PWM Driver for Solenoids

[Exsaevio]

Hello my name is Marcus from Sweden so i apologize in advance if my spelling and explanation is of to begin with but i will try to explain my best. I am a noob with electronics but i have a project with a solenoid that i would like to fix. What i want is a Solenoid that vibrates with a freq of about 50 to 150 hz and i would like to control the length of the piston to vibrate with how long the pulse is. and i have done some research about PWM driver. My first plan was to take two 555 timer ic to make an PWM signal that i can change the duty and freq.But now i have research some more and because a solenoid is an inductance load that mite not be so good so i have looked at some dedicated driver like DRV103 that is a driver for solenoid. But the chip only have a freq adjust of 500hz- 100kh and a dutycycle of 10%-90%
And i would like more duty cycle and lower freq.
Sorry for dumb question i could be wrong with my calculation but i would like to get this to work. Is there an alternative chip? or can i adjust the DRV103 further?

hope you understand what i mean else i will try to explain more
Best regards

 

[tjnic]

I wouldn't have thought you need a special chip to drive this. You can deal with this the same way as you would a relay (search for switching relays with a transistor). You will need to put a diode across the solenoid to deal with the back EMF and switch it using an NPN transistor on the low (0V) side of the solenoid. The base of the transistor can be connected via a resistor to the output of the 555 PWM circuit. You will need to pick a resistor value that will keep the transistor saturated. There are plenty of calculators on the net that will help you work that out.http://www.kpsec.freeuk.com/trancirc.htm is a good place to start.