White LED Driver circuit using TPS61161A is designed to drive up to 8 White LEDs with minimum external components. IC TPS61161A from Texas Instruments is a boost converter, that drives LEDs in series. This IC runs at 600KHz fixed switching frequency to reduce output ripple, It ca operate with voltage Range from 2.7V to 18V and also has 38V open LED protection. We can use PWM interface for brightness control. This IC comes in WSON package.
IC TPS61161A driver circuit default LED current is set with the external sense Resistor Rset (R1) and the feedback voltage is regulated to 200mV. Here the control pin (CTRL) can be driven with external PWM signal for to dimming the brightness, in order to Continuously glow LED with maximum brightness we have connected CTRL pin with Vin supply through R2 Resistor.
Components Required (BOM)
|7||D2, D3, D4, D5, D6, D7, D8, D9||LED||LED_0805_2012Metric||8|
Construction & Working
Due to the WSON package and minimum external components we can design this White LED Driver in compact size PCB. Vin Supply is applied to the Vin pin and to the CTRL pin through R2 Resistor. White LEDs are Receives Vin Supply through L1 Inductor and D1 Schottky barrier diode.
Here between L1 and D1 Switching pin (SW) is connected. Feedback pin (fb) connected with series LEDs cathode end terminal and R1 Resistor, another end of R1 is grounded, here the fb pin used for current sense. COMP pin provides output of the transconductance error amplifier. Here capacitor connected for to compensate the Regulator. This IC can be used for Li-Ion battery powered applications. Refer datasheet for more information.
Printed Circuit Board
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