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ldo [2016/06/02 19:35] gongyu [稳压] |
ldo [2016/06/02 19:41] gongyu [指标] |
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| ====指标==== | ====指标==== | ||
| - | An LDO is characterized by its drop-out voltage, quiescent current, load regulation, line regulation, maximum current (which is decided by the size of the pass transistor), speed (how fast it can respond as the load varies), voltage variations in the output because of sudden transients in the load current, output capacitor and its equivalent series resistance.[10] Speed is indicated by the rise time of the current at the output as it varies from 0 mA load current (no load) to the maximum load current. This is basically decided by the bandwidth of the error amplifier. It is also expected from an LDO to provide a quiet and stable output in all circumstances (example of possible perturbation could be: sudden change of the input voltage or output current). Stability analysis put in place some performance metrics to get such a behaviour and involve placing poles and zeros appropriately. Most of the time, there is a dominant pole that arise at low frequencies while other poles and zeros are pushed at high frequencies. | + | 评价一个LDO主要的指标有： |
| + | * 电压差 | ||
| + | * 静态电流 | ||
| + | * 负载调整率 | ||
| + | * 线调整率 | ||
| + | * 最大电流（取决于导通晶体管的大小） | ||
| + | * 对负载变化的响应速度 | ||
| + | * 由于负载电流的突变、输出电容以及等效的串行阻抗对输出电压的影响 | ||
| ====电源抑制比==== | ====电源抑制比==== | ||