.
10 BLDR Bleeder pin. Provides the input signal to the angle detect circuitry as well as a current path through a switched
230Ω resistor to ensure proper firing of the TRIAC dimmer.
7 Bill of Materials
Designator Description Manufacturer Part Number
AA1 Printed Circuit Board - 551600457-001A
C1 CAP .047UF 630V METAL POLYPRO EPCOS Inc B32559C6473K000
C2 CAP 10000PF X7R 250VAC X2 2220 Murata Electronics North America GA355DR7GB103KY02L
C3, C4 CAP 330UF 35V ELECT PW Nichicon UPW1V331MPD6
C5 CAP CER .33UF 250V X7R 1812 TDK Corporation C4532X7R2E334K
C6 CAP .10UF 305VAC EMI SUPPRESSION EPCOS B32921C3104M
C7 CAP, CERM, 0.1µF, 16V, +/-10%, X7R, Kemet C0805C104K4RACTU
0805
C8 CAP CER 47UF 16V X5R 1210 MuRata GRM32ER61C476ME15L
C9 CAP CER .10UF 250V X7R 10% 1206 TDK C3216X7R2E104K
C10 CAP CER .22UF 16V X7R 0603 MuRata GRM188R71C224KA01D
C11 CAP CER 2200PF 50V 10% X7R 0603 MuRata GRM188R71H222KA01D
C12 CAP CER 330PF 50V 5% C0G 0603 MuRata GRM1885C1H331JA01D
7
SNVA429C–August 2010–Revised May 2013 AN-2034 LM3445 -120VAC, 8W Isolated Flyback LED Driver
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