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Topic: L293D power consume (Read 525 times) previous topic - next topic

xianwu

I used to use relay to control a DC motor, bi-direction. I think relay takes too much power. so I switch relay to L293D. it worked fine. but when motor is rotating,  L293D suck 20mA(5V) current. when I connect L293D pin 2, pin 7 to low. motor stopped, then L293D suck 25mA( 5V ). surprised, I'm expect current be less! anybody know why it take more current when motor not running.
note: current is for 5V, not 12V motor power.

second question, I don't want L293D take 25mA when motor is idle. How could I cut the 5V to L293D, and when I need run motor, just switch 5V on to L293D?  in my project power is critical.

Grumpy_Mike

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n my project power is critical.

Then the L293 is the wrong chip to use. There are other H-bridge chips, try and choose a CMOS one and not an old transistor one like the L293.

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anybody know why it take more current when motor not running.

It is just the way the internal buffer transistors are switched.

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How could I cut the 5V to L293D, and when I need run motor, just switch 5V on to L293D?

You should not do this. If an unpowerd IC has input signals applied to it then it can latch up, causing damage.

xianwu

thank you, Mike. I'll buy L9110S.

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