On Semi公司的NCP3065是高達1.5A恒流開關穩壓器,輸入電壓從3.0V到40V,反饋電壓235mV,工作頻率可調整到高達250kHz,逐個周期限流,主要用在汽車照明,大功率LED驅動器,恒流源已急低壓LED照明.本文介紹NCP3065主要特性, 方框圖, 典型降壓應用電路, 降壓演示板應用電路和材料清單, 升壓演示板應用電路和材料清單,以及1-5W MR16 LED驅動GreenPoin解決方案框圖,應用電路和材料清單.
NCP3065, NCV3065: Up to 1.5 A Constant Current Switching Regulator for LEDs The NCP3065 is a monolithic switching regulator designed to deliver constant current for powering high brightness LEDs. The device has a very low feedback voltage of 235 mV (nominal) which is used to regulate the average current of the LED string. In addition, the NCP3065 has a wide input voltage up to 40 V to allow it to operate from 12 Vac or 12 Vdc supplies commonly used for lighting applications as well as unregulated supplies such as Lead Acid batteries. The device can be configured in a controller topology with the addition of an external transistor to support higher LED currents beyond the 1.5 A rated switch current of the internal transistor. The NCP3065 switching regulator can be configured in Step−Down (Buck) and Step−Up (boost) topologies with a minimum number of external components.
NCP3065主要特性:
• Integrated 1.5 A Switch
• Input Voltage Range from 3.0 V to 40 V
• Low Feedback Voltage of 235 mV
• Cycle−by−Cycle Current Limit
• No Control Loop Compensation Required
• Frequency of Operation Adjustable up to 250 kHz
• Operation with All Ceramic Output Capacitors or No Output Capacitance
• Analog and Digital PWM Dimming Capability
• Internal Thermal Shutdown with Hysteresis
• Automotive Version Available
NCP3065應用:
• Automotive and Marine Lighting
• High Power LED Driver
• Constant Current Source
• Low Voltage LED Lighting
(Landscape, Path, Solar, MR16 Replacement)
圖1.NCP3065方框圖
圖2.NCP3065典型降壓應用電路
圖3.NCP3065降壓演示板應用電路
材料清單(BOM):
圖4.NCP3065升壓演示板應用電路
材料清單(BOM):
圖5.NCP3065降壓演示板應用電路(2)
材料清單(BOM):
1-5W MR16 LED驅動GreenPoin解決方案
This reference document describes a built and tested, GreenPoint® solution for a 1 to 5WLED driver for MR16 LED replacement. The circuit is proposed for driving HB--LED (high--brightness LED) in a variety of lighting applications but is configured in size and features for an MR16 LED replacement. Configurations like this are found in 12 Vac / 12 Vdc track lighting applications, automotive applications, and low voltage AC landscaping applications as well as task lighting such as under--cabinet lights and desk lamps that might be powered from standard off--the—shelf Vac wall adapters.
The circuit is based around the ON Semiconductor NCP3065 operating at ~150 kHz in a non—isolated configuration. A key consideration in this design was achieving flat current regulation across input line variation and output voltage variation with a 12 Vac input. It also features an auto--detect circuit in combination with the NCP3065 which allows input from a 12 Vdc or 12 Vac supply and still maintain targeted output current regulation.
圖6.1-5W MR16 LED驅動方框圖
圖7.1-5W MR16 LED驅動器外形圖
圖8.1-5W MR16 LED驅動器電路圖
材料清單:
