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Hello everyone, in this lesson we will learn the common power supply methods in the circuit

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There are generally three common power supply methods in the circuit, namely, switch mode,

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LDO mode and PWM mode.

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The switch method is the simplest power supply method

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It is characterized in that the input voltage is equal to the output voltage

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For example, the circuit on the right

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Its input voltage is 5V and its output voltage is also 5V

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So why bother to design such a circuit instead of connecting the power supply directly?

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That's because, using the switch mode can reduce the standby power consumption of the circuit

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Just like when we don't use a certain electrical appliance for a long time, we will unplug it

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When the rear equipment is not in use, turn off their power supply, which can reduce power consumption

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The second power supply method is the LDO method

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The characteristic of the LDO method is that the input voltage is not equal to the output voltage,

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and there are chips without inductors

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For example, the right picture, this is a LDO power supply method

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Its input voltage is 5V and its output voltage is 3V

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It can be seen that its circuit structure is very simple,

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and the voltage conversion can be easily completed

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However, its output power is generally relatively small

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and can only be used in circuits with very low power consumption.

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Finally, let's look at the PWM power supply method

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The PWM power supply method is similar to the LDO method.

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The input voltage is not equal to the output voltage, and the voltage conversion can also be completed.

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Moreover, compared with the LDO power supply mode,

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the output power of the PWM power supply mode will be much larger.

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However, the PWM power supply method also has disadvantages.

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Its disadvantage is that the circuit structure is very complex,

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generally composed of chips, inductors and other components

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For example, as shown on the right, this is a PWM power supply method

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Its input voltage is 3V and its output voltage is 0.9V,

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and there is an inductor

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Its circuit is more complicated than that of LDO