1

00:00:00,666 --> 00:00:02,300

iPhone trigger circuit

2

00:00:02,933 --> 00:00:08,033

In this lesson, we will mainly analyze the trigger circuit in the circuit diagram

3

00:00:08,433 --> 00:00:11,033

Take the iPhone XS model as an example

4

00:00:11,700 --> 00:00:12,966

In the circuit diagram,

5

00:00:13,066 --> 00:00:16,300

as long as the main power supply receives the main power supply,

6

00:00:16,533 --> 00:00:20,366

it will generate standby power supply PP1V8_ALWAYS

7

00:00:20,766 --> 00:00:24,100

Now let's look for the standby power supply in the circuit diagram

8

00:00:25,333 --> 00:00:29,866

We open the iPhone XS circuit diagram, component map and bitmap

9

00:00:31,366 --> 00:00:35,233

Search PP1V8_ALWAYS directly in the circuit diagram

10

00:00:36,466 --> 00:00:38,200

According to the circuit diagram,

11

00:00:38,500 --> 00:00:41,800

we know that the power supply is output by the main power supply,

12

00:00:42,133 --> 00:00:45,066

so we need to find the main power supply when we search

13

00:00:46,233 --> 00:00:49,366

The U2700 is the main power supply

14

00:00:50,366 --> 00:00:53,200

If you don't know, you can look at the component map,

15

00:00:53,400 --> 00:00:57,366

U2700, which corresponds to the main power supply

16

00:00:58,233 --> 00:01:00,800

This power supply we can view in the bitmap

17

00:01:02,600 --> 00:01:04,566

After the power supply is output,

18

00:01:05,600 --> 00:01:09,000

it does not provide operating voltage for other components

19

00:01:10,033 --> 00:01:13,066

After the standby power supply search is completed,

20

00:01:13,200 --> 00:01:17,000

let's look for the switch signal from the switch pin to the main power supply

21

00:01:17,600 --> 00:01:20,766

and the switch signal from the main power supply to the CPU

22

00:01:23,366 --> 00:01:26,966

First, open the component map and locate the switch seat

23

00:01:27,666 --> 00:01:30,433

According to the position number of the switch seat,

24

00:01:30,566 --> 00:01:33,333

we will search the switch position number in the drawing

25

00:01:34,533 --> 00:01:36,566

Locate the switch position number,

26

00:01:37,333 --> 00:01:40,033

according to the seat pin English identifier

27

00:01:40,333 --> 00:01:44,900

the iPhone 7- XSMax switch identifier is BUTTON_POWER_KEY

28

00:01:45,500 --> 00:01:48,633

The second pin in the circuit diagram is the switch pin,

29

00:01:50,066 --> 00:01:54,333

and the switch pin signal will be directly connected to the main power supply

30

00:01:55,200 --> 00:01:58,733

Let's see if it goes through other components in the drawing

31

00:01:59,766 --> 00:02:01,900

In the drawing we search for the switch pin

32

00:02:05,333 --> 00:02:11,533

After searching, we can see that the switch pin signal is connected to DZ4310,

33

00:02:12,866 --> 00:02:16,933

which is an anti-static diode and plays a protective role

34

00:02:18,900 --> 00:02:22,500

It is connected to the resistor R4310,

35

00:02:23,300 --> 00:02:25,766

which belongs to the protection resistor

36

00:02:28,033 --> 00:02:33,433

After passing the resistor it is connected to a capacitor C4310

37

00:02:33,833 --> 00:02:36,800

We search for the English name after the resistor

38

00:02:37,100 --> 00:02:41,300

In the search process, the same name means the same signal

39

00:02:42,600 --> 00:02:46,933

The name of the signal is the same, on behalf of the boot signal

40

00:02:48,066 --> 00:02:53,300

The power-on signal is connected to pin J14 of the U2700,

41

00:02:54,633 --> 00:02:56,900

which refers to the main power supply

42

00:02:59,433 --> 00:03:01,333

According to the circuit diagram,

43

00:03:01,500 --> 00:03:04,700

after the switch pin signal reaches the main power supply,

44

00:03:05,200 --> 00:03:08,666

the main power supply converts the switch signal to the CPU

45

00:03:09,466 --> 00:03:11,800

The conversion circuit is at the point

46

00:03:11,800 --> 00:03:14,866

where the switch pin signal reaches the power supply

47

00:03:18,233 --> 00:03:21,600

The switch pin connected to the power supply is BUTTON2

48

00:03:23,366 --> 00:03:27,900

This identifier is PMU_TO_AP_BUTTON_POWER_KEY

49

00:03:28,533 --> 00:03:32,300

This is the switch signal from the main power to the CPU

50

00:03:33,600 --> 00:03:36,200

We can view the connection through the dots

51

00:03:37,466 --> 00:03:41,733

This signal is directly connected from the main power supply to the CPU

52

00:03:42,333 --> 00:03:46,700

We can look for signals in the same way for iPhone 7 and older models

53

00:03:48,100 --> 00:03:50,033

So that's it for this lesson