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Hello everyone, today we will learn about Apple A2337 circuit timing analysis

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First, let's learn about the Type-C adapter boost PD protocol

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This lesson has two parts

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First, the definition of Type-C interface pins,

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second, the introduction of Type-C adapter boost PD protocol

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Let's first look at the pin definition of the Type-C interface

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The Type-C interface is on the top of the mainboard, which is called the "female head".

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It has A side and B side

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The pin definition of A side and B side is the same

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A side has 12 pins in total, from A1 to A12,

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B side also has 12 pins

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Let's take a look at the pins on A side first

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Pins A1 and A12 are both GND, ground pins

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Pins A2 and A3 are for signal transmission, one positive and one negative,

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which are differential signals and differential transmission

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A4 is VBUS power supply pin

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A5 is CC bus

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The CC bus is also called the configuration channel,

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which is used for the communication between the adapter and the mainboard

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This VBUS is used to transmit the adapter power supply

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Pins A6 and A7 are the buses of USB2.0

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A8 is the SBU pin, which is a custom bus,

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equivalent to the auxiliary channel AUX, customized by each manufacturer

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A9 is also VBUS power supply

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A10 and A11 are a pair of receiving signals and also differential transmission

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This pair of receiving signals and the previous pair of transmission signals are a set

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Ok, this is the pin definition for side A

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The pin definition of side B is the same

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Pins B1 and B12 are GND

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B4 and B9 pins are VBUS power supply

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B6 and B7 pins are common USB2.0 bus

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B5 is the CC bus, which is also called the configuration channel

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B8 is the SBU bus, equivalent to the AUX channel, which is customized by each manufacturer

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B2 and B3 are a pair of transmitting, B10 and B11 are a pair of receiving,

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both of which are used to transmit data

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Ok, this is the pin definition of the Type-C interface

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Let's take a look at the Type-C adapter boost PD protocol

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When the adapter is plugged into the laptop,

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the adapter will tell the laptop how many voltages and corresponding currents

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the adapter can provide through the CC bus

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After learning the power supply capability of the adapter,

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the laptop chooses a power supply method suitable for itself, and sends a request packet to the adapter

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The adapter evaluates its own capabilities according to the choice of the laptop

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and then sends the accept command

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Then the adapter performs voltage conversion internally and sends a "power ready" packet to the laptop

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The adapter will apply a new negotiated voltage to VBUS

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This is its boost flow

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If there is no CC bus communication, the adapter cannot boost the voltage

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Type-C adapters can provide a variety of power supplies, including 5V, 9V, 12V, 15V, 20V, etc.

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We can see from the waveform diagram below that

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the VBUS power supply is raised from 5V to 15V or higher after multiple communications on the CC bus

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If there is no CC bus communication, the VBUS power supply will not boost

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This boost process is done internally by the adapter

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Ok that's the boost protocol for the Type-C adapter