Need to amplify Digital output of 5V at 2.5 mA to get 5 V (or more) at 8 mA to turn on a SSR.
There are so many amplifiers that I’m struggling to narrow it down.
Hello,
Welcome to the Digikey tech forum. Looking at this it appears you’re trying to create power by amplifying 5v at 2.5ma to a greater value of more than 5v at 8ma which means you want more power than what’s available. Can you explain more on what you’re trying to achieve ?
A Measurement Computing USB-3101 digital out only does 2.5 mA at 4.8 V. I have to boost that 2.5 mA to turn on the SSR which needs 8 mA and 4 V. I bought a Mikroe boost 2 and a Adafruit Boost 1000 and neither boosts enough.
Thanks for any assistance you can give.
perhaps you can build a voltage regulator circuit using a part like LTC3620EDC#TRMPBF To get your voltage up for the relay.
Hi @cindydest ,
Thank you for your correspondence. One could build a simple transistor circuit to achieve this using the signal input provided along with a separate voltage supply. Otherwise an easier way would be to utilize either a pre-built level translator, signal conditioner, or some other type of interface.
Another option to consider would be 1597-1323-ND as this is powered and controlled by logic power (3.3V-5V) and would be able to turn on your SSR or much higher voltage/current output -a separate power supply of your choosing (min 5v@8mA) would be the only extra requirement. We do have many more options of these ranging from multi-channel to solid state as well. Depending on what your preferences, price range, and operating environment are, we may be able to narrow down better options.
I don’t want to create a circuit. I would like a pre-built circuit. I don’t have time to re-invent the wheel.
There are so many descriptions for ICs and circuits that it can be daunting to find a particular one.
I hadn’t thought of signal conditioners or level translators. That might work.
Hi cindydest,
Thanks to Ohm’s laws, you can’t boost the current without dropping the voltage on your I/O pin, as you can’t increase power without adding it from somewhere else.
Fortunately, based on info in the USB-3101 USB-based Analog Output User Guide, your device provides a 5V “Power Terminal” on pin 56. On page 20, it states that it can source up to 10mA, so, with a few external components, you can use your I/O pin and that 5V source to give a 5V, 10mA signal to drive that SSR relay input.
Something like this: (found here: Control Circuit for Solid State Relay | ATO.com)
R1 would only be necessary if the current isn’t internally limited in your SSR.
Another alternative would be to use another SSR with very low trigger current requirements to turn on your SSR. The LCA182 only needs 0.25 mA (250 uA) to turn on. You’d connect it something like this:
With R roughly about 3.9K Ohms, it will pull about 1 mA from your I/O pin. If your SSR does not have an internal current limiting resistor, then you would need to add that between the 5V and the input of the SSR.
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