ST L99LD01 User Manual

Features
L99LD01
High efficiency constant current LED driver
Data brief
Max V
BATT
Operation supply battery voltage V
BATT
Oscillator frequency range 100 - 500 KHz
Constant current operation
40 V
5.6 - 24 V
resistor and adjustable via SPI
Converter switching frequency adjustable by
external resistor (R
EMC reduction by internal spread spectrum
SF
)
dither oscillator
Low frequency PWM dimming operation
Maximum input current limiter
Maximum switching duty cycle limiter
Slope compensation adjustable by external
resistor (R9)
Battery over voltage shut down protection (ext.
R3,R4 resistors required)
Led chain OV detection (ext. R5, R6)
Multiplexed output for monitoring and control of
LED temperature (external NTC resistor required), voltage of LED chain, and low frequency PWM
SPI communication serial interface transceiver
(SDI, SDO, SCK, CSN)
Parameter programming and settings of
internal memory registers by the dedicated SPI interface:
– LED current reference adjusting (± 66.7 %) – Maximum input current limiter reference
adjusting (± 55.5 %)
– Random dither frequency sweeping,
modulation frequency and deviation percentage
LQFP32 7x7mm
Regulated output for micro supply
5V±2%-20mA
Power on reset pin output
ESD protection
Applications
Automotive day time running light, LED headlamps.
Description
L99LD01 is a complete constant current DC-DC converter LED driver, manufactured in a BCD5S 70 V technology and assembled in a LQFP32 package.
The device is designed to be used in boost, buck­boost and fly back converter topologies. An internal random dither oscillator works in low frequency modulation, allowing spreading the RF spectrum of the switching frequency, so reducing EMC emissions. The slope compensation ensures good converter loop stability whatever is the duty cycle needed by the application.
The converter is able to work either in full power mode or in low frequency dimming mode.
The device includes an internal low drop voltage regulator, that can be used to supply a microcontroller, and a reset pin, that is useful for resetting the microcontroller at the start up and every time that the regulated output voltage falls down below an established voltage threshold.
TM
February 2011 Doc ID 18451 Rev 1 1/3
For further information contact your local STMicroelectronics sales office.
www.st.com
1
Revision history L99LD01
1 Revision history

Table 1. Document revision history

Date Revision Changes
04-Feb-2011 1 Initial release.
2/3 Doc ID 18451 Rev 1
L99LD01
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Doc ID 18451 Rev 1 3/3
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