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Suspend mode - bq2407x

Poh Leong Ng
Intellectual 745 points
Other Parts Discussed in Thread: BQ24070

Hello All,

What happend during suspend mode? Will the IC actively control the IN to OUT path or it simply shut off the charging path (Q1 is off)? Can I say that during suspend mode, IN is not connected to OUT? Will BAT supply the power to system or Q2 is off too?

Poh Leong

 

  • 0
    TI__Guru**** 150910 points

    I believe your question is answered on page 18 and 19 of the datasheet:

     

    Sleep and Standby Modes

    The bq24070/1 charger circuitry enters the low-power sleep mode if the input is removed from the circuit. This feature prevents draining the battery into the bq24070/1 during the absence of input supply. Note that in sleep mode, Q2 remains on (i.e., battery connected to the OUT pin) in order for the battery to continue supplying power to the system.

    The bq24070/1 enters the low-power standby mode if while input power is present, the CE input is low. In this suspend mode, internal power FET Q1 (see

    Figure 5) is turned off, the BAT input is used to power the system through the OUT pin. This feature is designed to limit the power drawn from the input supply (such as USB suspend mode).

     

    CE Input (Chip Enable)

    The CE (chip enable) digital input is used to disable or enable the IC. A high-level signal on this pin enables the chip, and a low-level signal disables the device and initiates the standby mode. The bq24070/1 enters the low-power standby mode when the CE input is low with input present. In this suspend mode, internal power FET Q1 (see block diagram) is turned off; the battery (BAT pin) is used to power the system via Q2 and the OUT pin. This feature is designed to limit the power drawn from the input supply (such as USB suspend mode).

     

    So, yes, in standby mode the input FET, Q1, is off and the output is supplied by the battery, through Q2.