Texas Instruments 4 Channel LED Driver Evaluation Board LM3464EVAL/NOPB LM3464EVAL/NOPB 데이터 시트
제품 코드
LM3464EVAL/NOPB
LM3464A 4 Channel LED
Driver Evaluation Board
Driver Evaluation Board
National Semiconductor
Application Note 2071
SH Wong
June 3, 2011
Application Note 2071
SH Wong
June 3, 2011
Introduction
This evaluation board demonstrates the high power efficiency
and outstanding output current accuracy of the LM3464A typ-
ical application circuit. With four LED strings connected, the
total output power is about 50W. The schematic, bill of mate-
rial and PCB layout drawing of the LM3464A evaluation board
are provided in this document. This evaluation board can be
adapted to different types of power supply with changes of a
few components. The PCB of this evaluation board is pin to
pin compatible to both LM3464 and LM3464A with 80V and
95V maximum input voltage respectively. The information be-
ing presented in this document are also applicable to both the
LM3464 and LM3464A.
The LM3464A is a 4 channel linear LED driver which com-
bined the advantages of high power efficiency of switching
regulators and low current ripple of linear current regulators.
With the incorporation of the proprietary Dynamic Headroom
Control (DHC) technology, the LM3464A optimizes system
efficiency automatically while providing outstanding output
stability and accuracy. Each LED current regulators of this
board consists of an external MOSFET and a control circuit
inside the LM3464A to provide the best flexibility to fulfill the
needs of different applications. The LM3464A includes a built-
in Low Drop-Out (LDO) voltage regulator which accepts an
input voltage up to 95V (LM3464A) to provide power and volt-
age references to internal circuits, allowing the LM3464A to
adapt to difference source voltages easily. The integrated
thermal foldback control circuit protects the LED Strings from
damages due to over-temperature. This eventually secures
the lifetime of the entire lighting system. The LM3464A in-
cludes a fault handling mechanism which latches off output
channels upon open or short circuit of the LED strings, pre-
venting substantial damages due to failures of the LEDs. The
number of output channel can be expanded by cascading
several LM3464A evaluation boards to achieve high luminous
output.
and outstanding output current accuracy of the LM3464A typ-
ical application circuit. With four LED strings connected, the
total output power is about 50W. The schematic, bill of mate-
rial and PCB layout drawing of the LM3464A evaluation board
are provided in this document. This evaluation board can be
adapted to different types of power supply with changes of a
few components. The PCB of this evaluation board is pin to
pin compatible to both LM3464 and LM3464A with 80V and
95V maximum input voltage respectively. The information be-
ing presented in this document are also applicable to both the
LM3464 and LM3464A.
The LM3464A is a 4 channel linear LED driver which com-
bined the advantages of high power efficiency of switching
regulators and low current ripple of linear current regulators.
With the incorporation of the proprietary Dynamic Headroom
Control (DHC) technology, the LM3464A optimizes system
efficiency automatically while providing outstanding output
stability and accuracy. Each LED current regulators of this
board consists of an external MOSFET and a control circuit
inside the LM3464A to provide the best flexibility to fulfill the
needs of different applications. The LM3464A includes a built-
in Low Drop-Out (LDO) voltage regulator which accepts an
input voltage up to 95V (LM3464A) to provide power and volt-
age references to internal circuits, allowing the LM3464A to
adapt to difference source voltages easily. The integrated
thermal foldback control circuit protects the LED Strings from
damages due to over-temperature. This eventually secures
the lifetime of the entire lighting system. The LM3464A in-
cludes a fault handling mechanism which latches off output
channels upon open or short circuit of the LED strings, pre-
venting substantial damages due to failures of the LEDs. The
number of output channel can be expanded by cascading
several LM3464A evaluation boards to achieve high luminous
output.
Standard Settings of the Evaluation
Board
Board
• Vin range 12V to 95V (LM3464A)
• 48V LED turn ON voltage
• 350mA LED current per channel
• 2kHz thermal foldback dimming frequency
Because the LM3464A evaluation board is designed to turn
on the LED strings at 48V rail voltage, applying excessive in-
put voltage to this board will increase power dissipation on the
MOSFETs and could eventually damage the circuit. In order
to avoid permanent damages, it is not recommended not to
apply higher than 60V input voltage to this evaluation board.
This board is generally designed to drive 4 LED strings at
350mA which each sting contains 12 serial LEDs. For driving
LED strings of different configuration, the value of a few com-
ponents should be adjusted following the descriptions in this
document.
• 48V LED turn ON voltage
• 350mA LED current per channel
• 2kHz thermal foldback dimming frequency
Because the LM3464A evaluation board is designed to turn
on the LED strings at 48V rail voltage, applying excessive in-
put voltage to this board will increase power dissipation on the
MOSFETs and could eventually damage the circuit. In order
to avoid permanent damages, it is not recommended not to
apply higher than 60V input voltage to this evaluation board.
This board is generally designed to drive 4 LED strings at
350mA which each sting contains 12 serial LEDs. For driving
LED strings of different configuration, the value of a few com-
ponents should be adjusted following the descriptions in this
document.
Highlight Features
• Dynamic Headroom Control (DHC)
• Thermal foldback control
• High speed PWM dimming
• Minimum brightness limit for thermal foldback control
• Cascade operation for output channel expansion
• Vin Under-Voltage-Lockout
• Fault protection and indication
• Programmable startup voltage
• Thermal Shutdown
• Thermal foldback control
• High speed PWM dimming
• Minimum brightness limit for thermal foldback control
• Cascade operation for output channel expansion
• Vin Under-Voltage-Lockout
• Fault protection and indication
• Programmable startup voltage
• Thermal Shutdown
© 2011 National Semiconductor Corporation
301271
www.national.com
LM3464A 4 Channel LED Driver Evaluation Board
AN-2071