HV9918中文资料Hysteretic, Buck, High Brightness LED Driver w/ High-Side Current Sensing数据手册Microchip规格书

描述 Description

The HV9918 is a PWM controller IC designed to drive high brightness LEDs using a buck topology. It operates from an input voltage of 4.5 to 40VDC and employs hysteretic control with a high-side current sense resistor to set the constant output current up to 700mA. The device is well suited for applications requiring a wide input voltage range. The high-side current sensing and an integrated current-setting circuitry minimize the number of external components while delivering an accurate average output. Dedicated pulse-width modulation (PWM) input enables pulsed LED dimming over a wide range of brightness levels. A hysteretic control method ensures excellent input supply rejection and fast response during load transients and PWM dimming.The HV9918 offers an analog-controlled PWM dimming feature that reduces the output current by applying an external DC voltage below the internal 2.0V threshold voltage from ADIM to GND. ADIM can also accept input from a resistor divider including a negative temperature coefficient (NTC) thermistor connected between ADIM and GND, or a positive temperature coefficient (PTC) thermistor connected between ADIM and VDD thus providing a PWM thermal-foldback feature that reduces the LED current when the temperature of the LED string exceeds a specified temperature point. Additional features include thermal-shutdown protection.The high switching frequency up to 2.0MHz permits the use of small inductors and capacitors, minimizing space and cost in the overall system. The HV9918 comes in a small 8-Lead DFN package and is ideal for industrial and general lighting applications.

特性 Features

Hysteretic control with high-side current sensing
Integrated 40V 1.0O MOSFET
>90% Efficiency
Wide input voltage range: 4.5 to 40V
±5% LED current accuracy
Up to 2.0MHz switching frequency
Adjustable constant LED current
Analog or PWM control signal for PWM dimming
Over-temperature protection
-40ºC to +125ºC operating temperature range

简介

HV9918属于集成电路（IC）的LED驱动器。由制造生产的HV9918LED 驱动器器件属于 LED 驱动器电源管理集成电路 (PMIC) 系列，可通过标称固定电压的电源为负载（通常为发光二极管）提供电流，并且电流可控。它与用于电压调节的类似产品的主要区别在于，这类器件提供较低的反馈电压（以提高系统能效），而且通常可对器件工作点进行外部控制，可在照明应用中用于实现调光功能。