Driving high current load using a microcontroller port. 3

[Hoticenz]

Hi I am doing an research on driving high current load using a microcontroller port. I need some information on how I can make 20 mA that comes out of a microcontroller larger to make a load work and also how I can choose different interfaces for different types of load (mainly resistive, inductive and capacitive). Thank you.

 

[melone]

Based on the load / switching times / voltage & current levels, etc., you can use a FET or BJT transistor to drive your loads. You might even be able to get away with using a relay if the switching time is slow. A more detailed explaination of what you are trying to drive can help define the exact nature of the circuitry.

Keep us posted!

 

[Hoticenz]

Thanx for the info. I am doing a general research in this topic so I have to explain different solutions for different types of loads. I need to achieve more than 20 mA. I am mainly looking at resistive, capacitive and inductive loads. Thanks again for the info.

 

[MMAshwin]

Hi,

If I have to drive high loads from a microcontroller then I usually go for a darlingpair device.

Usually I use the ULN2003 which is 7 drivers on a chip capable of driving 500ma with only around 1ma draw at the input. The have clamping diodes built in and are workable up to 50V. The only problem is lack of electrical isolation, however there is no reason why you cann't couple these to the microcontroller with an opto isolator.
See the following ling for info

http://alds.stts.edu/datasheet/Interface/ULN2001.pdf

Talking of which you could always just use an opto isolator with a darlington pair or triac as the device being switched.
See the following link for info

http://www.isocomoptocouplers.com/isocom/icpl2730.htm

If you fancy a single device then try the BDX44 d-pair device, a bit more current & voltage.
See link for info

http://www-us7.semiconductors.philips.com/pip/BDX42_43_44_CNV_2

Regards

 

[Hoticenz]

I really appreciate all the help I am getting in this. Can you please help me in getting some information on what different types of interfaceses, devices, I can use to increase the current for different types of loads. Thank you.