Hello,
I am trying to design a circuit to drive a 12VDC motor from a 20V battery and I would like to ask for your help.
The application is the following: I want to power a 12V dc motor using a 20 V battery. I used a DC DC converter to convert the 20V from the battery to 12V. The issue I had is the motor has a 30A inrush and 2A steady current, and when I turned on the motor the high inrush current activated the overload protection on my converter.
I decided to use an NTC thermistor to limit the inrush current and then a 555 timer to bypass the thermistor after 1 second. I have a led connected to the 555 output to see when it is ON. The issue I have is when I turn on the switch, the motor starts running through the thermistor, and the 555 turns on and off the output for a few seconds, and then leaves it ON until the switch is turned off. I think in those first few seconds the voltage drops because of the high inrush current (as both 555 and motor are powered from the same 12V). Is there something I can do to avoid this to happen? I don't want to use any programable ICs, I want to do this as simply as possible, but I don't want the 555 output to turn on and off when starting
Also, I tried to do the same with a PTC thermistor (10ohm) instead of a NTC thermistor, but the effect is even worse, the 555 output turns on momentarily and then is off again, so the PTC thermistor is not bypassed for too long, and the cycle repeats every 1 second
Thank you for your help!
I am trying to design a circuit to drive a 12VDC motor from a 20V battery and I would like to ask for your help.
The application is the following: I want to power a 12V dc motor using a 20 V battery. I used a DC DC converter to convert the 20V from the battery to 12V. The issue I had is the motor has a 30A inrush and 2A steady current, and when I turned on the motor the high inrush current activated the overload protection on my converter.
I decided to use an NTC thermistor to limit the inrush current and then a 555 timer to bypass the thermistor after 1 second. I have a led connected to the 555 output to see when it is ON. The issue I have is when I turn on the switch, the motor starts running through the thermistor, and the 555 turns on and off the output for a few seconds, and then leaves it ON until the switch is turned off. I think in those first few seconds the voltage drops because of the high inrush current (as both 555 and motor are powered from the same 12V). Is there something I can do to avoid this to happen? I don't want to use any programable ICs, I want to do this as simply as possible, but I don't want the 555 output to turn on and off when starting
Also, I tried to do the same with a PTC thermistor (10ohm) instead of a NTC thermistor, but the effect is even worse, the 555 output turns on momentarily and then is off again, so the PTC thermistor is not bypassed for too long, and the cycle repeats every 1 second
Thank you for your help!
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