内含稳定的瞬时备用电源的电源

以５Ｖ电源为例，阐述一种可以广泛应用于各种电子仪器的内含稳定的瞬时备用电源的电源的设计方法和元器件的选择。这种电源采用在两极稳压中间加瞬时备用电源，利用电源滤波电容上电压不能跳变，在电源突然掉电后滤波电容上的电压变化来控制开关元件，将备用电源接通和关断的原理设计。备用电源使用可充电电池。通过元器件的选择，可使这种电源在掉电后几十秒到百秒范围内不间断地向电子仪器提供稳定的电压，从而在小电流范围内可取代价格昂贵的ＵＰＳ电源。

A regulated power supply with instantaneous stand-by source

This paper describes the design and the elements selection of a regulated power supply with instantaneous stand-by source, taking 5V regulated power supply for example.It can be widely used in any kind of electronic instru-ment. The stand-by source which is a rechargeable battery is put in the circuit between two voltage regulators.The principle of this design is that using the changing voltage on the filter capacitor control the time of the stand-by source from on to off after the power supply dropped out, because the voltage on the filter capacitor cannot change suddenly.The power supplying time of the stand-by source can be from several seconds to a hundred seconds by using different el-ement.This kind of power supply can be used to replace the expensive UPS in small current.