LDLL16ENTR datasheet(9/102 Pages) STMICROELECTRONICS

9 / 102 page

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

programmable one.

Moreover, the value programmed in the 8-bit DAC per channels group is stored in the RAM and can be

reconfigured dynamically in bus/normal mode.

3.3

Channel driver drop-out voltage

To guarantee the regulation of the programmed channel current, a minimum output voltage (VOUTx_DROP) across

each current generator must be ensured.

The Table 2 shows the minimum channel VOUTx_DROP at the boundary of the regulation region (output current is

3% less than the target value, output power MOS already in the triode region).

If on one hand a lower than minimum recommended VOUTx_DROP leads to a regulated current lower than the

expected one, a too high VOUTx_DROP implies too high power dissipation.

To guarantee the current regulation while optimizing the power dissipation on each channel, in the case of

maximum current set on one channel and TJ at 125 °C (worst case condition), the minimum output voltage drop

(from device OUTx to device GND) is 1 V. In Figure 5. Output channels voltage drop in function of the output

current and temperature is shown the generic channel drop-out voltage as function of the channel output current

for the 3 main temperature values.

Table 2. Minimum channel drop-out voltage at maximum current vs TJ

TJ [°C]

VOUTx_DROP [V]

125

0.9

-40

0.875

Figure 5. Output channels voltage drop in function of the output current and temperature

3.4

Channel output gradual delay

The LDLL16EN features the output gradual delay, which consists in a gradual turning on of the current

generators. In case of driving several outputs simultaneously, the output gradual delay is applied in order to lower

the current transients and improve device emissions. This feature can be activated – for all the channels - through

one dedicated bit (OUT_DELAY, see the Section 6: FTP and RAM memory mapping).

LDLL16EN

Linear current sinkers

DS14111 - Rev 5

page 9/102

LDLL16ENTR Datasheet(PDF) 9 Page - STMicroelectronics