Some mobile phones have the option to schedule switch-off time and switch-on time. Switch-off time is understandable. But how can a mobile switch itself on, if it was completely switched off?
Does this imply that, even when the mobile is switched off, the screen is off and the hardware buttons are not responsive, the mobile is never really switched off?
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> Does this imply that, even when the mobile is switched off, the screen is off and the hardware buttons are not responsive, the mobile is never really switched off?
Power management has actually gotten pretty complex. The following would be typical states that a modern smartphone might be in:
– **High performance**: the OS detected that some app is using a lot of processing power, so briefly boosts the CPU speed to help it. It can’t do this for too long because of power consumption and heat dissipation reasons.
– **Regular performance, fully on**: the normal state when the user is on the phone.
– **Idle**: user hasn’t touched it for a while, so let’s dim the screen and wait a bit longer.
– **Sleep/locked**: turn off the screen and power down the main CPU, leaving the baseband processor to periodically talk to the cellular network, and maybe a specialized low-power chip to listen for things like “Hey, Siri.”
– **Low power**: running low on battery, pause the routine maintenance tasks, cap CPU performance. Warn the user!
– **Charging overnight**: the user is probably sleeping, let’s take this time to do housekeeping tasks and maybe even download a software update or two.
– **Off**: everything off except minimal circuitry that can turn things back on if the user presses the power button.
So it really depends on the specific software design, but there generally is a “pretty-close-to-truly-off” state that uses very little power, even though phones don’t typically have a physical circuit-breaking switch that disconnects it from the battery.
> Does this imply that, even when the mobile is switched off, the screen is off and the hardware buttons are not responsive, the mobile is never really switched off?
Power management has actually gotten pretty complex. The following would be typical states that a modern smartphone might be in:
– **High performance**: the OS detected that some app is using a lot of processing power, so briefly boosts the CPU speed to help it. It can’t do this for too long because of power consumption and heat dissipation reasons.
– **Regular performance, fully on**: the normal state when the user is on the phone.
– **Idle**: user hasn’t touched it for a while, so let’s dim the screen and wait a bit longer.
– **Sleep/locked**: turn off the screen and power down the main CPU, leaving the baseband processor to periodically talk to the cellular network, and maybe a specialized low-power chip to listen for things like “Hey, Siri.”
– **Low power**: running low on battery, pause the routine maintenance tasks, cap CPU performance. Warn the user!
– **Charging overnight**: the user is probably sleeping, let’s take this time to do housekeeping tasks and maybe even download a software update or two.
– **Off**: everything off except minimal circuitry that can turn things back on if the user presses the power button.
So it really depends on the specific software design, but there generally is a “pretty-close-to-truly-off” state that uses very little power, even though phones don’t typically have a physical circuit-breaking switch that disconnects it from the battery.
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