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tps62736 - VIN_OK

Other Parts Discussed in Thread: TPS62736

I'm using a tps62736 and I want to use the VIN_OK to tell the MCU that the battery need to be charged or not. I'm using a LiPo (4.2v to 3.5v) and a Vout of 3V. The maximum high inout voltage on the MCU is Vdd+0.3 = 3.3V and only now I noticed I connected the VIN_OK to a MCU inout. I haven't used that particular MCU IO yet so I don't know if I blow it already or not but what should I do to connect it to MCU?

Is a voltage divider the only option? My circuit use 20uA when sleeping and it is most of the time, use a voltage divider will increase the consunption :s 

  • You should set the output of the TPS62736 to 3.3V and connect the regulated OUT on TPS62736 to power up your MCU.
    VIN_OK is an digital output to your MCU GPIO that indicates the input (your batter) voltage is at an acceptable level. VIN_OK pulls high when the input voltage rise above VIN_OK threshold+VIN_OK_HYST. VIN_OK pulls low when the input voltage drops below VIN_OK threshold. In your case, VIN_OK should be set to 3V or little bit higher to give more head room.
  • Sorry my poor english :s I'll try to explain myself better. I had set the TPS62763 to 3V as required by MCU and that is ok. I'm using a LiPo rechargeable battery so I don't want it to discharge above 3.5V and I have a circuit that does that. Now I want to tell the MCU that the battery level is above 3.6V so it can alert the user. The problem is that the VIN_OK is pulled to battery voltage so when the battery is charge (4.2V) VIN_OK will be 4.2V, right?

  • I measure the VIN_OK output and the multimeter read 3.0V the same of my Vout but the datasheet said: Push-pull digital output for power-good indicator for the input voltage.Pulled up to VIN pin.
  • yes, when VIN is above the VIN_OK + VIN_OK_HYST threshold, the VIN_OK output will be pulled to VIN. In your case, voltage on VIN_OK when it is pulled high should be 3.6V to 4.2V. Depending on the MCU pin rating, you might need to use a voltage divider circuit to reduce the VIN_OK signal voltage.