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TPS2660: Could you tell me about TPS26600's ON/OFF control from microcomputer?

Pokkun
Genius 4695 points
Part Number: TPS2660

I'm planning to propose TPS26600 for the purpose of turning ON/OFF the 24 V line.

The ON-OFF signal is assumed to be input from the microcomputer.

Looking at the internal circuit of the data sheet, a pull-up resistor is built in the "/SHDN pin".

＜Question＞

When ON - OFF control is performed with a signal of a voltage different from the power supply voltage like a microcomputer, can it be controlled normally in this device?

I’m worried whether it's equivalent to the case below.(But it will my guess.)

· The sink current when the microcomputer output is L is small and the "/ SHDN" of this IC does not recognize L.

· If the microcomputer output is H, does the current flow from the VDD through this pin into the microcomputer to cause malfunction?

　etc ...

Best regards,

Masumi Sekiguchi

  • 0
    TI__Genius 16305 points
    Hi Masumi,

    Yes SHDNb pin can be controlled by an external microcontroller to turn on/off the TPS2660.

    Its threshold is 0.76V falling and 0.78V rising.
    SHDNb is pulled to 3.15V with 667Kohm internal pullup. (Figure 48 in datasheet)

    If the sink current from the microcontroller is atleast >10uA, then SHDNb voltage will be 0.4V worst case (refer to the electrical characteristics table).
    This will make the SHDNb less than worst case falling threshold 0.55V. That is 0.4V < 0.55V. So the device will shutdown.

    If the microcontroller is H, then current into micro controller is limited by the internal pull up resistor (667kohm).

    Regards,
    Kari.