基于可见光通信的LED载流子清除电路设计

LED circuit with drawing-out of carrier based on visible light communication

可见光通信由LED附加高低脉冲驱动电压来发射光信号,随着发射速率增高,LED正偏脉冲电压负跳变瞬间,结电容仍聚集大量的过剩载流子,存在微弱的复合发光,LED也就无法完全熄灭,影响LED的光通信性能。为解决这一问题,提出一种低成本、快速清除载流子的LED驱动改进电路,在LED熄灭瞬间,使之接入短路回路,从而快速释放载流子,进而快速降低LED端电压。实验表明,改进电路使得发射端电压波形下降沿时间从传统电路的约200 ns下降为15 ns,接收端电压下降时间从85 ns下降为约58 ns,系统性能得到提升。

Visible light communication uses LED to emit light signals by appending high and low pulse driving voltage.With the increase of emission rate,when the positive and negative pulse voltage of LED changes,the junction capacitance still aggregates a large number of excess carriers,and there is a weak composite light can not be completely extinguished,which will affect the optical communication performance of LED.A LED driver circuit with low cost and fast carrier clearance was proposed.When the LED went out,the circuit was connected to the short-circuit loop,so as to release the carrier quickly and reduce the LED terminal voltage rapidly.The experimental results showed that the drop time of the voltage waveform at the transmitter was reduced from 200 to 15 ns,while the drop time at the receiver was reduced from 85 to 58 ns,indicating that the performance of the system was improved.