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TPS22916: TPS22916CN

Andy Chau
Prodigy 10 points
Part Number: TPS22916
Other Parts Discussed in Thread: TPS22914

Hi,

I want to design a circuit for battery charge and solid switch for system turn on/off,

1. when without USB_5V, than user use solid switch to on/off system.

2. when solid switch off, and user plugin USB_5V, than there has a charging current(4.2V/45mA) from V_system and through Load switch Vout to Vin and to Battery positive terminal.

The design purpose is for even solid switch =off , user sitll can through load switch to charge product.

My question as below:

1. Due to TP22916 has always on reverse current blocking function, is mean V_system current can't through Vout to Vin? If the answer is yes, is mean when i change Vout and Vin direction can solve this issue?

Note: when USB_5V exist , only has charge function , system other funtion will disable.

2. Is possible to use TPS22914B also? VIN connect to battery positive and Vout connect to V_system, when USB 5V plugin, through 22914 internal mos body diode  to charge battery, but there has a concern point, if the battery protector is lock mode(sys gnd and battery gnd disconnection), it's mean VIN(battery+)=floating, in this situation, if EN=5V ; VIN=Floating, the MOS body diode still can work?

Thank you

BR

Andy

  • +1
    TI__Mastermind 28090 points

    Hi Andy,

    Welcome to e2e!

    It is not recommended to rely on the body diode to conduct a systematic, purposeful current, as the body diode limits are not guaranteed by the data sheet.

    1. The TPS22916 reverse current blocking function activates when the current from VOUT to VIN is greater than 500mA (typ). A 45mA charging current shouldn't activate this feature. If the device is reversed, then when the system is off, 500mA of current will flow from the battery to the system, then the reverse current blocking feature will activate in 10us (typ). It looks like the TPS22916 enable functionality would only be useful when VIN is connected to V_system.

    2. In this scenario, would VIN be floating then? It's not recommended to use TPS22914 because it does not have any reverse current protection, and the body diode does not have tested specifications in the data sheet.

    Thanks,

    Patrick

  • 0 in reply to Patrick Shalton
    Prodigy 10 points

    Hi Patrick,

    Understood, thanks for your help~