help improving my circuit

[samsamm777]

Hey! I'm pretty newbie to electrical engineering, and this is very much my hobby. So please be gentle. I've been working on a circuit to control a 5v PC case fan. To be used as a soldering smoke extractor. It runs of a single cell lipo battery, and can be charged via usb. I think im happy with my design with regards to the usb, charging and power regulation. However im really struggling with an approach to the fan speed control. Im using a 555 to drive a mosfet for the motor load, which im sure will work. However.. it just doesnt seem like the right solution. Im sure theres a pwm ic i can use which do the job for me, but im struggling to find something. Any advice would be much appreciated.

[Benta]

Your schematic is pretty much unreadable, sorry.

A couple of general comments:
1: 5 V PC fans are almost all brushless DC motor powered with integrated controllers.
2: 2-wire 5 V PC fans should be controlled by a relatively low frequency PWM, eg, 100 Hz. You're turning on and off the controller all the time.
3: using a modern 4-wire PC fan is much easier. You just need to provide a 25 kHz PWM signal on a separate pin.

Price wise I see no major difference today.

[samsamm777]

Your schematic is pretty much unreadable, sorry.

Would you mind possibly elaborating on why its unreadable? I've tried to separate all the logical blocks to keep things tidy.

[Benta]

Your schematic is pretty much unreadable, sorry.

Would you mind possibly elaborating on why its unreadable? I've tried to separate all the logical blocks to keep things tidy.

My apologies. Somehow the "zoom" function didn't work in my browser. A restart fixed that.