I have an array of 8 motors (operating current between 200 and 500 mA @9V) and a controller with max. output of 20mA @5V. Most of the time (99.5%) all motors are idle, and are getting powered on in sequence (no two motors will ever work simultaneously).

I'm new to electronics and haven't familiarized myself with many kinds of devices yet. As to my knowledge, my problem can be solved with an 8-channel multiplexer + 8 transistors. I want to avoid using relays if possible. My project is supposed to be battery-powered, so minimal power consumption in standby mode is very desirable. I guess there should exist a class of devices / ICs that combines a multiplexer with an array of transistors in a single package, but without knowing what I'm looking for exactly I only came across digital/analog multiplexers (which are not fit for handling currents of more than ~100mA as far as I know) and multi-channel switch arrays like TPD2005F - but these require 8 output pins from my MCU and I want to save them for other purposes.


simulate this circuit – Schematic created using CircuitLab

Is there a type of IC that resembles given description? If no, what could a typical solution architecture look like?

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    \$\begingroup\$ The downvote is likely because this is a product recommendation. \$\endgroup\$
    – DKNguyen
    Aug 6, 2022 at 16:49
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    \$\begingroup\$ @user2417480 - Hi, If you edit your question & title to make it clear that you are looking for types of IC, or a solution architecture, rather than specific device recommendations, then any objections regarding this as a shopping-type question would be rendered "moot" and the question can be reopened. (Adding a block diagram / schematic would help too.) || Note to other site members: There is nothing stopping you recommending specific devices (e.g. as examples of types of devices) in an answer. You don't have to do it, but you can. The rule is against shopping-type questions. Thanks \$\endgroup\$
    – SamGibson
    Aug 6, 2022 at 18:12
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    \$\begingroup\$ you might want to look into actual motor drivers, since you will probably find one that does what you want (and may have other features that would be helpful too) \$\endgroup\$
    – BeB00
    Aug 6, 2022 at 20:13
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    \$\begingroup\$ Can you cheat and use low side drive switch (transistor)? If yes, a demux as Jens suggests, 8 bog standard MOSFETs + 8 dito diodes would do the job. \$\endgroup\$
    – winny
    Aug 6, 2022 at 20:19
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    \$\begingroup\$ No, to turn on each motor. Your present schematic has motor- tied to ground and +9 V is switched. If that’s not a requirement, tie motor+ to +9 V and switch the ground for each motor with a MOSFET. \$\endgroup\$
    – winny
    Aug 7, 2022 at 10:21

1 Answer 1


You can use a demultiplexer IC like 74HC238 or CD4028 to decode a 3 bit address to 8 discrete outputs. This can be used in combination with e.g. the mentioned TPD2005F to control the motors. Such a solution is not very common.

There are 8 bit power shift register with open drain outputs, controlled with 3 wire SPI signals, e.g. BD8LB600FS, L9825, BD16938AEFV or MC33298.

Have a look at the quiescent current consumption, low side darlington driver arrays like ULN2803 in combination with a CMOS demultiplexer can win here.


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