STLD20CP1PQR STMicroelectronics, STLD20CP1PQR Datasheet - Page 11

• Manufacturer Part Number: STLD20CP1PQR
• Description: IC LED DRIVR BCKLGT FLASH 16-QFN
• Manufacturer: STMicroelectronics
• Type: Backlight, Flash, Movier

Specifications of STLD20CP1PQR

• Topology: PWM, Step-Up (Boost), Switched Capacitor (Charge Pump)
• Number Of Outputs: 2
• Internal Driver: Yes
• Type - Primary: Backlight, Flash/Torch
• Type - Secondary: White LED
• Frequency: 1.3MHz
• Voltage - Supply: 2.8 V ~ 6 V
• Voltage - Output: 17V
• Mounting Type: Surface Mount
• Package / Case: 16-QFN
• Operating Temperature: -40°C ~ 85°C
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -
• Efficiency: -
• Other names: 497-6924-2; STLD20CP1PQR

6.3
6.4
6.5
6.6
6.7
current reaches 5%. The eleventh pulse sets the LED current back to I
shows a timing diagram for single-wire pulse dimming.
Analog dimming can be achieved by connecting a resistor network to the FB pin
Peak inductor current limitation and soft start function
An integrated current sensor will sense the peak drain current of the switch P_SW in order
to keep the inductor current below its saturation level. Since the peak drain current exceeds
the fixed limit I
During start up, this peak drain current limitation behaves inherently as a soft-start function.
Charge pump
The charge pump includes soft-start circuitry to limit inrush current at turn-on or when the
device changes operation from x1 to x2. During the soft-start time, the output current is set
to 10% of the maximum set by R
V
At start-up, the pin OUT_CP goes to V
V
condition. Otherwise, if V
bringing V
The device will change back to 1x mode when the input voltage rises above V
approximately 50 mV.
Current on power LED (flash)
The current that level flowing through the power LED in both modes (torch and flash) can be
selected using the following formula:
I
where K is a value of approximately 1220.
Figure 10
one camera shot, while
Over-voltage and short-circuit protection
In case of open-circuit failure of the power LED, the output voltage is limited to about 5.5 V
by gating the charge pump on/off.
If the power LED experiences a short-circuit or if the output charge pump is grounded, the
charge pump is turned off.
Start-up procedure
Before inserting the driving preferences with the digital pins it is mandatory to turn on the
device with correct supply voltage with all the digital pins set to GND.
FLASH
FB_CP
FB_CP
= K (0.6/R
reaches regulation. This function is implemented to avoid battery stress.
>150 mV, the LED current is regulated and the device continues to operate in a 1x
OUT_CP
shows the relationship between the TF signal control and flash duration time for
PK
by the drain current reference, the comparator turns off the switch P_SW.
FL
>V
), I
IN
. allowing LED current regulation.
TORCH
Figure 11
FB_CP
= K (0.6/R
<150 mV, the device changes to a 2x operating condition
TH
represents multiple shots.
or R
IN
TH
FL
, working in an x1 condition. Following this phase, if
)
(depending on the state of the SEL pin), until
LED
max.
OUT_CP
Figure 8
(Figure
by
11/19
9).