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TRS3243E: Two device using the TPS3243 as Automatic Power Down can't communicate each other.

Part Number: TRS3243E

I'm sorry my poor English.

・own product = OP ※OP use TPS3243

・OP(TPS3243 as Automatic Power Down enable) : FORCEON = L / FORCEOFF = H

・OP(TPS3243 as Automatic Power Down Disable) : FORCEON = H / FORCEOFF = H



・OP(TPS3243 as Automatic Power Down enable)  -  <RS232C>  -  PC

・OP(TPS3243 as Automatic Power Down disable)  -  <RS232C>  -  OP(TPS3243 as Automatic Power Down enable)


・OP(TPS3243 as Automatic Power Down enable) - <RS232C> - OP(TPS3243 as Automatic Power Down enable)

If two device using the TPS3243 as Automatic Power Down can't communicate  each other, what should I do?

Best Regard

  • Hi,

    When TRS3243E is in auto-powerdown mode and the device does not sense a valid RS-232 signal, the driver outputs will be disabled. In your setup, both transceivers are likely disabling their drivers and therefore do not see a valid signal and remain powered down. This would effectively put the system in a low-power mode. To regain communication, one of the devices would have to have FORCEON go high to re-enable drivers. Once the receiving device recognizes the valid input, it may also have FORCEON enabled to respond. 

    1) Both devices are in low-power state. Drivers disabled 

    FON=L; FOFF=H              FON=L; FOFF=H

     OP1(TPS3243) ============= OP2(TPS3243)

     Power = OFF                Power = OFF


    2) Node 1 enables FORCEON to send message to Node 2

    FON=*H*; FOFF=H            FON=L; FOFF=H

     OP1(TPS3243) ============= OP2(TPS3243) 

     Power = ON                Power = OFF

    Send data  =>            => Receive data


    3) Receiving Node 2 enables FORCEON to respond to Node 1

    FON=H; FOFF=H              FON=*H*; FOFF=H

     OP1(TPS3243) ============= OP2(TPS3243)

     Power = ON                 Power = ON


    I hope this is clear. Let me know if you have any more questions or would like further clarification.



  • Mr. Eric Schott

    Thank you for your reply.

    I would like to refer your opinion.

    Best regard.