STLD40DPUR STMicroelectronics, STLD40DPUR Datasheet - Page 7

• Manufacturer Part Number: STLD40DPUR
• Description: IC LED DRIVER WHITE BCKLGT 8-QFN
• Manufacturer: STMicroelectronics
• Type: Backlight, White LEDr

Specifications of STLD40DPUR

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Voltage - Supply: 3 V ~ 5.5 V
• Voltage - Output: 37V
• Mounting Type: Surface Mount
• Package / Case: 8-QFN
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 20mA
• Internal Switch(s): Yes
• Efficiency: 80%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency: -
• Lead Free Status / Rohs Status: Details
• Other names: 497-8927-2

STLD40D
5
5.1
5.2
5.3
5.4
Functional description
Boost controller
The STLD40D is a boost converter operating in PFM (pulsed frequency modulation) mode.
The converter monitors the LED current through the resistor R
voltage falls below the reference voltage REF2, the boost switch T
current ramps up. The inductor current is measured by sensing the temperature
compensated drain voltage of the boost MOSFET. The boost turns off when its drain voltage
reaches the internally reference REF1, the main switch remains off until the minimum off
time (250 ns typical) has passed and the feedback voltage is below the reference again. A
maximum ON time of 4 µs typical prevents the switch T
period of time.
Adjustable peak inductor current limit
The peak inductor current is monitored by sensing the drain voltage of the switch T
it exceeds the temperature compensated and supply voltage compensated reference REF1,
the RS flip flop is reset and T
the peak current limit can be adjusted from 200 mA to 1 A. When R
about 12 k
Enable
The ENABLE pin is a high logic input signal and allows turning on/off the controller without
cutting the input voltage from the boost regulator circuit. The pin ENABLE can be used to
dim the LED by applying a low frequency PWM signal.
OVP
If the regulation loop is cut, there is no signal at the feedback pin, the PFM controller will then
continue to switch without control and generate an output voltage at the SW, and V
exceeding the breakdown value V
The over voltage protection (OVP) senses the voltage at the V
exceed 38 V min. the controller is automatically turned OFF.
A hysteresis control allows the device restarting automatically since the output voltage drops
down of 1.5 V.
Ω
is connected directly to GND, the default value is 1 A.
SW
Doc ID 12203 Rev 6
is turned OFF. By connecting a resistance to the pin R
BSW
, and V
BO
.
SW
to stay ON during a too long
O
LED
pin. When the voltage
SW
and when the feedback
Functional description
SET
turns ON and the
resistor value is
SW
O
. Since
pin
SET
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