On Semi公司的NCL30051是峰值電流控制固定關斷時間的降壓控制器,適合用于LED驅動器應用,可調整關斷時間,源250mA/沉500mA峰值驅動能力, 25°C時的電流檢測精度±3.2%,3.3V電平調光輸入,具有熱關斷,過流保護和最大開態時間保護,主要用于LCD屏的LED背光驅動器,LED條燈,LED街燈和LED燈泡.本文介紹了NCL30051主要特性,方框圖, 典型應用電路圖, 輸入80V 350mA輸出的降壓LED驅動器評估板NCL30105GEVB電路圖,材料清單和PCB布局圖.

The NCL30105 is a peak current controlled fixed off time buck controller designed for LED driver applications. It is optimized to operate in deep continuous conduction mode ELiminating the need for output electrolytic capacitors. Featuring an adjustable off time generator, the controller can drive a MOSFET up to a switching frequency of 500 kHz. A dedicated dimming pin enables the use of a pulsewidth modulated logic signal to dim the LED directly. The soft-start pin creates a startup sequence that slowly ramps up the peak current and enables the adjustment of the peak current set point for analog dimming control. The device features robust protection features to detect switch overcurrent faults and to detect maximum on time events.

NCL30051主要特性:

? Constant Off Time Current?Mode Control Operation

? Adjustable Off Time (0.5 [1]s to 10 [1]s)

? Internal Leading Edge Blanking

? Source 250 mA / Sink 500 mA Peak Drive Capability

? ±3.2% Current Sense Accuracy at 25℃? Internal Startup Delay

? 3.3 V Logic Level Dimming Input

? This is a Pb?Free Device

NCL30051安全特性:

? Thermal Shutdown

? Maximum On Time Protection

? Overcurrent Protection

NCL30051典型應用:

? LED Backlight Drivers for LCD Panels

? LED Light Bars

? LED Street Lighting

? LED Bulbs

圖1.NCL30051方框圖

圖2.NCL30051典型應用框圖

圖3.NCL30051典型應用電路圖

圖4. 評估板NCL30105GEVB外形圖:輸入高達80V,輸出350mA
圖5. 評估板NCL30105GEVB電路圖(1)

圖6. 評估板NCL30105GEVB電路圖(2)
評估板NCL30105GEVB材料清單:



圖7. 評估板NCL30105GEVB元件布局圖:頂層

圖8. 評估板NCL30105GEVB元件布局圖:底層