低压差线性电压调整器电源纹波抑制比测试方法

Power supply rejection ratio testing of low dropout linear regulator

低压差线性电压调整器应用广泛,电源纹波抑制比是反映其性能指标的关键参数之一。为解决传统电源纹波抑制比测试方法测量频率范围较小、测试效率低、难以满足高电源纹波抑制比测试等不足,提出基于功率分配器和低频网络分析仪相结合的电源纹波抑制比测试方法,并采用典型低压差线性电压调整器对基于功率分配器和基于电感电容总和节点法的两种测试方法进行测试验证。实验结果表明:基于功率分配器的电源纹波抑制比测试方法最低测试频率可达30 Hz,可满足70 d B以上电源纹波抑制比的测试需求,具有频率测量范围更宽、测试效率高等特点。

Low dropout linear regulator （LDO） has wide applications. As a key parameter of LDO, power supply rejection ratio （PSRR） determines the main performance. To overcome the drawback of low frequency band, low efficiency and non -ability to fulfill the high PSRR testing of traditional method, the testing method of PSRR based on power splitter and low frequency network analyzer is proposed. Typical LDO products are used to evaluate the proposed method based on power splitter and the traditional method based on the combination of inductance and capacitance. Experiment results show that the lowest test frequency of the PSRR testing method based on power splitter can reach 30Hz and it can meet the testing requirement of PSRR up to 70dB. Besides,it has a wide range of frequency and high efficiency.