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Hello everyone, we watched the generation of 1.8V power supply in the last class,

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and we looked at the generation of 0.75V bus power supply according to the timing

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We open the drawing and find the 0.75V bus power supply in the catalog

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Jump to its circuit generation page

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After finding the 0.75V generating circuit, observe the circuit

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It can be seen that it is also a PWM circuit

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And the power supply chip used by 0.75V is the same as that of 1.8V

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Then we'll look for his power supply and turn-on signal too.

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The power supply is also the same from the gold finger 12V

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let's draw it first

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Let's look at the open signal

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The turn-on signal is the same as that of 1.8V, controlled by two N-channel MOS transistors

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Moreover, the enable signal cannot be directly pulled up to high

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The turn-on signal must be high level, then it must be cut off here

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Then it must be low level here, and the front MOS tube will be turned on.

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Here should be high level

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This high level signal is called 0.75V_EN

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Let's find out where the high level of 0.75V_EN comes from

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It can be seen that 0.75V_EN is directly converted from 1.8V_POW_GOOD

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And 1.8V_POW_GOOD has been generated in the last lesson, so the 0.75V EN signal has also been generated

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Let's draw this part as well

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With the power supply and enable signal, a 0.75V power supply and a 0.75V PG signal will be generated

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Well, so far, 0.75V has been generated normally