• Resolved

TS5A3154: High current consumption

Expert 1025 points
user4725373

Part Number: TS5A3154

Hi,

I have this circuit that I've found consumes 20 mA where it should consume 1-2 uA.

  • CONN_DETECT, CONN_VIN1, CONN_VIN2 are floating
  • Vcc = 3.3V
  • P1 is a header that I can short two pins together

When the P1 connector's P$2 pin = Vcc, there is an increase of 10 mA. I removed U2 and U3 and there was a decrease in current consumption of 20 mA. I've seen an E2E thread where the user was powering a switch with 10V, but controlling it with a 3.3V signal. Here, the switches are powered with 5.6V and controlled with 3.3V. Would that be the problem? The datasheet says that 2.4V < VIH < 5.5V, so it should be good.

Thank you,

Fred

Expert 1025 points
user4725373
  • Mastermind 35665 points
    Adam Torma

    Fred,

    Please see note 2 from the TS5A3154 datasheet.  If the digital control logic signals are floating or not at V+ or ground there will be excess current consumption through Icc.  If you place the logic at Vcc of the switch does this fix the issue?

    More information can be found in the application note.

    Thank you,

    Adam

  • Expert 1025 points
    user4725373

    In reply to Adam Torma:

    Hi Adam,

    Thanks for the answer. The control pins (EN, IN) are already either Vcc or GND, so that wouldn't be the case. As mentioned in my previous post, P1 is a header in which I'll short the P$2 pin either to Vcc or GND.
  • Mastermind 35665 points
    Adam Torma

    In reply to user4725373:

    Fred,

    Sorry for my confusion. I meant to ask what is the result if you control the IN and EN pins with the same voltage you are supplying to the switch IC.

    In the schematic above I'm interpreting that the switch supply voltage is a 5.6 V and the IN and EN pins are at 3.3V. Since 3.3V is not at the same level as the "Vcc of the switch 5.6V" I would expect some extra current consumption. Does the current consumption improve if you set the IN and EN pins to 5.6 V?

    If that doesn't explain the extra current, the next place I would look is U2 connection C2 to A1. It might be possible that signal path is connecting Vcc to CONN_VIN1 that could be connect to something drawing the extra current.

    Thank you,
    Adam
  • Expert 1025 points
    user4725373

    In reply to Adam Torma:

    Hi Adam,

    I can't really test that without removing parts or cutting traces on the PCB. However, I don't think your second guess is this, as CONN_V1 (pin A1 of U2) is floating.

    The internal schematic is not in the datasheet. From your perspective, is the more plausible cause of this extra current is the delta in voltage between IN/EN and V+?

  • Mastermind 35665 points
    Adam Torma

    In reply to user4725373:

    Fred,

    Unfortunately we don't give out our internal IC schematics to protect our IP.

    I think its plausible that the extra current is the delta in voltage between IN/EN and V+ but 20mA seems high to me. I can probably find out by ordering some ICs and putting them on the bench to see how much current they consume with a delta between V+ and IN/EN voltages.

    Thank you,
    Adam
  • Mastermind 35665 points
    Adam Torma

    In reply to Adam Torma:

    Fred,

    I have confirmed the extra current consumption is due to phenomenon stated in the app note above. For these types of devices we recommend setting the control voltage to Vcc or GND.

    I set Vcc = 5.5 V and IN =3.3 V
    I measured Icc = 4.7mA.

    If I set IN = Vcc
    I measure Icc = <1uA

    Since you are only passing 3.3 V signals through the switch could you set the switch V+ pin to 3.3 V? This will eliminate the extra current consumption.

    thank you,
    Adam
  • Expert 1025 points
    user4725373

    In reply to Adam Torma:

    Thank you for taking the time to do that.

    These switches were powered at 5.6V because they were used to route a signal that could go up to 5.5V. I'll think of something else on the next revision.

    Have a great day,

    Fred

All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms of Use of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms of Use of this site. TI, its suppliers and providers of content reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.

TI Worldwide | Contact Us | my.TI Login | Site Map | Corporate Citizenship | mobile m.ti.com (Mobile Version)

TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs and
embedded processors, along with software, tools and the industry’s largest sales/support staff.

© Copyright 1995-2018 Texas Instruments Incorporated. All rights reserved.
Trademarks | Privacy Policy | Terms of Use