基于LCLC恒流网络的LED自均流电路

发布时间：2018-08-23 08:17

【摘要】：多路半导体发光二极管(light-emitting-diode,LED)并联会造成导通电流不均衡,而电容均流方案由于其简单可靠得到广泛应用。为输出所需的LED电流,电容均流方案采用变频控制会引入无功环流,提高器件应力,而采用定频占空比控制时,变化的LED负载难以保证零电压开关(zerovoltage switching,ZVS)的实现。针对此问题,文中提出一种基于LCLC谐振网络的恒流源输出LED驱动电路,可有效解耦负载对输出电流的影响,定频控制,且同时实现输入阻抗为纯阻性,避免无功环流。该谐振网络亦结合电容均流方案,采用较少的器件实现多路均流。此外,该电路具有短路自保护功能,易于实现脉宽调制(pulse width modulation,PWM)调光。最后,以4条LED支路为例,搭建实验样机,实验结果证明该电路的有效性。
[Abstract]:The parallel connection of light-emitting-diode (LED) leads to the imbalance of the on-current, and the capacitive current-sharing scheme is widely used because of its simplicity and reliability. In order to output the required LED current, the variable frequency control of capacitor current sharing scheme will introduce reactive power circulation and improve the device stress. However, when the constant frequency duty cycle control is adopted, it is difficult to guarantee the realization of zerovoltage switching (zerovoltage switching / ZVS) when the variable LED load is controlled. To solve this problem, a constant current source output LED drive circuit based on LCLC resonant network is proposed, which can effectively decouple the effect of load on output current, control frequency, and realize the pure resistance of input impedance and avoid reactive circulation at the same time. Combined with capacitive current sharing scheme, the resonant network uses fewer devices to realize multi-channel current sharing. In addition, the circuit has the function of short circuit self-protection and is easy to realize pulse width modulation (pulse width) dimming. Finally, the experimental prototype is built with four LED branches as an example. The experimental results show that the circuit is effective.
【作者单位】：东南大学电气工程学院;香港理工大学电子及资讯工程学系;
【基金】：国家自然科学基金项目(51107009) 江苏省自然科学基金项目(BK20141339)~~
【分类号】：TM923.34

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