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TS5A3160: TS5A3160 - not working - no output voltage

Dnyaneshvar s
Intellectual 521 points
Part Number: TS5A3160
Other Parts Discussed in Thread: CC2650

Hello,

We have designed a PCB with analog switch TS5A3160.

At output of analog switch Display is connected.

It was supposed that we will control the Display power using TS5A3160 switch and turn the display power OFF when not required to save coin cell battery life.

Our schematic is as shown in the Image.

I have written a simple GPIO toggling code in CC2650 microcontroller board

I have verified that

pin no 2 is at Ground - 0V

pin no 3 is NC and floating - not connected to anywhere.

pin no. 4 COMMON terminal is at 3.3v level

pin no. 5 V+ is at 3.3v terminal

Pin no. 6 is getting 0 and 3.3 volts when GPIO is toggled at 5 second interval.

pin no. 1 is NO (normally open).

when I give logic 1 at pin no. 6 ie IN terminal, I get 3.3v at Pin no. 1, but when I give logic 0 to IN pin, my output at pin no. 1 does not switches back to 0v.

It reduces till 3.0 volts only.

Q1-> Is the above schematic/design correct?

if NO then what should be the correct schematic to get the desired results?

Thank you

Dnyaneshvar salve

  • 0
    Guru 260500 points

    Is there any load connected to pin 1? If not, the pin is floating, and you cannot measure its voltage.

    If you want the disabled power supply to be at 0 V, connect pin 3 to GND. (To slowly discharge the power supply, use a resistor.)

  • 0 in reply to Clemens Ladisch
    Intellectual 521 points

    Hi Clemens Ladisch,

    Thank you very much the quick reply.

    Is there any load connected to pin 1? 

    pin no.1 is connected to VCC pin of display and one terminal of 10uh inductor which is part of display's boost convertor.

    If you want the disabled power supply to be at 0 V, connect pin 3 to GND. (To slowly discharge the power supply, use a resistor.)

    I tried connecting 150K ohms and 100K ohms from pin 3 to ground, but I am still getting 1.66V instead of 0V when IN is logic 0

  • 0 in reply to Dnyaneshvar s
    Intellectual 521 points

    I again tried with 47K ohms resistor from pin 3 to ground, but I am still getting 1.66V instead of 0V at OUTPUT terminal NO (normally open)

  • 0 in reply to Dnyaneshvar s
    Intellectual 521 points

    just realized that 1.66 is exactly half of 3.3V

    Any Idea what is wrong?

  • 0 in reply to Dnyaneshvar s
    Guru 260500 points

    This looks as if the display is powered from elsewhere, or as if the display has enough capacitance so that the voltage cannot discharge quickly.

    What voltage do you get at pin 1 if you disconnect the display?

    What happens when you use a much smaller resistor, like 100 Ω?

  • 0 in reply to Clemens Ladisch
    Intellectual 521 points

    This looks as if the display is powered from elsewhere,

    Display is being powered by analog switch output pin no .1 only.

    The Inductor mentioned is part of boost convertor, And only Input terminal of inductor is connected.

    What voltage do you get at pin 1 if you disconnect the display?

    I am toggling IN pin 6 at 10 sec interval

    10 sec logic high then 10 sec logic low

    when display is not connected and IN pin 6 is at logic low, voltage at pin no.1. starts to reduce till 2.99V from 3.30V.

    What happens when you use a much smaller resistor, like 100 Ω?

    I have connected 100 ohms resistor from pin no 3 to ground.

    Now I am getting 2.86V on pin no 1 (Normally Open) (with display connected)

  • 0 in reply to Dnyaneshvar s
    Guru 260500 points
    Dnyaneshvar s said:
    when display is not connected and IN pin 6 is at logic low, voltage at pin no.1. starts to reduce till 2.99V from 3.30V.

    Is this with or without the discharge resistor at pin 3?

    Now I am getting 2.86V on pin no 1 (Normally Open) (with display connected)

    I guess this is with pin 6 high? What happens when pin 6 is low?

  • 0 in reply to Dnyaneshvar s
    TI__Mastermind 25593 points

    Hey Dnyaneshvar,

    To add on to what Clemens has asked, is this only seen on one device? Have you tried swapping in a new device and seeing if the behavior persists?

    Thanks,
    Rami

  • 0 in reply to Rami Mooti1
    Intellectual 521 points

    Hi Rami Mooti1,

    is this only seen on one device? Have you tried swapping in a new device and seeing if the behavior persists?

    Yes, I tried with one more device. Same results.

    Now,

    I have done few changes to the circuitry now.

    I have disconnected the display and its inductor terminal from output terminal - pin no.1 of analog switch,

    connected 150K resistor from pin.no 1 to ground.

    I am getting 3.3V and 0V when IN pin is at toggled.

    Resistor connected from (NC-normally connected pin)pin no.3 to ground which was suggested by Clemens Ladisch is now removed. IC operation is not affected by this action.

    So is that resistor required? If yes then what should be calculations to select it's value?

    Can I get the reference design for TPS5A3160 and any basic design resource/Doc?

  • 0 in reply to Dnyaneshvar s
    Guru 260500 points

    Sorry; I misread the schematic. NC is never connected to NO, so the resistor has no effect on pin 1.

    To be able to discharge the display power, you would need to exchange the connections at pins 1 and 4.

  • 0 in reply to Clemens Ladisch
    Intellectual 521 points

    It's okay, No problem at all.

    To be able to discharge the display power, you would need to exchange the connections at pins 1 and 4.

    I not able to understand this.

    Can you please elaborate

  • 0 in reply to Dnyaneshvar s
    Guru 260500 points

    1. With the current circuit, when the control input is high, VDD is connected to the display, and when the control input is low, VDD is connected to NC and the display is connected to nothing.

    2. When you exchange pins 1 and 4, when the control input is high, VDD is connected to the display, and when the control input is low, NC is connected to the display and VDD is connected to nothing.

    If you want to discharge the display's power supply, you need to connect a pull-down resistor to the display, so you need case 2.

  • 0 in reply to Clemens Ladisch
    Intellectual 521 points

    Hi Clemens Ladisch,

    To stop the return voltage from display and Inductor side towards the analog switch, I have added one schottky diode which is creating the one way path and avoiding the return voltage from display side.

    I thank you, for the help you have provided to me.

    Dnyaneshvar Salve