1

00:00:00,566 --> 00:00:05,333

This lesson talks about which circuits are related to the camera failure

2

00:00:06,066 --> 00:00:08,633

Look at the early models first

3

00:00:10,266 --> 00:00:15,266

The 1.8 volts power supply of the camera is issued by the power supply

4

00:00:15,600 --> 00:00:21,866

Next, the CPU detects the camera, and the CPU gives the camera a clock signal

5

00:00:23,400 --> 00:00:26,666

Then the CPU goes to reset the camera

6

00:00:28,066 --> 00:00:31,933

When we turn on the camera, these two LDO modules start to work,

7

00:00:32,000 --> 00:00:37,100

outputting 2.8 volts and 1.05 volts of power to the camera

8

00:00:38,533 --> 00:00:44,966

After the camera works, the image data is transmitted to the CPU through the MIPI bus

9

00:00:45,566 --> 00:00:48,633

This is the workflow of the camera circuit

10

00:00:49,366 --> 00:00:55,466

In this circuit, the camera is usually powered by the power supply or the LDO module

11

00:00:59,500 --> 00:01:05,033

The CPU detects the camera, sends a clock signal and a reset signal to the camera,

12

00:01:05,733 --> 00:01:10,966

and at the same time accepts and processes the image data transmitted by the camera

13

00:01:12,900 --> 00:01:19,433

So in this circuit, the camera, the camera connector, the power chip, the LDO chip and the CPU,

14

00:01:20,466 --> 00:01:24,000

only these components are related to the failure of the camera,

15

00:01:24,833 --> 00:01:28,933

and only these 5 components will cause the camera to fail to open

16

00:01:29,600 --> 00:01:32,900

This is the camera circuit of the early models

17

00:01:33,833 --> 00:01:39,000

Next, let's take a look at the camera circuit of mid-to-high-end mobile phones

18

00:01:40,366 --> 00:01:44,500

The camera has the power supply provided by the camera power supply

19

00:01:44,500 --> 00:01:48,666

and the power supply output after the step-down of the LDO module

20

00:01:49,133 --> 00:01:53,266

CPU sends clock signal and reset signal to camera

21

00:01:53,833 --> 00:01:58,033

The CPU detects the camera through the I2C bus

22

00:01:58,566 --> 00:02:05,166

After the camera works, the image signal is transmitted to the CPU through the MIPI bus

23

00:02:05,733 --> 00:02:08,766

In this circuit, the camera cannot be turned on,

24

00:02:09,200 --> 00:02:15,300

and the associated components include camera power, LDO module, and CPU

25

00:02:16,500 --> 00:02:20,400

The camera power supply mainly provides power supply

26

00:02:21,033 --> 00:02:24,966

Its damage will cause the power supply to fail to output normally,

27

00:02:25,233 --> 00:02:27,833

which will cause the camera to fail to open

28

00:02:28,233 --> 00:02:30,600

The LDO module is a step-down chip,

29

00:02:30,666 --> 00:02:36,766

usually it steps down the main power supply and outputs 2.8 volts to supply power to the camera

30

00:02:37,800 --> 00:02:43,100

Damage to the LDO module will result in no output of 2.8 volts

31

00:02:44,466 --> 00:02:50,100

If the camera cannot get this 2.8 volt power supply, the camera will not turn on

32

00:02:50,800 --> 00:02:57,000

CPU mainly provides I2C bus clock, reset signal and image transmission line

33

00:02:58,800 --> 00:03:03,300

If there is a problem with any of the lines, the camera will not work

34

00:03:05,400 --> 00:03:10,966

When a fault occurs, the fault is nothing more than a short circuit or an open circuit

35

00:03:11,933 --> 00:03:13,833

That's all for this lesson