S6BP501A/502A PMIC Under Cold-Cranking Conditions – KBA223770

Version 3

    Version: **

     

    Translation - Japanese: コールドクランキング条件下でのS6BP501A / 502A PMIC – KBA223770 - Community Translated (JA)

     

    Question:

    How to apply S6BP501A/502A under cold-cranking condition?

     

    Answer:

    Cold-cranking is the electrical condition that occurs when an automobile engine starter draws an excessive amount of current from battery due to increased torque needed to start an engine in cold temperatures. The battery voltage drops drastically for a moment due to the excessive current. The battery voltage profile under cold-crank condition specified in ISO16750-21 is shown in Fig.1.

     

    Fig.1 ISO16750-2 battery voltage profile for cold-cranking

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    Table.1 shows the Recommended Operating Condition of S6BP501A/502A. After starting up when the input voltage rises over 6.8 V, S6BP501A/502A can operate in the 2.5 V~42 V input voltage range. Therefore, the PMIC can meet the cold-cranking spec in Fig.1.

    However, following limitation need to be noted:

    §  In the 4.5 V–42 V input voltage range, the output voltage and maximum current spec of all three channels can be met under recommended temperature range.

    §  In the 3.7 V–4.5 V input voltage range, the output voltage and maximum current spec of all three channels can be met under Ta = +25°C condition.  (DD3V output voltage might drop at high temperature).

    §  In the 2.5 V–3.7 V input voltage range, the DD3V output voltage drops with the input voltage; VOUT5V can only supply up to 1 mA load current under Ta = +25°C and when VOUT1V and VOUT3V are disabled.

     

    Therefore, if the minimum of the system input voltage is in the 2.5 V–4.5 V range, the MCU should have the input voltage drop detection function to ensure correct system operation under cold-cranking condition. It is recommended to shift the MCU to the specific operation mode when the MCU detects input voltage drop to prevent MCU malfunction from output voltage drop of S6BP501A/502A.

     

    Furthermore, the period the input voltage is in the 2.5 V–4.5 V range must be within the spec of ISO16750-2 (Fig.1). Otherwise, S6BP501A/ 502A cannot be applied.

     

     

    Table.1 S6BP501A/502A Recommended Operating Condition