Handheld device Endurance

Handheld devices, such as tablets, e-books, and mobile phones, are similar in terms of endurance,

Take iPhone as an Example

Theoretical call time	480 minutes
Theoretical standby time	250 hours
Other use time	Music playback time: 24 hours Video Playback time: 7 hours Network Time: 6 hours

HTC Touch HD

Battery Capacity	1350 MAH
Theoretical call time	390 minutes
Theoretical standby time	450 hours

The call time parameter is available only on the mobile phone and only on the Internet.

Among them, the more common three parameters: standby time music playing time and video playing time, endurance is directly related to user experience, as an engineer, I think it is also possible to think about the demand from the perspective of the consumer's device users. Perhaps some consumers are most concerned about how long the video music can be played and how long the Internet can last without charging every day, or business people do not like considerations such as traveling with a charger.

After understanding this, we should be able to recognize the significance and importance of extended endurance, without exaggerating the potential impact on sales. How can we increase these parameters during R & D?

Theoretical call time

Although the power consumption has a very large and direct relationship with the internal chip design of the processor, as a software engineer, it can only be optimized on the basis of the existing platform, and its own parameters can be better.

The call time parameter is obviously the most basic parameter of the mobile phone and is very important. Although mid can also be used for network calls, its universality is not very high, and the demand is not as strong as the mobile phone. Here we only talk about the phone call time.

I personally think that development should be able to constantly analyze the needs from the perspective of application and R & D. Generally, calls do not need to be highlighted. Most of the usage cases are that users do not need to be highlighted at all, therefore, at this time, the entire system is allowed to run in a low-power State to maintain the call function of the signal. During R & D, you need to think about closing as many devices as possible, and the call time will be extended.

Theoretical standby time

The importance of the standby mode is highlighted by the long switching time. Imagine if you can quickly switch the host, there is no need to wait for this function. The chip has a standby status and a poweroff status.

The standby parameters are common and important and highly useful. For a mobile phone, the call time basically means how long it will take for you to power up the phone. So how can we achieve low standby power consumption? How can we quickly wake up on standby?

Roughly speaking, the Standby process is to put all hardware components into the "standby" state, without power loss, but maintain low power, and then wait for the wake-up state.

Music playback time

Some engineers may think that there is no need to use mid to listen to music, but mobile phone developers should be clear that using mobile phones to listen to music is a common habit of consumers. Therefore, reducing the power consumption of black screen playing music is practical and necessary.

Black screen music playback power consumption is theoretically Standby Power Consumption + Audio Subsystem Power Consumption

Video Playback time

Network usage time

The two parameters basically require the screen-on-screen operation. In terms of power consumption, the entire machine is required to work and the optimization space is small. Moreover, the ink bottle devices do not support videos and networks.

After introducing the power consumption parameters of several usage cases, there is a lot of room for optimization for playing music on the black screen. If you are familiar with audio drivers, you should understand that the Audio Codec Chip does not require the CPU to continue working, three conditions are required for playing music: Sound Card, clock, and serial data. After the audio sub-system is maintained, the CPU can be in the same low-power status as the standby mode, which greatly reduces the playback power consumption and prolongs the parameters of the playing time.

Ing ......