Description
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SLVUAR5 – May 2016
Copyright © 2016, Texas Instruments Incorporated
TPS92515HVEVM-749 High Current Buck LED Driver Evaluation Module
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Description
The TPS92515HVEVM-749 provides a high-brightness LED driver based on the TPS92515 buck
regulator. It is designed to operate with an input voltage in the range of 5.5 V to 65 V. The EVM is set up
for a default output current of 1 A for an LED stack between approximately 3 V and nearly 65 V. The
TPS92515 helps provide high efficiency, fast PWM dimming, and accurate wide-range analog dimming.
3.1
Typical Applications
This converter design describes an application of the TPS92515 as an LED driver with the specifications
listed in
. For applications with a different input voltage range or different output voltage range refer
to the TPS92515 datasheet (
3.2
Features
3.2.1
Connector Description
This section describes the connectors and test points on the EVM and how to properly connect, setup,
and use the TPS92515HVEVM-749.
3.2.1.1
J1, LED Current Setting
A three pin header, 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 1 A. The shunt can be moved to pins 2 and
3 which will change the output current to 1.5 A. Alternatively, the output current can be adjusted by
applying a voltage to TP1 (IADJ) with the shunt removed.
3.2.1.2
J2, LED+, LED–/GND
The screw-down connector J2 is 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.
3.2.1.3
J3, VIN, GND
The screw-down connector J3 is for connecting the EVM 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.
3.2.1.4
TP1, IADJ
TP1 connects directly to the IADJ pin of the TPS92515. An analog voltage applied to IADJ will adjust the
peak inductor current level providing an analog dimming function.
3.2.1.5
TP3, PWM
The PWM test point connects directly to the PWM pin of the TPS92515. Leave R14 connected for normal
operation. If PWM dimming is used, remove R14 and apply a square wave with a low level of GND and a
high level of between 2.5 V and 5 V. The dimming frequency range is 100 Hz to 10k Hz.
3.2.2
High Speed Shunt FET Dimming
The TPS92515HVEVM-749 is capable of high speed shunt FET dimming for fast PWM dimming and/or
extended PWM dimming range. To implement shunt FET dimming use an externally driven FET across
the LED load placed as close to the LED load as possible to minimize parasitic inductance. The EVM will
need minor modifications to the OFF timer due to shorting the output. Remove R1 and populate R4, R7,
and D3 as shown and calculated in the TPS92515 datasheet.