论文标题
具有灵活和高性能PWM调光控制的多个字符串LED驱动器
Multiple string LED driver with flexible and high performance PWM dimming control
论文作者
论文摘要
驱动多个LED字符串的主要目标包括实现均匀的电流控制和所有字符串的高性能PWM调光。这项工作提出了一个新的多重字符串LED驱动程序，不仅可以实现当前平衡，而且还达到了每个字符串的灵活范围PWM调光比。驱动程序中采用了紧凑的单对电感多输出拓扑，并配有同步集成器和可变的调光频率，以达到高效率和高性能变暗。通过使用提出的变量调光频率方案，将高光频率应用于具有高光比的字符串，这有助于将LED字符串电流的偏差保持在可接受的范围内，而低光频率则应用于具有低调比率的字符串，这有助于实现向下的LED LED电流波形。同时，新的时间多路复用控制方案会自动优化LED字符串的总线电压，从而最大程度地减少每个字符串的功率损耗。构建了三个字符串LED驱动器原型，以验证人民控制方案的有效性，在该方案中，这三个字符串可以在4％至100％之间具有不同的调光比。
The main objectives in driving multiple LED strings include achieving uniform current control and high performance PWM dimming for all strings. This work proposes a new multiple string LED driver to achieve not only current balance, but also flexible and wide range PWM dimming ratio for each string. A compact single-inductor multiple-output topology is adopted in the driver, accompanied by synchronous integrators and variable dimming frequency, to achieve both high efficiency and high performance dimming. By using the proposed variable dimming frequency scheme, high dimming frequency is applied to a string with high dimming ratio, which helps to maintain the deviation of LED string current in an acceptable range, while low dimming frequency is applied to a string with low dimming ratio, which helps to achieve rectangular LED current waveform. Meanwhile, the new time multiplexing control scheme automatically optimizes the LED string's bus voltages, thus minimizes each string's power loss. A three string LED driver prototype is constructed to validate the effectiveness of the peoposed control scheme, where the three strings can have different dimming ratios between 4% and 100%.
