LM3464, LM3464A
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SNVS652F – APRIL 2010 – REVISED MAY 2013
LED Driver with Dynamic Headroom Control and Thermal Control Interfaces
Check for Samples: LM3464, LM3464A
FEATURES
DESCRIPTION
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The LM3464/64A is a 4-channel high voltage current
regulator that provides a simple solution for LED
lighting applications. The LM3464/64A provides four
individual current regulator channels and works in
conjunction with external N-channel MOSFETs and
sense resistors to give accurate driving current for
every LED string. Additionally, the Dynamic
Headroom Control (DHC) output can be interfaced to
the external power supply to adjust the LED supply
voltage to the lowest level that is adequate to
maintain all the string currents in regulation, yielding
the optimal overall efficiency.
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Wide Input Voltage Range
– 12V-80V (LM3464)
– 12V-95V (LM3464A)
Dynamic Headroom Control Ensures Maximum
Efficiency
4 Output Channels With Individual Current
Regulation
High Channel to Channel Accuracy
Digital PWM/Analog Dimming Control Interface
Resistor Programmable Dimming Frequency
and Minimum Duty Cycle (Analog Dimming
Mode)
Direct Interface to Thermal Sensor
Fault Detection
Over Temperature Protection
Thermal Shutdown
Under Voltage Lockout
Thermal Enhanced TSSOP-28 Package
Digital PWM or analog voltage signals can be used to
control the duty cycle of the all the channels. When
analog control is used, the dimming frequency can be
programmed via an external capacitor. A minimum
duty cycle control is provided in the conditions that
the analog dimming is configured as thermal
feedback.
Protection features include VIN under-voltage lockout, LED open/short circuit and over-temperature fault
signaling to the system controller.
APPLICATIONS
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Streetlights
Solid State Lighting Solutions
Typical Application
High Power LED Arrays
VRAIL
NTC thermistor
couple to LED
arrays
RFB1
Voltage
output
B
EN
OutP
VLedFB
CDHC
Voltage
feedback pin
RFB2
CDHC
VIN
DR1
DR2
DR3
DR4
FAULT_CAP
CFLT
PGND
VDHC
FAULTb
Q2
GD2
SE2
AGND
External voltage headroom control
Q3
GD3
SE3
VDHC
Fault acknowledgement output
Faultb
DIM
Q4
GD4
SE4
RISNS1
RTHM1
PWM dimming input
RISNS2
RISNS3
RISNS4
Thermal
5V
0V
Q1
GD1
SE1
VCC
DIM
To thermal
sensor
terminals
LM3464/64A
RDHC
Primary power
supply
A
PGND
RDMIN1
RTHM2
A
To NTC thermal
sensor
RDMIN2
B
PGND
PGND
PGND
DMIN
CVCC
Thermal_Cap
SYNC
AGND
PGND
AGND
PGND
CTHM
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2010–2013, Texas Instruments Incorporated
LM3464, LM3464A
SNVS652F – APRIL 2010 – REVISED MAY 2013
www.ti.com
Connection Diagram
Figure 1. Top View
28-Lead TSSOP-28
Package Number PWP
PIN DESCRIPTIONS
2
Pin
Name
Description
Application Information
1
SYNC
Synchronization signal output for
cascade operation
(Master-Slave configuration)
Connect this pin to the DIM pin of other LM3464/64A to enable cascade
operation (multiple device). This pin should leave open for single device
operation.
2
DIM
PWM dimming control
Apply logic level PWM signal to this pin controls the average brightness of the
LED string. ( 80V/95V (LM3464/64A)
APPLICATIONS WITH HIGH RAIL VOLTAGE
The normal operation voltage of the LM3464 and LM3464A are rated to 80V and 95V respectively, applying
voltage over the operation voltage limit to the LM3464/64A can damage the device permanently. In applications
that the rail voltage is higher than the operation voltage limited of the device (80V for LM3464, 95V for
LM3464A), voltage clamping circuits must be added externally to ensure the voltage limits of all the pins of the
LM3464/64A are not violated. Figure 26 shows a typical application circuit with 150V peak rail voltage.
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LM3464, LM3464A
SNVS652F – APRIL 2010 – REVISED MAY 2013
www.ti.com
In Figure 26, Z1, Z2, Z3, Z4 and ZIN are zener diodes for clamping the DRx pin voltage and input voltage (VIN pin)
of the LM3464/64A. The reverse voltage of the zener diodes must be below 80V for LM3464 and 95V for
LM3464A. The resistors RDR1, RDR2, RDR3, RDR4 and RIN are resistors for absorbing the voltage difference
between the clamping voltage of the zener diodes and the rail voltage.
Calculating the Values of Zx and RDRx:
The resistance of the RDRx must be properly selected according to the reverse current of the zener diode and
input current of the DRx pins of the LM3464/64A to secure the allowable pin voltages are not violated. For
instant, the DRx pins are required to clamp at 75V and a 500mW/75V zener diode CMHZ5267B from Central
Semiconductor is used. The reverse current of the CMHZ5267B is specified 1.7mA at 75V zener voltage. The
maximum allowable reverse current is 6.67mA as the power rating of the CMHZ5276B is 500mW.
Given that the input current of the DRx pins of the LM3464/64A at 100V is 63uA maximum, if the DRx pin voltage
is below 100V the current flows into the DRx pin (IDRx) is below 63uA. In order to reserve operation margin for
component variations, IDRx is assumed equal to 63uA in the following calculations.
Because VRAIL(peak) is the possible highest voltage at the DRx pins, the maximum resistance of RDRx can be
obtained following this equation:
(22)
Where VZ and IZ are the reverse voltage and current of the zener diode Zx respectively.
For VRAIL(peak) = 150V, the maximum value of RDRx is:
(23)
And the minimum value of RDRx is:
(24)
Thus, the value of RDRx must be selected in the range:
(25)
To minimize power dissipation on the zener diodes, a standard 42.2kΩ resistor can be used for the RDRx.
Because the resistors, RDRx are used to absorb the power being introduced by the voltage difference between
VRAIL and VZx, the maximum power dissipation on every RDRx equals to:
(26)
Thus, a standard 42.2kΩ resistor with 0.25W power rating (1206 package) and 1% tolerance can be used.
Calculating the Values of ZIN and RIN:
Similar to the requirements of selecting the Zx and RDRx, the voltage at the VIN pin of the LM3464/64A is
clamped to 75V by a voltage clamping circuit consists of ZIN and RIN. Because the maximum operating and shutdown current (VEN < 2.1V) are 3mA and 700uA respectively, in order to ensure the voltage of the VIN pin is
clamped close to 75V even when the LM3464/64A is disabled, a 1.5W/75V zener diode CMZ5946B from Central
Semiconductor is used to ensure adequate conduction current for ZIN. The reverse current of the CMZ5946B is
specified 5mA at 75V, so the allowable current flows through ZIN is in between 5mA to 20mA.
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LM3464, LM3464A
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SNVS652F – APRIL 2010 – REVISED MAY 2013
The value of RIN is governed by the following equations:
(27)
Maximum value of RIN:
(28)
Minimum value of RIN:
(29)
So the value of RIN must be in the range:
(30)
To minimize power dissipations on both the ZIN and RIN, a standard 9.31kΩ resistor can be selected for the RIN.
Then the maximum power dissipation on RIN is:
(31)
Thus, a standard 9.38kΩ resistor with 2512 package (1W) and 1% tolerance can be used.
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LM3464, LM3464A
SNVS652F – APRIL 2010 – REVISED MAY 2013
www.ti.com
Additional Application Circuit
Figure 27. Cascade Operation with Thermal Foldback Control
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Product Folder Links: LM3464 LM3464A
LM3464, LM3464A
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SNVS652F – APRIL 2010 – REVISED MAY 2013
REVISION HISTORY
Changes from Revision E (May 2013) to Revision F
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Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 24
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM3464AMH/NOPB
ACTIVE
HTSSOP
PWP
28
48
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LM3464AMH
LM3464AMHX/NOPB
ACTIVE
HTSSOP
PWP
28
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LM3464AMH
LM3464MH/NOPB
ACTIVE
HTSSOP
PWP
28
48
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LM3464MH
LM3464MHX/NOPB
ACTIVE
HTSSOP
PWP
28
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LM3464MH
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of