TPS61196EVM-600

EVAL BOARD LED DRIVER TPS61196

Thisuser’sguidecontainsbackground information for theTPS61196aswell assetupandoperation instructionsfor theTPS61196EVM-600evaluationmodule(EVM).Alsoincludedaretest results,printed circuitboard(PCB) layouts,schematics,andthebillofmaterials(BOM)fortheEVM.

1 Introduction

TI's TPS61196EVM-600 evaluation module contains the TPS61196 integrated circuit (IC), a six-channel, 400-mA WLED driver. The TPS61196 provides a highly-integrated solution for LCD TV backlight with an independent PWM dimming function for each channel. This EVM helps designers evaluate the operation and performance of the TPS61196. The EVM contains one DC/DC converter as shown in Table 1.

1.1 Performance Specification Summary HTSSOP

The EVM is designed to operate from an input voltage source ranging from 10 V–30 V, and provides a continuous 200-mA output current for each string. The OVP voltage is set to 60 V but can be adjusted for the specific application. Table 2 provides a summary of the TPS61196EVM-600 performance specifications. All specifications are given for an ambient temperature of 25°C.

2 Jumper and Connector Setup

This section describes the jumpers and connectors on the EVM as well and how to properly connect, set up and use the TPS61196EVM-600.

2.1 Input/Output Connector Description

J1– Input: This header is the power input terminals for the converter. The terminal block provides a power (VIN ) and ground (GND) connection to allow the user to attach the EVM to a cable harness.

J3– 8-pin Connector: This header provides connections to the boost converter output (VOUT ) and the six current feedback lines (IFBx). With a 8-pin ribbon cable, this header can be connected to six LED strings, to facilitate evaluation.

J4– FAULT: This header is a fault indicator to indicate abnormal conditions. When the TPS61196 is operating normally, the voltage at the FAULT pin is low. When a fault condition happens, it is in high impedance, which can be pulled to high level through an external resistor.

J5– PWMCombination: This header provides flexible PWM control, PWM1–PWM6 can be controlled together by one PWM signal or can be controlled by six independent PWM signals.

J6– GND: This header connects to GND.

JP1, JP3 to JP7– IFB1 to IFB6: These jumpers are used to enable IFBx channels. Shorting pin 1 and pin 2 enables the IFBx channel and shorting pin 2 and pin 3 disables the corresponding channel.

JP2– EN: This jumper is used to enable the device. Connecting pin1 and pin2 will toggle the EN high and enable the device. Connecting pin2 and pin3 will toggle the EN low and disable the device.

JP8– PWM: This jumper is used to send a high or low signal to the J5 jumper. Connecting pin1 and pin2 will send a high signal to J5. Connecting pin2 and pin3 will send a low signal to J5.

2.2 Setup

This EVM requires an external power supply capable of providing 10 V to 30 V at 5 A. To change the default current value (that is, implement dimming), the user can apply either a PWM signal to JP8-pin2 and connect PWM1–PWM6 together, or apply six independent PWM signals to PWM1–PWM6.

The hardware connections of TPS61196EVM-600:

• TheDCpower supply is connected between J1-pin1 and J1-pin2.

• TheLEDarray is connected to the J3.

• Theone single PWM dimming signal can be connected to JP8-pin2, six independent PWM dimming signals can be connected to J5-pin 2, 4, 6, 8, 10, 12.

The range of dimming frequency is 90 Hz to 22 kHz. The output overvoltage protection is set to 60 V, which can be adjusted by R7 in SCH, then can drive different series number of LEDs. To ensure the TPS61196EVM-600 operates properly, the minimum output voltage of the board should be more than input power voltage. This requires selection of the LED array carefully to make sure the total forward voltage of the series LEDs is more than the input voltage.

Figure 1 shows the default configuration of the jumpers.

3 Operation

This section contains non-dimming and PWM-dimming operation instructions, and EVM test results.

3.1 Non-Dimming Operation (Default Configuration)

For non-dimming operation of the TPS61196EVM-600; J5, JP2, and JP8 should be properly configured as shown in Figure 1. The configuration for JP1 and JP3 to JP7 is determined by the specific application. In this default configuration, the device will power up when power is applied.

3.2 PWM-Dimming Operation

Remove the jumper on JP8 of the default configuration, connect the appropriately configured function generator output between JP8-pin2 and JP8-pin3 (for GND connection) to control PWM1–PWM6 together, or connect six independent PWM signals between J5-pin2, 4, 6, 8, 10, 12 and GND to control PWM1–PWM6. The PWM signal's duty cycle is directly proportional to the regulated current.

3.3 Test Results

Figure 2 and Figure 3 provide typical efficiency for the TPS61196EVM-600 board.

4 Board Layout

Figure 4, Figure 5, and Figure 6 show the board layout for the TPS61196EVM-600. The EVM offers resistors, capacitors and jumpers. Jumpers are provided to configure the device.

5 Schematics

Figure 7 illustrates the schematic for this EVM.