• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 65 subscribers
  • Views 627 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS2116: PSPICE simulation questions

Peter A
Intellectual 255 points
Part Number: TPS2116
Other Parts Discussed in Thread: TPS2115, TPS2113A, TPS2113,

Hi all, 

I am considering using two TPS2116 in series to create a switching mechanism between 3 power supplies. I want to switch between a barrel jack, USB and a off board header, with priority given to the barrel jack, followed by the USB followed by the header. 

I've been simulating the TPS2116 with the following circuit in PSpice with TI:

I am using the 5.1v on Vin2 simply to see which supply is being used but in reality both supplies should be 5V. As I understand, when PR1 drops below 1V, the supply will switch to Vin2, which it does. However it seems that as soon as Vin1 drops below 1V, thus meaning "MODE" is below 1V, the Vout goes to 0V. Please see the graph below. I have tied MODE to Vin1 for priority mode as instructed in section 7.6.1 of the datasheet which says: 

"When MODE is tied high, PR1 determines the channel selected. To configure VIN1 as the priority supply, connect MODE to VIN1 and set the proper threshold through a resistor divider from VIN1 to PR1."

Vin2 follows Vin1 (so Vin2 is ON when Vin2 while Vin1 is off). I also have tried it with Vin2 as a DC supply 

Pulse on Vin1 and Vin2



Pulse on Vin1, DC on Vin2



Note that when I tie Mode to Vin2 pulled high constantly, the device switches between the supplies without an issue. 


Q1: Is this behaviour expected or have I made a mistake or misunderstood the datasheet? - should Mode be constantly high for priority mode and not tied to Vin1? 
Q2: Do you have recommendations for the circuit component values to reduce the dip in Vout at switch over ? 
Q3: TPS2116 is out of stock at the main suppliers - Can you provide SPICE files for other devices such as the TPS2113A or the TPS2115? 

Thanks, 
Peter


  • +1
    TI__Genius 13300 points

    Hello Peter,

    When MODE is connected to VIN1 and you connect PR1 using a resistor divider to Vin1 it will work in priority mode. When PR1 goes below Vref the device will switch to Vin2. If MODE/Vin1/PR1 are all low Vin2 will be selected. The only situations in which Vout would be low or Hi-Z is if either PR1 is held high while MODE is low, or if you have invalid inputs. So you have it set up correctly.

    This seems to be an issue with the model. I will test this and submit a ticket to have this fixed. I would suggest trying this out using our EVMs.

    Regards,

    Kalin Burnside

  • 0 in reply to Kalin Burnside
    Intellectual 255 points

    Hi Kalin, 

    Thanks for the reply and confirming this.
    Are there any other SPICE models available for the TI power mux range? E.g. TPS 2115 or TPS2113? I couldn't find any others in the PSPICE for TI so just wanted to check if there were any more available? 

    Many thanks, 
    Peter

  • 0 in reply to Peter A
    TI__Mastermind 28745 points

    Peter,

    The best way to see the behavior of the part would be to order an EVM and use this for testing. From the application you described, TPS2116EVM would be the appropriate device to order for testing. Depending on the device, the PSPICE models might have varying behavior and the actual silicon will be the best way to test the device.

    Best Regards,
    Timothy Logan