How to select the power chip? How do you see the power chip model?

In circuit design, there are no more than two commonly used power devices, DC/DC and LDO.

1. LDO is a low-dropout linear regulator, or low-dropout device, indicating that it is generally used in occasions where voltage reduction is required, and has the advantages of low cost, low noise, and low quiescent current. It also requires few external components, usually only one or two bypass capacitors.

The main reason why the performance of the LDO linear regulator can reach this level is that the pass transistor is a P-channel MOSFET. The P-channel MOSFET is voltage-driven and does not require current, so the current consumed by the device itself is greatly reduced. In addition, the voltage drop across the P-channel MOSFET is roughly equal to the product of the output current and the on-resistance. Since the on-resistance of the MOSFET is very small, the voltage drop across it is very low.

2. DC/DC means DC to (to) DC (conversion of different DC power values). As long as it meets this definition, it can be called a DC/DC converter, including LDO. But the general saying is that the device that converts DC to (to) DC by switching is called DC/DC.

DC/DC includes step-up, step-down, step-up/step-down, and reverse circuits. The advantages of DC/DC converters are high efficiency, high output current, and low quiescent current. With the increase in integration, many new DC/DC converters require only a few external inductors and filter capacitors. However, the output pulsation and switching noise of this type of power controller are relatively high, and the cost is relatively high.

How to select the power chip

If the input voltage is very close to the output voltage, it is best to use an LDO regulator, which can achieve high efficiency, and most importantly, low cost. Some experts in the industry have summarized the applicable LDO applications:

For example, products that require high-demand power supply noise suppression and ripple suppression,

For example, the PCB area is small, such as handheld electronic products such as mobile phones,

For example, the circuit power supply does not allow inductors, such as mobile phones and other products,

For example, the power supply needs to have instantaneous calibration and output state self-checking functions,

For example, products that require low voltage drop in voltage regulators and low power consumption,

For example, products that require low line costs and simple solutions.

If the input voltage and the output voltage are very different, or the voltage drop is large, you should consider switching DC/DC, because the input current of the LDO is basically equal to the output current. If the voltage drop is too large, the LDO will be consumed. The upper energy is too large and the efficiency is not high, so DC/DC is very suitable. Although DC/DC has high efficiency and can output large currents, at the same time, the output interference is relatively large, the volume is relatively large, and the cost is slightly higher.

In summary, DC/DC must be selected when boosting, and DC/DC or LDO should be selected for step-down. It is necessary to compare and analyze the cost, efficiency, noise and performance.

To buy a power chip, in addition to choosing the right type of brand, you must also choose the right type of power chip model according to the actual functional requirements and application areas. Because there are so many types of power chip brands and models, many people are usually confused when they buy. They don’t know how to select them, or even don’t even know how to look at the power chip models. It is recommended that you understand the following contents so that you can have some choices when choosing Better advantage.

Key points of power chip selection

1. Understand the characteristics of power chip models

It’s actually very simple to look at the power chip model. You just need to understand the different brand types, the characteristics of the power chip, especially the specific characteristics of the power chip of this model, so that you can judge the power chip model by some features, and you can have more details when you choose to buy it. Targeted standards.

2, judge through the package instructions

If you don’t know the specific model of the power chip you bought, there is no way to determine the power chip. The specific model can be judged directly from various materials such as packaging or manuals, or you can directly consult the merchant to know the power chip you bought What type of model is it? Then we can determine the specific function and application scope of the power chip of this model, and determine whether it meets your application requirements.

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