Texas Instruments LM3444 Buck-Boost Topology MR16 LED Bulb Reference Design LM3444MR16BBRB/NOPB LM3444MR16BBRB/NOPB 데이터 시트
제품 코드
LM3444MR16BBRB/NOPB
LM3444-MR16-Boost Reference Design
NATIONAL SEMICONDUCTOR
Page 7 of 20
LM3444 Boost MR16 Reference Design
This reference design was based on the released LM3444 IC from National Semiconductor.
This design was developed to minimize the current spikes coming out of an electronic transformer to less than 5A,
which is a typical transformer rating, when driving an LED MR16 circuit. The off the shelf LED MR16 solutions
exhibit spikes that significantly exceed a transformer’s maximum rated output current which will degrade the
reliability of the transformer and reduce its operating lifetime.
This design generates a continuous LED current when a 220uF 35V electrolytic capacitor is placed across the
output. The circuit operates in a constant output power mode. The output power is fixed at about 6W.
This design was developed to minimize the current spikes coming out of an electronic transformer to less than 5A,
which is a typical transformer rating, when driving an LED MR16 circuit. The off the shelf LED MR16 solutions
exhibit spikes that significantly exceed a transformer’s maximum rated output current which will degrade the
reliability of the transformer and reduce its operating lifetime.
This design generates a continuous LED current when a 220uF 35V electrolytic capacitor is placed across the
output. The circuit operates in a constant output power mode. The output power is fixed at about 6W.
Operating Specifications
NOTE: The following specifications are typical values based on the LED driver being powered directly by a 12VAC
supply (i.e. no electronic or magnetic step-down transformer).
Input Voltage, V
supply (i.e. no electronic or magnetic step-down transformer).
Input Voltage, V
IN
: ............................................................................................................................................. 12 VAC
Output Voltage, V
OUT
: ................................................................................................... 23.5V (Single string of 7 LEDs)
Input Current, I
IN
.................................................................................................................................................. 710mA
LED Output Current, I
LED
..................................................................................................................................... 280mA
Input Power, P
IN
.................................................................................................................................................. ~ 8.0W
Output Power, P
OUT
............................................................................................................................................. ~ 6.6W
Efficiency ............................................................................................................................................................. ~ 83 %
Power Factor ........................................................................................................................................................ ~ 0.95
Power Factor ........................................................................................................................................................ ~ 0.95
Input Voltage, V
IN
: ............................................................................................................................................. 12 VAC
Output Voltage, V
OUT
: ................................................................................................... 26.6V (Single string of 8 LEDs)
Input Current, I
IN
.................................................................................................................................................. 680mA
LED Output Current, I
LED
..................................................................................................................................... 240mA
Input Power, P
IN
.................................................................................................................................................. ~ 7.7W
Output Power, P
OUT
............................................................................................................................................. ~ 6.4W
Efficiency ............................................................................................................................................................. ~ 83 %
Power Factor ........................................................................................................................................................ ~ 0.95
Power Factor ........................................................................................................................................................ ~ 0.95
Input Voltage, V
IN
: ............................................................................................................................................. 12 VAC
Output Voltage, V
OUT
: ................................................................................................... 28.2V (Single string of 9 LEDs)
Input Current, I
IN
.................................................................................................................................................. 670mA
LED Output Current, I
LED
..................................................................................................................................... 220mA
Input Power, P
IN
.................................................................................................................................................. ~ 7.5W
Output Power, P
OUT
............................................................................................................................................. ~ 6.2W
Efficiency ............................................................................................................................................................. ~ 83 %
Power Factor ........................................................................................................................................................ ~ 0.95
SMPS Topology .................................................................................................................................................... Boost
Power Factor ........................................................................................................................................................ ~ 0.95
SMPS Topology .................................................................................................................................................... Boost