基于升压，升降压的高压LED驱动芯片设计
Design of a High Voltage LED Driver Based on Boost or Buck-Boost Converter

设计了一款根据外围应用电路的不同可以实现升压以及升降压型的宽输入电压范围的恒流LED驱动芯片，该芯片输入电压高达35 V，输出电压不限。驱动电流可由外接电阻设置，可以驱动高达48 W的大功率LED灯，工作的开关频率可由外部电阻设置，调节范围100 KHz~1 MHz。该款芯片具有丰富的调光功能，包括模拟，数字转模拟以及数字调光，内部自带软启动、过温保护、欠压，过压等保护功能。采用HHNEC PMU350，5V/40V工艺完成芯片的设计，转换效率可达85％以上，采用TSSOP-16的封装，外围应用电路简单，无需大电感，是目前推向市场的一款功能丰富的升降压型芯片。
A Boost/Buck-Boost Topology constant current LED driver IC was proposed, of which the input voltage is up to 35 V, and output voltage is unlimited. This IC regulates the LED current by setting the external resistor, and can drive up to 48 W high power LED lighting. The operating frequency also can be set up by external resistor, ranging from 100 KHz to 1 MHz. The IC has rich dimming functions, including analog, digital to analog and digital dimming, with built-in soft start, over-temperature protection, undervoltage, overvoltage and other protection functions. The IC is de-signed and fabricated in HHNEC PMU350, 5V/40V process, with a power conversion efficiency up to 85%, available in TSSOP-16 package, without large inductance, and has simple application circuit. This IC is a powerful DC-DC converter pushing to the market.