TL4242QKTTRQ1 Datasheet, PDF (1/21 Pages) Texas Instruments – ADJUSTABLE LED DRIVER

TL4242-Q1
www.ti.com
SLVS732E – JULY 2010 – REVISED JULY 2013
ADJUSTABLE LED DRIVER
Check for Samples: TL4242-Q1
FEATURES
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• Qualified for Automotive Applications
• AEC-Q100 Test Guidance With the Following
Results:
– Device Temperature Grade 2: –40°C to
105°C Ambient Operating Temperature
Range for QFN package
– Device Temperature Grade 1: –40°C to
125°C Ambient Operating Temperature
Range for SFM package
– Device HBM ESD Classification Level H1C
– Device CDM ESD Classification Level C3B
• Adjustable Constant Current
up to 500 mA (±5%)
• Wide Input-Voltage Range up to 42 V
• Low Dropout Voltage
• Open-Load Detection
• Overtemperature Protection
• Short-Circuit Proof
• Reverse-Polarity Proof
DRJ (QFN) PACKAGE
(TOP VIEW)
PWM 1
8I
ST
GND
2 ^Exposed 7 NC
Thermal
3 Pad 6 Q
REF 4
5D
NC – No internal connection
KTT (SFM) PACKAGE
(TOP VIEW)
1 234 567
I ST REF Q
PWM GND D
DESCRIPTION
The TL4242-Q1 is an integrated adjustable constant-current source, driving loads up to 500 mA. One can adjust
the output current level through an external resistor. The device design is for supplying high-power LEDs (for
example, OSRAM Dragon LA W57B) under the severe conditions of automotive applications, resulting in
constant brightness and extended LED lifetime. The device comes in the DRJ (QFN) package. Protection circuits
prevent damage to the device in case of overload, short circuit, reverse polarity, and overheat. The device
provides the connected LEDs protection against reverse polarity as well as excess voltages up to 45 V.
The integrated PWM input of the TL4242-Q1 permits LED brightness regulation by pulse-width modulation
(PWM). The high input impedance of the PWM input, allows operating the LED driver as a protected high-side
switch.
An external shunt resistor in the ground path of the connected LEDs senses the LED current. A regulation loop
holds the voltage drop at the shunt resistor at a constant level of 177 mV (typical). The selection of the shunt
resistance, R_REF, sets the constant-current level. Calculate the typical output current using the equation:
I_Q,typ
=
V_REF
R_REF
where V_REF is the reference voltage (typically 177 mV) (see Reference Electrical Characteristics). The equation
applies for R_REF = 0.39 Ω to 10 Ω.
The output current is shown as a function of the reference resistance in . With the PWM input, One can regulate
the LED brightness through the duty cycle. Also, PWM = L sets the TL4242-Q1 in sleep mode, resulting in a very
low current consumption of < 1 μA (typical). The high impedance of the PWM input (see ) permits the use of the
PWM pin as an enable input.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
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