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Hello everyone, today we continue to learn the pin definition of the memory power supply chip

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of the Wistron 15221 motherboard.

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Let's first look at the pin definition of the memory power supply chip

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We open the circuit diagram and find the power supply chip PU5105

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This is the 2.5V power supply chip

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The VIN pin of this chip comes from the common point voltage 19V

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The name comes from the 19V_DCBATOUT renaming

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Then come to the 2, 3, 4, 5 pins of this PU5105 to provide power supply

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This is the power supply of the upper tube D pole inside the chip

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Because this chip integrates the upper and lower tubes

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Second, this chip needs working voltage

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BYP pin is its working voltage, provided by 3D3V_S5

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This VCC is the internal power supply of the chip, and there is no external power supply source

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This BS is the bootstrap presser foot

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PG means power good signal

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EN is open, ILMT is the limit current setting

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FB is Feedback

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GND is the ground, and it is also the S pole of the internal lower tube

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NC means empty pin

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LX is the phase pin, which is connected to the inductor at the output end

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Generally, this chip is powered, and after receiving the turn-on signal,

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it will control the internal upper and lower tubes to conduct in turn according to the set current

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to generate power supply output.

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Ok, this is the pin definition of this 2.5V power supply chip

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Next, let's take a look at the pin definition of the PU5101 chip.

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Search for PU5101 directly

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This chip can be divided into two parts, namely the LDO part and the PWM part

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This VDD is the power supply pin, usually provided by the 5V standby power supply

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This VID is the reference voltage setting of the FB pin

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When this pin is high, the internal reference of FB is set to 0.675V

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When this pin is low, the internal reference of FB is set to 0.75V

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CS pin is the limit current setting pin

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The PG pin is the power good signal output

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TON refers to the frequency setting

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The S5 pin is VDDQ EN, which can also be called the main power supply of the memory.

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S3 pin is LDO open, it can also be said that the memory VTT power supply is open

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VLDOIN This is the power supply of the LDO module, usually provided by the memory main power supply

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VTTGND This is the ground pin

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This VTT is the LDO output, which is the bus-powered output pin of the memory.

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VTTSNS is a voltage detection input pin, used to detect whether the VTT power supply is normal

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GND is the ground pin

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This VTTREF is the reference voltage output, which is generally not used in external circuits.

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FB is the feedback adjustment pin of the PWM part

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to detect whether the output end is overvoltage or undervoltage

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Generally, the output voltage at the rear end of the inductor is divided in series by a resistor.

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Back to the FB pin for feedback regulation of the output voltage

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This VDDQ is directly connected to the rear end of the inductor

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Equivalent to the VOUT pin of other PWM chips

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PGND and phase pin constitute the current detection circuit

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Connect the D pole and S pole of the lower tube through the phase pin and the PGND pin

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Detect the voltage difference between D and S after the lower tube is turned on to judge its output current

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The LGATE and UGATE are the upper tube drive and the lower tube drive pins respectively.

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The BOOT pin is connected to the bootstrap boost capacitor, this is the bootstrap boost pin

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Ok, this is the pin definition of the chip RT8231A