1

00:00:00,166 --> 00:00:02,766

The working principle of the iphone standby circuit

2

00:00:03,000 --> 00:00:06,300

Here's a schematic block diagarm of the iPhone standby circuit

3

00:00:08,033 --> 00:00:10,700

The schematic block diagram is a simplification of some

4

00:00:10,700 --> 00:00:13,466

connection methods of the physical diagram

5

00:00:14,066 --> 00:00:16,466

which is easier for us to learn the principle

6

00:00:17,800 --> 00:00:20,100

The first step, when we buckle the battery

7

00:00:20,100 --> 00:00:22,300

or turn on the adjustable power supply,

8

00:00:23,400 --> 00:00:27,033

the positive pole of the power supply will be routed through the board layer

9

00:00:30,566 --> 00:00:33,333

The diode is integrated inside the charging tube

10

00:00:34,600 --> 00:00:37,366

The working condition of diode conduction is that

11

00:00:37,366 --> 00:00:40,766

the positive voltage must be greater than the negative voltage

12

00:00:42,133 --> 00:00:45,533

After we buckle the battery, the positive pole of the battery

13

00:00:45,533 --> 00:00:48,466

first reaches the positive pole of the diode

14

00:00:48,700 --> 00:00:51,633

At this point, the negative voltage is 0 volts

15

00:00:51,666 --> 00:00:53,333

when the diode is not conducting

16

00:00:53,500 --> 00:00:57,166

Therefore, the positive voltage is greater than the negative voltage,

17

00:00:57,466 --> 00:01:00,133

which satisfies the diode conduction condition

18

00:01:00,466 --> 00:01:02,900

Then the battery power will be converted to the

19

00:01:02,900 --> 00:01:04,500

rear stage through the charging tube

20

00:01:05,466 --> 00:01:08,400

The rear stage conversion is PP_VDD_MAIN,

21

00:01:08,566 --> 00:01:09,966

which is the main power supply

22

00:01:12,366 --> 00:01:15,566

The diode is also integrated inside the charging chip

23

00:01:16,233 --> 00:01:20,300

Therefore, the charging chip will also convert the main power supply voltage,

24

00:01:20,600 --> 00:01:23,600

and then send it to many components of the mainboard,

25

00:01:24,466 --> 00:01:26,400

including backlight circuit diode,

26

00:01:26,400 --> 00:01:29,200

receiver amplifier, speaker amplifier,

27

00:01:29,466 --> 00:01:31,433

vibration chip, boost chip,

28

00:01:31,500 --> 00:01:34,666

main power supply, wifi, etc.

29

00:01:37,633 --> 00:01:40,966

They'll all have voltage, after we plug the battery in

30

00:01:44,700 --> 00:01:47,733

So, are these chips already working at this time?

31

00:01:48,133 --> 00:01:49,633

No, they're not working yet,

32

00:01:49,666 --> 00:01:51,800

because other signals are needed

33

00:01:52,066 --> 00:01:54,066

Let's talk about the boost chip first

34

00:01:57,066 --> 00:01:59,900

The chip also integrates a diode inside

35

00:02:00,133 --> 00:02:03,033

The main power supply reaches the positive pole of the diode

36

00:02:04,000 --> 00:02:05,833

After the diode is turned on,

37

00:02:05,966 --> 00:02:09,666

the main power supply is converted to the power supply of the rear stage

38

00:02:10,200 --> 00:02:14,000

Then the power supply it converts is called PP_VDD_BOOST

39

00:02:14,433 --> 00:02:17,600

In addition to the boost chip, there are also vibration,

40

00:02:17,600 --> 00:02:20,466

speaker amplifier, and receiver amplifier

41

00:02:21,133 --> 00:02:23,033

These chips also integrate diodes

42

00:02:23,033 --> 00:02:25,266

and they can also convert power supply

43

00:02:27,000 --> 00:02:30,900

But the power supply they convert does not provide voltage for other chips,

44

00:02:31,333 --> 00:02:33,633

but prepares for future circuit work

45

00:02:39,366 --> 00:02:43,066

Then we see positions 1, 2, 3, and 3-1

46

00:02:45,266 --> 00:02:47,866

When we plug in the battery, all positions of

47

00:02:47,866 --> 00:02:50,466

1, 2, 3, and 3-1 will have voltage

48

00:02:51,233 --> 00:02:53,800

Among these lines, if a chip is damaged,

49

00:02:53,933 --> 00:02:56,133

or the filter capacitor is damaged,

50

00:02:56,566 --> 00:02:58,433

it will cause a short circuit

51

00:02:59,833 --> 00:03:02,000

If there are defective components,

52

00:03:02,133 --> 00:03:04,233

it will lead to electric leakage