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Hello everyone, today we will learn about the generation process of the standby power supply

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PP3V3_G3H_RTC in the Apple A2159 circuit

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PP3V3_G3H_RTC is generated by TPS62180 control

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Let's search in the circuit

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This is a tiny PWM controller, which integrates two upper and lower tubes

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Among them, VIN1 provides power supply to the D-level of the first tube,

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and the phase pin of the first road is SW1

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The D-stage of the second tube is powered by VIN2,

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and the phase pin of the second road is SW2

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This power supply comes from the common point

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We trace the name of its external power supply and find its source,

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we found that it was renamed after the common point voltage passed through a current-sensing resistor

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to provide the main power supply for this U6903

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In addition to the power supply, this chip also needs to receive an open signal, EN

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This open signal comes from the CHGR_EN_MVR sent by the charging chip

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We searched for this EN and found that it comes from ISL9240,

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the internal name is EN_MVR, and the external name is CHG_EN_MVR

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With this open signal, it will control the work of the two upper and lower tubes,

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and generate two power supply outputs

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The back end of the inductor is connected together, and the PP3V3_G3H_RTC is generated by two PWMs

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and the PP3V3_G3H_RTC is generated by two PWMs

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This is a power supply with a maximum output current of 6A,

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and the operating frequency is 1.25MHz

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The external name is changed to PP3V3_G3H_RTC after the current-sensing resistor

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This is the first generation process of PP3V3_G3H_RTC

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let's review again

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The main power supply of PPBUS_G3H is what we talked about in the last lesson,

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it is generated by the control of the common point circuit PPBUS_G3H

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This common point should be returned to provide power to the PBUS_PWR pin of the charging chip

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The charging chip will send an EN signal to turn on the PP3V3_G3H_RTC

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After the power supply is generated,

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it mainly provides the main power supply for the U6940 and U7800 power chips

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Ok, this is the generation process of PP3V3_G3H_RTC power supply