In electronic products, we often see the figure of DC/DC, LDO, what are the differences between them, in the design of electronic products how to choose and how to design to avoid the defects of circuit design?
DC/DC is to convert a constant current input voltage into another constant current output voltage, the common types are Boost (Boost), Buck (Buck), up and down voltage and reverse phase structure.”Is the abbreviation of lowdropoutvoltageregulator, low dropout linear regulators.They both stabilize an input voltage to a certain voltage, and the LDO can only be used as a step-down output.In the selection of power chip mainly pay attention to the parameters:
1. Output voltage.DC/DC output voltage can be adjusted by feedback resistance, LDO has two types of fixed output and adjustable output;
2, input and output voltage difference.The voltage difference between input and output is an important parameter of LDO. The output current of LDO is equal to the input current. The smaller the pressure difference, the smaller the power consumption and the higher the efficiency of the chip.
3. Maximum output current.LDO usually has A maximum output current of several hundred mA, while DCDC has A maximum output current of several A or more.
4. Input voltage.Different chips have different input requirements.
5. Ripple/noise.The ripple/noise of DC/DC working in the switching state is worse than that of LDO, so the circuit that is more sensitive at design time should try to choose LDO power supply.
6. Efficiency.If the input and output voltage are close, the relative efficiency of choosing LDO is higher than DC/DC; if the pressure difference is large, the relative efficiency of choosing DC/DC is higher. Since the output current of LDO is basically the same as the input current, the voltage drop is too large and the energy consumed on LDO is too large, the efficiency is not high.
7. Cost and peripheral circuit.The cost of LDO is lower than that of DCDC, and the peripheral circuit is simple.
Post time: Mar-15-2022