I know the design of DC to DC converters. They are either Buck converters or Boost converters. How they are related to switch mode power supply. Is that any other type ? or DC to DC converter are especial type of switch mode power supply ?

 

Buck and boost converters are both switching regulators. DC to DC converters are also switching regulators.

The other type of regulator is linear.

 

Thanks for the answer. I also have heard about flyback connectors. Are they also switch mode regulators ?

 

I also have a question on heat management. If a DC to DC converter has 10 Watt input power and 8 Watt output power. Then the loss is 2 Watt, right ? Where this 2 Watt is going ? Converterted to heat and lost ? Does it means to have a package that can handle 2 Watt loss or attachment of heat sink for 2 Watt loss ?

 

If a DC to DC converter has 10 Watt input power and 8 Watt output power. Then the loss is 2 Watt, right ?

We refer to that as having an efficiency of 80%.

Where this 2 Watt is going ? Converterted to heat and lost ?

You got it. It's lost as heat. 80% efficiency would be low for a switching regulator.

 

Where this 2 Watt is going ?

It's dissipated as heat, mostly in the switching transistor(s)' switching losses and on-resistance, and the inductor/transformer winding resistance.

 

This means that it's good practice to attach a heat sink with DC to DC converters as well, like we do in linear regulators.

 

This means that it's good practice to attach a heat sink with DC to DC converters as well, like we do in linear regulators.

Depending upon the dissipation, yes.

 

This means that it's good practice to attach a heat sink with DC to DC converters as well, like we do in linear regulators.

It depends. The benefit of switching regulators is that the pass transistor only dissipates power when it's on. Some of the disadvantages are that you have more ripple and they're more complex.

 

Thanks for the answer. I also have heard about flyback connectors. Are they also switch mode regulators ?

Yes, they are, but there is a transformer in both a flyback converter and a forward converter.
There are also a SEPIC (Single Ended Primary Inductor Converter) and a Ćuk converter.
The other fundamental type is the Buck-Boost.

 

The benefit of switching regulators is that the pass transistor only dissipates power when it's on.

It dissipates the most power while switching on and off. When fully on or off there is little dissipation. This is why gate drive circuitry is ver important.

 

It depends. The benefit of switching regulators is that the pass transistor only dissipates power when it's on.

The transistor(s) are on or off. Off=large V x 0A = 0 watts. On=very_small_V x full_current_A = small watts.
There is a very short time where the transistor is turning on or turning off. The power loss is large, but the time is very small. In this case(s) the power loss is large but time is close to zero, so the power loss is small.
There are "resonant" power supplies where one or both edges have near zero power loss.

There are many types of power supplies.

 

The4 most of SMPS means galvanic isolation between primary and secondary in piercy contrast to step-up or step-down regulators. Thus all having 1) halfbridge with capacitive midpoint 2) full H-bridge and 3) the skewed bridge 4) push-pull - are sure the smps. Contrary, the circuits like step-up, step-down, inverted, buck-boost, multiplicated (Wilson, Cockroft-Walton, switched capacitor), Čuk, Sepic, Zeta, DAB etc are not.

 

Actually there are several different kinds of switching power supplies although mostly they either raise or lower thr output relative to the input voltage. I suggest visiting the TI website and reading on their switch applications section. There is a lot of good information.