Holtek公司的HT7939是大電流和高性能白光LED驅(qū)動器,輸入電壓從2.6V到5.5V,固定開關(guān)頻率1.2MHz,內(nèi)置功率MOSFET,5V輸入時可驅(qū)動39個白光LED,DD電流通過外部電阻設(shè)定,待機(jī)電流產(chǎn)0.1uA,效率高達(dá)90%,集成了過壓保護(hù),超溫保護(hù)和過流保護(hù).主要用在顯示器背光照明,DVD播放器,數(shù)碼相框,手持計(jì)算機(jī),LED照明和自動化.本文介紹HT7939主要特性,方框圖和多種應(yīng)用電路,包括驅(qū)動39個WLED應(yīng)用電路圖,采用PWM邏輯信號和DC電壓的調(diào)光控制應(yīng)用電路圖以
Holtek 公司的HT7939是大
電流和高性能白光
LED驅(qū)動器,輸入電壓從2.6V到5.5V,固定
開關(guān)頻率1.2MHz,內(nèi)置
功率MOSFET,5V輸入時可驅(qū)動39個白光LED, DD電流通過外部
電阻設(shè)定,待機(jī)電流產(chǎn) 0.1uA,效率高達(dá)90%,集成了過壓保護(hù),超溫保護(hù)和過流保護(hù).主要用在顯示器背光照明,DVD播放器,數(shù)碼相框,手持計(jì)算機(jī),LED照明和自動化.本文介紹HT7939主要特性, 方框圖和
多種應(yīng)用電路,包括驅(qū)動39個WLED應(yīng)用電路圖, 采用PWM邏輯信號和DC電壓的調(diào)光控制應(yīng)用電路圖以及驅(qū)動3個高亮LED應(yīng)用電路圖等.
HT7939: High Current and Performance White LED Driver
The HT7939 is a high eff
iciency boost converter for driving White LEDs using current mode operation. The device is designed to drive up to 39 White LEDs from a 5V power supply. The White LED current is setup using an external current setting resistor, which has a low feedbackvoltage of 0.2V to minimise power losses in the resistor which improves efficiency. The Over-voltage function prevents damage to the IC by turning off the converter when the LED load is open circuit.
The device includes over current protection, over temperature protection and under voltage protection preventingdamage to the device when the
output is overloaded.
HT7939主要特性:
_ Input range from 2.6V~5.5V
_ Built-in Power MOSFET
_ Can drive up to 39 White LEDs with a 5V input
_ Low standby current: 0.1uA (
typ.) with VEN low
_ Integrated Over-voltage, Over-temperature and Over-current protection circuits
_ Under voltage lock-out protection
_ 1.2MHz fixed switching frequency
_ High efficiency - up to 90%
_ 6-
pinSOT23-6 package
