LM3492-Q1数据手册TI中文资料规格书

描述 Description

The LM3492/-Q1 integrates a boost converter and a two-channel current regulator to implement a high efficient and cost effective LED driver for driving 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, and a nearly constant switching frequency programmable from 200 kHz to 1 MHz. The application circuit is stable with ceramic capacitors and produces no audible noise on dimming. The programmable peak current limit and soft-start features reduce current surges at start-up, and 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 1000:1 at a dimming frequency of more than 3 kHz. The LED current is programmable from 50 mA to 200 mA by a single resistor.

To maximize the efficiency, Dynamic Headroom Control (DHC) automatically adjusts the output voltage to a minimum. DHC also facilitates a single BOM for different number of LED in a string, which is required for backlight panels of different size, thereby reducing overall development time and cost. The LM3492/-Q1 comes with a versatile COMM pin which serves as a bidirectional I/O pin interfacing with an external MCU for the following functions: power-good, overtemperature, IOUT overvoltage and undervoltage indications, switching frequency tuning, and channel 1 disabling. Other supervisory functions of the LM3492/-Q1 include precise enable, VCC undervoltage lockout, current regulator over-power protection, and thermal shutdown protection. The LM3492/-Q1 is available in the thermally enhanced 20-pin HTSSOP package.

特性 Features

• Boost Converter:
• LM3492-Q1 is an Automotive Grade Product That is AEC Q100 Grade 1 Qualified
• Very Wide Input Voltage Ranged From 4.5 V to 65 V
• Programmable Soft Start
• 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 Regulators:
• Programmable LED Current from 50 mA to 200 mA
• 1000:1 Contrast Ratio at a Dimming Frequency of More Than 3 kHz, Minimum LED Current Pulse Width is 300 ns
• 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 20-Pin HTSSOP package