Buck converter (SMPS)

[Hero999]

It depends on where you live; where I live the IEE regulations govern what is acceptable and what isn't and it's a little bit more complected than that.

Anything below 60VDC or 25VAC in dry conditions doesn't need to be insulated from the user at all.

Voltages between 60VDC or 25VAC and 120VDC or 50VAC, only need a single layer of insulation from the metal chassis or the user and there is no need for the chasses to have an earth connection (class 3).

Voltages above 120VDC or 50VAC, either need double insulation from the metal chassis or the user (class 2) or single insulation from the chassis and an earth connection to the chassis (class 1).

Solar pannels would be class 3 if they ran at 94VDC, they'd need to be insulated from the user but you wouldn't need to worry about earthing or double insulation.

 

[doupoumist]

Hi,
I want to make a dc dc buck converter with a 9V dc input and output has to be 4V dc. I am getting nowhere!!!! can somebody please show me an example of a circuit to follow

 

[ronsimpson]

Hi,
I want to make a dc dc buck converter with a 9V dc input and output has to be 4V dc. I am getting nowhere!!!! can somebody please show me an example of a circuit to follow

Your project is very different than what we have been talking about. Please start a new thread.

 

[WTP Pepper]

Most modern micros have in built PWM as part of their timer controllers. SiLabs C8051F320 springs to mind. It can run very fast.

 

[ronsimpson]

Most modern micros have in built PWM as part of their timer controllers. SiLabs C8051F320 springs to mind. It can run very fast.

Most micro controller PWM are a timer. They only make a duty cycle. They don't easy drive a power transistor or MOSFET.

Most PWM ICs have a error amplifier, reference, oscillator, current limit function, power driver, soft start function, power up delay, some have thermal shutdown, and a PWM function.