Let%27s explore how microcontrollers (MCUs) handle low-power modes in detail:

1. Sleep Mode:
- Purpose: Sleep mode conserves power while allowing the MCU to wake up quickly when needed.
- Characteristics:
- CPU is halted: The CPU stops executing instructions.
- Peripheral clocks are active: Peripherals (like timers, UART) can continue functioning.
- Wakeup Sources:
- External interrupts, timers, or specific events trigger wakeup.
- Use Cases:
- Ideal for periodic tasks (e.g., sensor readings) with minimal CPU involvement.

2. Deep Sleep Mode:
- Purpose: Deeper power savings than sleep mode.
- Characteristics:
- CPU and peripherals are halted: All clocks are disabled.
- Wakeup Sources:
- External interrupts, RTC alarms, or specific events.
- Peripheral Deep Sleep Configuration:
- Some peripherals can remain active (e.g., RTC for timekeeping).
- Use Cases:
- Long idle periods (e.g., battery-powered devices).

3. Hibernate Mode:
- Purpose: Maximizes power savings during extended inactivity.
- Characteristics:
- CPU, peripherals, and RAM are powered off: Only a small portion of RAM retains data.
- Wakeup Sources:
- External interrupts or RTC alarms.
- Use Cases:
- Devices that need to wake up occasionally (e.g., remote controls).

4. Examples in Specific MCUs:
- PSoC 4 MCU:
- Offers various low-power modes, including sleep and deep sleep.
- Utilizes PSoC Creator power management functions.
- Example projects demonstrate low-power programming¹.
- PSoC 6 MCU:
- Features seven power modes, including low-power (LP), ultra-low-power (ULP), deep sleep, and hibernate.
- ARM® CPU modes (active, sleep, deep sleep) are available within LP and ULP modes²³.

In summary, MCUs employ different low-power modes to balance functionality and energy efficiency, ensuring optimal performance for various applications.


(1) PSoCTM 4 MCU low-power modes and power reduction techniques. https://www.infineon.com/dgdl/Infineon-AN86233_PSoC_4_and_PSoC_Analog_Coprocessor_LowPower_Modes_and_Power_Reduction_Techniques-ApplicationNotes-v09_00-EN.pdf?fileId=8ac78c8c7cdc391c017d0737cdb15b82.
(2) AN219528 PSoC™ 6 MCU low-power modes and power reduction techniques. https://documentation.infineon.com/html/psoc6/jql1667481395768.html.
(3) PSoC 6 MCU low-power modes and power reduction techniques. https://www.infineon.com/dgdl/Infineon-AN219528_PSoC_6_MCU_Low-Power_Modes_and_Power_Reduction_Techniques-ApplicationNotes-v05_00-EN.pdf?fileId=8ac78c8c7cdc391c017d0d31efdc659f.

icDirectory Limited | https://www.icdirectory.com/b/blog/how-do-mcus-handle-low-power-modes-sleep-standby-etc.html