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LDOs aka low-dropout voltage regulators are used to stabilize voltage. They are used to regulate the output voltage when the input voltage is too high or when the input voltage is close to the output voltage. LDOs have a very low voltage voltage drop when outputting a regulated voltage. This allows LDOs to be used in applications where the input voltage is close to the required regulated output voltage.
INTERVIEW QUESTION: What is the efficiency of an LDO/linear regulator?
Efficiency = Output Voltage / Input Voltage
How do LDOs work?
LDOs use a closed feedback loop to bias a pass element to maintain a constant voltage.
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