LDLL16ENTR datasheet(8/102 Pages) STMICROELECTRONICS

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Linear current sinkers

3.1

General description

The LDLL16EN features 16 low-side linear current generators to regulate from 6.3 mA to 100 mA current on the

output LED strings.

The output channels can be put in parallel to address all those light functions needing higher current than the

programmable one.

In this device, the current can be individually programmed per channel by using an integrated 8-bit DAC. The

output channels paralleling is allowed, provided that all these channels are controlled simultaneously.

Supplied directly from car battery, the LDLL16EN IC guarantees up to 20 V output driving capability, allowing

users to connect several LEDs in series.

Each LED string can be supplied by battery or through one external pre-regulator connected between battery and

LED string anodes.

The pre-regulated (VPREG) and battery (VS) voltages are internally monitored by an 8-bit ADC, the results are

stored in a dedicated result register. The ADC is used also to monitor the device temperature (TJ) as well as all

the output channels. These channels are refreshed once per PWM period in on-state. The minimum PWM on-

time (vs PWM frequency), to ensure a correct channel ADC reading, is tPWM_ON_OFF time (see the Table 63). In

any case, ADC will not perform any reading operation before a configurable blanking time (tDIAG_BLANK_GROUP_X,

see the Table 65) is elapsed. This blanking time is applied on the first channel turn on as well as on each PWM

rising edge.

The ADC monitoring of all these parameters allows a complete diagnostic: open-load, output channel short to

external pre-regulator, output channel LED (single or multiple) short detection, LED current derating in case of

device temperature increasing.

The LDLL16EN features an 8-bit logarithmic PWM for dimming control to adjust separately the brightness for

each channel. A linear 8-bit global dimming dedicated for each function group mapped with Direct Input pin can

be superimposed with the channel individual dimming.

A slow turn-on and turn-off time (tSR_ON and tSR_OFF) of the channel improves the system low noise generation

performances. Moreover, this device features the output gradual delay (tGD) which avoids contemporary turning

on of all the channels used for a specific light function, reducing the inrush current.

To further improve EMI performances, the device implements an internal clock dithering to have a spread

spectrum noise reduction.

The LDLL16EN integrates a thermal sensor block used to sense the device junction temperature (TJ) as well as to

detect thermal warning (TW) and thermal shutdown (TSD) thresholds, granting device protection in case of

temperature increasing.

The sensed junction temperature (TJ) is monitored by an 8-bit ADC with the aim of starting an automatic,

downwards derating of the LED string current as soon as the TW threshold is reached. The derating ends when

the value (I_PROG-Imin)/2+Imin of LED current is reached, which corresponds to TJ = 165 °C.

The 8-bit ADC is also used to monitor the voltage on the NTC pin, where an external resistor can be connected. If

the monitored voltage, whose value depends on the temperature detected by the NTC resistor itself, reaches the

VNTC_TH threshold (programmable by 3 bits, see the Table 64), a downwards derating of the LED string current

automatically starts, till a fraction of the nominal LED current is reached , this LED current end value is calculated

as (I_PROG-Imin)/2+Imin. This corresponds to a NTC temperature 20 °C higher than VNTC_TH.

The monitoring of both TJ and NTC voltage is contemporary active.

The device can be controlled by microcontroller via CAN FD light compatible interface. Stand-alone operation (no

microcontroller used) is also possible thanks to direct drive functionality and full configurability by FTP. This latter

can be programmed (up to NFTP cycles) in application via CAN FD light compatible interface. Moreover, there is

the possibility to lock any FTP area to avoid unintentional writing.

3.2

Channel current setting

The LDLL16EN features 16 low-side linear current generators to regulate from 6.3 mA to 100 mA current on the

output LED strings. The current can be individually programmed per channel through 8-bit DAC per channel

(setting CUR_SET_CHx bits, see the Section 6: FTP and RAM memory mapping).

LDLL16EN

Linear current sinkers

DS14111 - Rev 5

page 8/102

LDLL16ENTR Datasheet(PDF) 8 Page - STMicroelectronics

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