Author Topic: Repurpose an h-bridge as "double switch"  (Read 933 times)

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Offline MoriambarTopic starter

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Repurpose an h-bridge as "double switch"
« on: March 19, 2019, 09:32:13 pm »
Hi,
I have, in my "bin" some h-bridge circuits that are left from a previous project. These are not single ics, but made up with mosfets, and used to drive a 12V brush dc motor.

Currently I have a project where I have to switch some leds on and off, meaning that when one is on the other is off and viceversa. These are either blue or white LEDs but the rest of the circuit is 3.3V logic (but I have a 12V power supply). In order to get rid of these extra parts put to use those already assembled h-bridges, I thought of the circuit in the schematic below, thinking that putting a resistor in series with both LEDs would "take" the most voltage drop, thus protecting the reverse biased led (there's always one when the bridge is active) from dying.

Is this a sensible idea? If not, is it at least an ok reasoning (albeit not best)? If not again, where am I wrong?

Thanks
 

Offline viperidae

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Re: Repurpose an h-bridge as "double switch"
« Reply #1 on: March 20, 2019, 01:03:27 am »
You don't need to worry about reverse voltage if you wire one led to each output and their other terminal to positive or negative via a resistor.
 
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Offline Brumby

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Re: Repurpose an h-bridge as "double switch"
« Reply #2 on: March 20, 2019, 01:54:36 am »
I don't see anything basically wrong with your idea - but I would consider using H-bridge switching as over-kill.
 
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Offline MoriambarTopic starter

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Re: Repurpose an h-bridge as "double switch"
« Reply #3 on: March 20, 2019, 07:09:55 am »
I don't see anything basically wrong with your idea - but I would consider using H-bridge switching as over-kill.
Thanks, indeed it is.
 


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