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Hello everyone, today let's learn the LDO power supply mode

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of charging chip and standby chip output

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In this lesson, we will introduce two chips,

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one is the charging chip, the other is the standby chip

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Let's first take a look at the LDO of charging chip

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For example, U8800A,

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its model is BQ24725,

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and its REGN pin is the LDO output pin

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According to the information provided in the chip data book,

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pin 16 REGN is a linear regulator output

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REGN can output 6V linear, its power supply is from the VCC

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The VCC voltage must be greater than 6.5V,

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and the ACDET pin must have a voltage greater than 0.6V

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Then REGN can output 6 volts of linear, minimum 5.5V, maximum 6.5V

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At the linear output, a 1uF ceramic capacitor needs to be connected, grounded from the REGN pin

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In the actual circuit, this is the capacitor C8812

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Each linear output terminal is connected with a filter capacitor to ensure that its output voltage is more stable

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The basic process of how this chip works

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First it has to get VCC power

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Second, the ACDET pin needs to get a high level,

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and then the REGN will be generated

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This is a linear voltage generation process

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Next, let's take a look at the LDO output from the standby chip

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For example, this RT6575D, RT6575C

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It is a very common standby power supply chip in laptops

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The LDO3 pin of this chip is the 3.3V LDO output pin,

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and the LDO5 pin is the 5V LDO output pin

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The chip's workflow is simple

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It produces two linear outputs, LDO3 and LDO5, as long as it is powered

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The power supply is this VIN

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In addition to standby power supply chips and charging chips that can generate LDO linear output by themselves,

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there are many chips in the circuit that can generate LDO linear output by themselves,

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such as memory power supply chips and so on

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All right, that's it for this lesson