用于场致发光灯稳定驱动的Boost电路

Stable Boost Circuit of Electroluminescent Lamp Driver

稳定性是开关电源设计的技术指标之一。电压拓扑中影响稳定性的因素主要由误差放大器引入,电流拓扑相对于电压拓扑虽有不少改进,但也给电路稳定性带来了新的影响因素,特别是次谐波振荡问题。为使输出电压稳定,满足EL灯的使用要求,文中提出了一种稳定的用于EL灯驱动的Boost电路,该设计用带使能控制的电流比较器代替误差放大器,提高了电路的稳定性。文中详细分析了电路的工作过程,给出了电路的仿真结果。该电路响应时间为60μs,基准电流源为4.3μA,负载调整率为6%,电路稳定输出范围70～100V,适用于19.4cm2～38.7cm2(3in2～6in2)的EL灯。该电路结构简单、稳定性好、响应快、功耗低、易于集成。

Stability is an index to measure the quality of Switching Power Supply.The main factor that influences the stability of voltage-mode is caused by error amplifier.Compared to voltage-mode,current-mode improves a lot but introduces new factors,especially the sub-harmonic oscillation.This paper designed a Boost circuit which can insure the stability of output voltage and meet the requirements of EL lamp.A current comparator with enable signal is used in this paper to instead of error amplifier.Specific analysis and simulation results of the circuit are available in this paper.The circuit can achieve a response time about 25 μs,a reference current source about 4.3 μA,a load regulation rate about 6%,an output voltage from 70 V to 100 V,and this circuit can be applied to 19.4 cm2～38.7 cm2（3 in2～6 in2） EL Lamp.Above all,the circuit can act quickly,operate stably and be integrated conveniently.