As a hardware engineer, it is inevitable to deal with various chips. Today, we might as well talk about one of the "core" things for engineers: the choice of power chips. In PCB design, should the power chip choose DC/DC or LDO?

When designing the PCB, it is necessary to choose DC/DC or LDO for the power chip design. To put it simply, in boosting applications, of course, only DC/DC can be used, because LDO is a voltage drop type and cannot be boosted.

Selection of LDOs

When the designed circuit has the following requirements for the shunt power supply:

1. High noise and ripple suppression;

2. It occupies a small area of ​​the PCB board, such as hand-held electronic products such as mobile phones;

3. The circuit power supply is not allowed to use inductors, such as mobile phones;

4. The power supply needs to have instantaneous calibration and output status self-checking functions;

5. The voltage regulator is required to have a low voltage drop, and its own power consumption is low;

6. It is required that the line cost is low and the scheme is simple;

At this time, the choice of LDO is the most appropriate choice, while meeting various requirements of product design.

Furthermore, you need to look at the main features of each:

DC/DC: high efficiency and high noise; the advantage is that the conversion efficiency is high and can be large current, but the output interference is large and the volume is relatively large.

LDO: low noise, small quiescent current; small size, small interference, when the input and output voltage difference is large, the conversion efficiency is low.

Therefore, if it is used in the case of a relatively large voltage drop, choose DC/DC because of its high efficiency, and LDO will lose a large part of its efficiency due to the large voltage drop;

If the voltage drop is relatively small, choose LDO because of its low noise, clean power supply, simple peripheral circuit and low cost.

Summary: In general, when designing a PCB, it is necessary to choose DCDC for boosting; for bucking, whether to choose DCDC or LDO should be compared in terms of cost, efficiency, noise and performance.