0-60 VDC POWER SUPPLY CONTROLLED BY PIC 0-5VDC

[chuzkin]

Hi friends.

I think i should give more detailed information.
What I need is to uso a PIC microcontroller, so using 2 push-buttons, I can increase / decrease the voltage level from 0VDC to 60VDC. The PIC output range is 0-5VDC, so I need an interface to convert this signal to 0-60VDC.
Current output needed 2.5 or 3A. Load is a magnet, with the following voltage/current measured:

40V - 2.08A
34.8V - 1.85A
30.3V - 1.26A
24.5V - 0.69A
18.4V - 0.12A
17V - 0.01A

The idea is to replace actual boards to get 50 or 60VDC in order to achieve a stronger magnetic force.


Thanks!

Best regards.

[valentinc]

      Hi,

      In order to produce an analog voltage output with a PIC microcontroller you need a digital to analog converter (or a microcontroller which has one integrated)... You also need an amplifier, a voltage reference and a power transistor...

       What is the input voltage of your system ?

[Psi]

If you're just controlling a magnet you can simply do PWM on the PIC from a 60VDC source.

eg..
75% duty cycle 60V pwm = power into magnet equivalent to a 45V DC source
50% duty cycle 60V pwm = power into magnet equivalent to a 30V DC source
25% duty cycle 60V pwm = power into magnet equivalent to a 15V DC source
(Note this is not strictly true but close enough, if you're over-driving the magnet past its rated voltage the efficiency goes down)

You just need
- a N-channel logic level mosfet
- 100R resistor between PIC output and mosfet GATE
- Generic diode that can handle 2A placed across the magnet for backEMF protection (arrow pointing towards the 60V)

Mosfet SOURCE to GND,  mosfet DRAIN to magnet, other magnet terminal to 60VDC

(Same circuit you will find everywhere for driving a relay from a 5V logic signal)