Information About Low Dropout Regulators
Low Dropout Regulators or LDO Regulators are DC voltage regulators which function when the difference between input and output voltage is very less. These regulators are mainly made of components like FET and a differential amplifier or error amplifier. National Semiconductors first introduced the concept of low dropout regulators in one of their articles written in 1977 by one of their IC Engineers Robert Dobkin. The low- dropout regulator is different from a standard linear one. This regulator has only one PNP transistor. That is why as mentioned earlier the voltage change or drop required is very small that of a single PNP transistor.
The dropout voltage in this regulator is dependant on the load current directly. Thus amongst all types of voltage regulators, this one has the best and most feasible dropout voltage. That is why Low-Dropout Regulator are preferred and highly used in all applications that require batteries. They have the highest efficiency and use the input signal to its maximum capability. Thus in recent years since the use of battery operated devices has increased so the use of LDO regulators has also gone up. There are many types of low dropout regulators available today. There are single, double and triple Ldo regulators. Specific types are regulators like LP 2953 LDO, LM 2940 LDO regulators and many others.