Low Power Mode

Last Updated on : 2022-11-24 09:20:16download

This topic describes the common questions about the low power mode to help you troubleshoot problems.

Why is the operating current of BK7231T only 30 mA but the BK7231N module operates on 70 mA?

If the Wi-Fi module does not enter the sleep mode in an idle state, the power consumption will be high. You can make the module sleep except for the FFC and SoC mode.

Why does Wi-Fi use more power than other protocols?

This is because Wi-Fi consumes more power for emitting radio waves than other protocols.

What low power solutions do you provide?

  • Low power pairing

    If you enable the low power mode for device pairing, after a device is not paired within a specified time period such as 15 minutes, the Wi-Fi network will be turned off. You will find Wi-Fi status is 0 from the log output. The power reduction is achieved by turning off the Wi-Fi function. The actual power consumption is higher than using a low power chip.

  • Low power chip

    When a paired module is idle for a certain amount of time (depending on chip specifications), and I/O does not output signals, it will enter low power mode with a consumption of less than 0.2W.

    The low power on the Wi-Fi chip can be achieved by adjusting the Wi-Fi’s delivery traffic indication message (DTIM) interval or enabling the tickless low power mode of the CPU.

    Typically, the chip can operate in the sleep mode or the run mode. Chips with Arm® architecture can operate in the sleep mode, deep sleep mode, or run mode.

  • Power-off low power

    The approach to reducing the power consumption of some products such as locks and sensors is to control the on/off state of the Wi-Fi module. It is the serial protocol between the MCU and the module, not the hardware itself that makes the low power consumption possible.

What products does the low power mode apply to?

Wi-Fi door locks and sensors.

Why does the power consumption of the module fail to be reduced?

  • After power-on, the paired device will first resume its connection to the cloud before it can enter the sleep mode.
  • If a power outage occurs on the router, the power consumption of the device will become high even if it has been connected to the Wi-Fi network successfully.
  • Realtek registers some callbacks in the CPU pre-sleep handlers. If the callback returns failure and the CPU cannot enter the sleep mode, the power consumption will be high during pairing.

How does a low power chip work?

  • The principle to achieve low energy is that the module wakes up only when it has tasks to process and quickly enters the sleep mode after the task is completed.
  • You can increase the DTIM value to make the module sleep longer. The DTIM value ranges from 1 to 30, corresponding to the beacon interval from 100 ms to 3,000 ms.
  • The CPU operating mode and the DTIM value of the Wi-Fi module are the two major considerations for low power mode design.