请教LED问题
我想做一只照明灯,输入AC220V,71只20mA LED串联,其电源部分应怎样设计,请高手指教
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面向LED照明应用推出变压控制器IC- HV9921/22
Supertex公司推出的HV9921/22系列三引脚恒流IC适用于驱动标志及普通照明设备中的低电流LED灯组.这些变压控制器芯片可通过带前端整流器的20Vdc到250Vdc的通用电源供电.其中,HV9921能输出20mA电流,而HV9922则能提供50mA电流.
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在用于内部输出功率MOSFET级时,这些降压PWM控制器/驱动器的断路时间固定为10us,从而能为LED灯组提供约输入电压80%的电压值.其MOSFET的额定电压为500V,符合通用AC输入对于输入瞬态电压的要求.
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Supertex公司推出的HV9921/22系列三引脚恒流IC适用于驱动标志及普通照明设备中的低电流LED灯组.这些变压控制器芯片可通过带前端整流器的20Vdc到250Vdc的通用电源供电.其中,HV9921能输出20mA电流,而HV9922则能提供50mA电流.
500) {this.resized=true; this.width=500; this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/52/63961177600066.jpg');}" onmousewheel="return imgzoom(this);">
在用于内部输出功率MOSFET级时,这些降压PWM控制器/驱动器的断路时间固定为10us,从而能为LED灯组提供约输入电压80%的电压值.其MOSFET的额定电压为500V,符合通用AC输入对于输入瞬态电压的要求.
500) {this.resized=true; this.width=500; this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/52/63961177600101.jpg');}" onmousewheel="return imgzoom(this);"> 0
@文子
面向LED照明应用推出变压控制器IC-HV9921/22 Supertex公司推出的HV9921/22系列三引脚恒流IC适用于驱动标志及普通照明设备中的低电流LED灯组.这些变压控制器芯片可通过带前端整流器的20Vdc到250Vdc的通用电源供电.其中,HV9921能输出20mA电流,而HV9922则能提供50mA电流.[图片]500){this.resized=true;this.width=500;this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}"onclick="if(!this.resized){returntrue;}else{window.open('http://u.dianyuan.com/bbs/u/52/63961177600066.jpg');}"onmousewheel="returnimgzoom(this);"> 在用于内部输出功率MOSFET级时,这些降压PWM控制器/驱动器的断路时间固定为10us,从而能为LED灯组提供约输入电压80%的电压值.其MOSFET的额定电压为500V,符合通用AC输入对于输入瞬态电压的要求.[图片]500){this.resized=true;this.width=500;this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}"onclick="if(!this.resized){returntrue;}else{window.open('http://u.dianyuan.com/bbs/u/52/63961177600101.jpg');}"onmousewheel="returnimgzoom(this);">
ZD831
The ZD831 is a high voltage, transformerless AC-DC constant current driver for driving a string of white or RGB LEDs in series. It operates from an universal input voltage of 85VAC to 240VAC and generates a programmable constant output current. The high operating voltage of ZD831, along with its linear control architecture eliminates the need for an external inductor, transformer and rectifying diode bridge. The output current level is set by a single resistor and can be set as high
as 30mA. Dimming control can be accomplished by using pulse-width modulation signal with varying duty cycle on the PWM pin or by applying an analog DC voltage on the ISET pin. Thermal and over-voltage circuitry protects the internal power transistors from excessive power dissipation.
The ZD831EVB is confi gured for application using 110VAC or
240VAC (details in the Typical Applications section) operation
by default settings from factory.
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The ZD831 is a high voltage, transformerless AC-DC constant current driver for driving a string of white or RGB LEDs in series. It operates from an universal input voltage of 85VAC to 240VAC and generates a programmable constant output current. The high operating voltage of ZD831, along with its linear control architecture eliminates the need for an external inductor, transformer and rectifying diode bridge. The output current level is set by a single resistor and can be set as high
as 30mA. Dimming control can be accomplished by using pulse-width modulation signal with varying duty cycle on the PWM pin or by applying an analog DC voltage on the ISET pin. Thermal and over-voltage circuitry protects the internal power transistors from excessive power dissipation.
The ZD831EVB is confi gured for application using 110VAC or
240VAC (details in the Typical Applications section) operation
by default settings from factory.
500) {this.resized=true; this.width=500; this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/52/63961177600476.jpg');}" onmousewheel="return imgzoom(this);"> 0
