Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

  • State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 30 subscribers
  • Views 2243 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.

Can multiple LM1875 be connected in parallel and share same power supply

Susan Nicholas
Other Parts Discussed in Thread: LM1875

I would like to build an 8-channel amplifier to control 8 mini-solenoids. I would like to use 8 x LM1875 (1 for each channel). Can 8 x LM1875 be connected in parallel and share the same power supply, or would they interfere with one another?

  • 0
    TI__Expert 3840 points

    Hi Susan,

    I want to fully understand your your needs.

    It sounds like you want 8 amplifiers to be powered off of the same power supply but yet each amplifier will drive an independent solenoid, independently; ie from a separate source?  Is this what you mean?

    You can parallel 8 LM1875s, but the topology that I am thinking of connects all of the inputs together (ie driven by the same source) as well as the outputs to allow for higher output current to drive a lower impedance load. This topology can be found in SNAA021A, Figure 6 page 13 for example. Is this the type of topology you are thinking of? http://www.ti.com/lit/an/snaa021a/snaa021a.pdf

    To answer your question regarding interference; they would only interfere with one another to the level of PSRR over frequency. Typically this isn't too much of a problem if the power supply has a low enough impedance at the frequency of concern. If the amplifiers are connected as discussed above in SNAA021A, then as they are driven by the same source, interference wouldn't be an issue as they are all operating simultaneously.

    Best Regards,

    JD

  • 0 in reply to John De Celles

    Hi JD,

    I would like to have an 8-channel soundcard on a PC driving 8 mini-solenoids, so each channel would drive an independent solenoid via a LM1875, with +-9V dual power supply. Two (or more) solenoids need to operate simultaneously (typically at 100Hz for 50ms) but exactly which two solenoids, out of the eight, will vary from trial to trial under software control. It is for a psychology tactile experiment.

    The maximum voltage to one solenoid is +- 6V and the maximum output current to one soleoid is 300mA. Can the 8 x LM1875 share the same power supply?

     Regards,

    Sue

     

  • 0 in reply to Susan Nicholas
    TI__Expert 3840 points

    Hi Susan,

    Yes, all 8 LM1875s can share the same power supply. Your power supply just needs to be able to handle the maximum number of loads that you intend to drive simultaneously.

    Best Regards,

    JD