The power supply can be divided into linear power supply and switching power supply. The linear power supply mainly uses LDO and the switching power supply uses DCDC. Linear power supply cannot be compared with LDO power supply.LDO power supply is only one of them.
LDO is a linear DC regulated power supply and DCDC is a switch ing DC regulated power supply. Their voltage regulation mechanisms are different.
The linear power supply (LDO) keeps the output voltage stable by adjusting the impedance change. When the output voltage rises due to the increase of input voltage or load current, the output voltage deviates from the set value and rises. The impedance of the regulating tube increases and the output voltage decreases to restore the set value and maintain stability.
When the input voltage decreases or the load current increases, and the output voltage deviates from the set value, the impedance of the regulating tube decreases due to negative feedback, and the output voltage increases to restore the set value and remain unchanged and stable.
DC DC converter is generally composed of control chip, pole coil, diode, triode and capacitor. It is a voltage converter that can effectively output fixed voltage. The input voltage is converted. It is mainly divided into step-up type, step-down type and step-down type.
Three control modes can be used as required. PWM control type has high efficiency and good output voltage ripple and noise. PFM control type has the advantage of low power consumption even if it is used for a long time. PFM control is realized during PWM / PFM conversion type small load, and automatically switches to PWM control in case of heavy load.
