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Small startup current of iPhone

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In this lesson, we will focus on the common terms explanations used in startup small current circuits

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There are several terms commonly used in startup small current circuit

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The first two terms we have learnt in the boot high current circuit

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LDO refers to the power supply output of small current,

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while BUCK refers to the power supply output of large current

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CLK refers to the clock signal and RESET refers to the reset signal

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In electronics, for a chip to work,

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it first needs power, clock signal and reset signal

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The clock signal refers to the frequency that electronic products need to work

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The higher the clock frequency, the faster the chip runs

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RESET is a reset signal

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When the chip is working, there is a reset signal

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It is mainly used to make the chip work from the beginning

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Without this reset signal, the chip may not work and may remain in its original state

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TEST_CLKOUT, this is the test clock output

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When the clock circuit is working properly,

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it will issue a test clock

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SYSTEM_COLD_RESET, this is a system-wide reset,

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in the iPhone it's a CPU reset signal

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The CPU also needs a reset signal for it to work

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So that's all for this lesson