use of DC to DC converter..

[EngrRaymondC]

As the name implies, the DC-DC converter "converts" a DC signal to a different DC level(Higher/Lower). In AC, stepping up/down voltage is easy using a transformer. In DC, it's a bit more complex because you can't use transformers anymore. The stepping up/down in DC is done using the following:
a.) Linear Voltage Regulators(78xx) -not so efficient
b.) Buck Converter -Efficient up to ~95%
c.) Boost Converter - Efficient ~95%

When you think about it, you can decrease the voltage of a circuit using Potential Dividers but that won't be very efficient. For example, to convert 4V to 3 volts, you will need to put in series a 30 ohm and 10 ohm resistor (or get a value of similar ratio) and get the required 3 volts across the 30ohm resistor. As you can see, it's not efficient because 1 volt is "lost" due to the 10 ohm resistor(efficiency is 75%). That is why a DC/DC converter is used.

Hope this helps you.

 

[tpetar]

In DC, it's a bit more complex because you can't use transformers anymore.

Sorry can you tell me how Power Inverters works from 12V DC to 220V like on example ? What they use instead transformers ?

What SMPS PSU uses inside ?


Here is not needed voltage boosting, he need to regulate voltage from 9V to 5V or 3,3V.


:wink:

 

[EngrRaymondC]

Hello,

Yes, you are right, the voltage across the terminals of a power supply is higher that the voltage at the end of the transmission line because of the power loss of the copper wire. In DC systems, the power loss in long TL is very large because of the copper loss/heat loss or the I2R loss because of the long wires. As you can remember, the resistance of a wire is:R=pL/A where: p (rho) is the resistivity of the conductor(ohm/m), L is the length of conductor(m) and A is the cross sectional area (m2). Therefore, the longer the wire, the higher the resistance.

Hope this helps.

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Hello Tpetar,

Thanks for your interest.
Correct me if I'm wrong but I think in power inverters(DC to AC), we use an oscillator to convert DC to a low level AC voltage and the output of the oscillator will then be fed to an output transformer. The transformer steps up the AC voltage output of the oscillator(i.e. 220V).
Thanks.

 

[jeffrey samuel]

@engrRaymondC

that is cool my man but the fact and the qn here is to convert a 9V dc to a 3 odd V of supply the point is based on the efficiency the mechanism can be used.

other factors like higher current must be strictly followed as higher current are not the favourite foe some of the devices

 

[tpetar]

Thanks for your interest.
Correct me if I'm wrong but I think in power inverters(DC to AC), we use an oscillator to convert DC to a low level AC voltage and the output of the oscillator will then be fed to an output transformer. The transformer steps up the AC voltage output of the oscillator(i.e. 220V).
Thanks.

Yes my friend, that is standard way, there is others method but this is let say conventional way. :wink: