Susie Maestre

user Electronics Engineer

city Innovuze Solutions Inc.


  • TPS92515 High Current Buck LED Driver

  • Created: Oct 11, 2016

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Description

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Summary

The reference design as shown features TPS92515 buck switching regulator designed for high-current LED drive applications. This is particularly designed to control the drive of high-brightness LEDs. The TPS92515 features a wide input voltage range (5.5V to 65V), PWM dimming capability, analog dimming capability, and input undervoltage protection. Furthermore, the TPS92515 has an internal N-channel MOSFET hysteric control. Hysteric operation allows a high control bandwidth and is ideal for shunt FET and LED matrix applications.


The TPS92515 regulator operates using a constant OFF time, peak current control. The operation is simple: after an OFF time based on the output voltage, an ON time begins. The ON time ends once the inductor peak current threshold is reached. The TPS92515 device can be configured to maintain a constant peak-to-peak ripple during the ON and OFF periods of a shunt FET dimming cycle. This is ideal for maintaining a linear response across the entire shunt FET dimming range. In this circuit, the connector J1 is used to change the LED current default setting. The default setup is a shunt placed between pins 1 and 2 resulting in an output current of 1A. The output current can be adjusted by applying voltage to IADJ pin while the shunt is removed. The connector J2 is used for connecting the LED load to the board. The leads to the LED load should be twisted and kept as short as possible to minimize voltage drop, inductance, and EMI transmission. Pin 1 of the connector is GND and LED– while pin 2 is LED+. This design is for approximately 1 to 18 white LEDs. The connector J3 is used for connecting the circuit to the DC input voltage supply. The input supply ground should be connected to pin 1 or 2 of J3 while the positive input is connected to pin 3.


This design is useful in high-brightness LED lighting applications where efficiency, high bandwidth, PWM and analog dimming and small size are important. It can be used in automotive lighting such as LED-switched matrix headlamps, high/low, fog, rear, and turn signals. It has also an importance in industrial light such as in factory automation, time of flight (TOF), retail illumination, medical lighting, stage, and area lighting.