1 Features

1• Boost Converter

– Automotive Grade Product, Q100 Grade-1

Qualified

– Very Wide Input Voltage Range: 4.5 V to 65 V

– Programmable Soft-Start Period

– No Loop Compensation Required

– Stable with Ceramic and Other Low ESR

Capacitors with No Audible Noise

– Nearly Constant Switching Frequency

Programmable from 200 kHz to 1 MHz

• Current Regulator

– Programmable LED Current: 50 mA to 250 mA

– 10000:1 Contrast Ratio, 300-ns Minimum

Pulse Width

– Two Individual Dimmable LED Strings up to

65 V, Total 15 W (Typically 28 LEDs at

150 mA)

– Dynamic Headroom Control Maximizes

Efficiency

– Over-Power Protection

– ±3% Current Accuracy

• Supervisory Functions

– Precision Enable

– COMM I/O Pin for Diagnostic and Commands

– Thermal Shutdown Protection

– Thermally Enhanced PWP, 20-Pin Package

2 Applications

• Ultra-High Contrast Ratio 6.5” to 10” LCD Display

Backlight up to 28 LEDs

• Automotive or Marine GPS Display

3 Description

The LM3492HC/-Q1 device integrates a boost converter and a two-channel current regulator to

implement a highly efficient and cost effective LED

driver. This device drives two individually dimmable

LED strings with a maximum power of 15 W and an

output voltage of up to 65 V. The boost converter

employs a proprietary projected-on-time control

method to give a fast transient response with no

compensation required. The nearly constant

switching frequency can be set to a level from 200

kHz to 1 MHz. Ceramic capacitors stabilize the

application circuit and produce no audible noise on

dimming. The programmable peak current limit and

soft-start features reduce current surges at start-up.

An integrated, 190-mΩ, 3.9-A, N-Channel MOSFET

switch minimizes the solution size. The fast slew rate

current regulator allows high frequency and narrow

pulse width dimming signals to achieve a very high contrast ratio of 10000:1. The LED current can be set

from 50 mA to 250 mA by a single resistor.