DC/DC Converter (Miniature Remote Control Solar Car)

[williB]

Oh no.....I'm from Malaysia and it states that its one of the country where they wont send the samples to

I'll go buy them then. Thanks!

aaaaaw..sorry

 

[devonsc]

I read about this Half-Bridge Converter, it states that it is recommended to run loads between 500W to 1500W.

Can I still use this to convert from AC to a DC level and uses a buck converter to step-down the voltage for charging purposes?

 

[williB]

I read about this Half-Bridge Converter, it states that it is recommended to run loads between 500W to 1500W.

Can I still use this to convert from AC to a DC level and uses a buck converter to step-down the voltage for charging purposes?

got link?

 

[Nigel Goodwin]

true but thats what i started on , and that was complicated enough..

It's no more complicated than a 16F84, it's an upgraded direct replacement. There's only one change required to the code, and that's to disable the comparators - it takes two lines.

No point carrying on using obselete expensive parts!.

The 628's internal 4MHz oscillator even makes it far easier to use than an 84!, and it even has a hardware USART.

 

[devonsc]

**broken link removed**

Thanks

 

[Nigel Goodwin]

I read about this Half-Bridge Converter, it states that it is recommended to run loads between 500W to 1500W.

Can I still use this to convert from AC to a DC level and uses a buck converter to step-down the voltage for charging purposes?

You still haven't mentioned any values?, input and output voltages and output current would be helpful!.

As a matter of interest, I've never seen that half bridge converter circuit used in domestic electronics - even switchmode microwaves don't use it, and they are about 1000W or so. I am aware of the configuration though, as far as I'm aware it's to allow you to use lower voltage switching devices?.

 

[devonsc]

Sorry, I was thinking of:

Input - 240V AC and Output - 12-14V DC? (For charging purposes)

Is that the appropriate range needed for charging? sorry

 

[devonsc]

By the way, if the Half Bridge Converter can be implemented to obtain a DC voltage level of 12V for charging purposes, how do I determine the values of the capacitors?

Is there any calculations involve? Or I can just use high value, approximately 100microFarad?

Real sorry as I got to go to bed, have been staying all night long, its 6 in the morning here, having class later. Will be back to check replies? Thanks a lot...

Bye! Sorry to trouble you guys.

 

[williB]

how about a simple stepdown transformer..Got any lying around??
and a full wave rectifier.. filter caps .. Regulator...
Can u use a regulator.??

 

[devonsc]

Oh, I did that. I mean, are you talking about a linear regulator? I submitted that during our discussion with our lecturer last week but he wanted me to implement switching regulators instead of a linear regulator.

Correct me if I'm wrong, are you saying that, from the power supply, using a step-down transformer then rectifies it thorugh diodes and a capacitor in parallel with the load? Hope I'm not talking nonsense...

 

[williB]

Oh, I did that. I mean, are you talking about a linear regulator? I submitted that during our discussion with our lecturer last week but he wanted me to implement switching regulators instead of a linear regulator.

Correct me if I'm wrong, are you saying that, from the power supply, using a step-down transformer then rectifies it thorugh diodes and a capacitor in parallel with the load? Hope I'm not talking nonsense...

yes, but are u allowed to use a rgulator ..or do you have to build it with individual components..?

 

[devonsc]

oh yes yes, you mean regulators like LM317 IC and all? yes, im allowed to use them...any ideas on how can i build one with good efficiency? can i get them from you?

 

[devonsc]

williB? not that I dont want to "pay attention" while you're teaching me , but i guess i got to sleep. i will be back in...2 hours time to read ur replies.

thanks you so so so much

 

[williB]

oh yes yes, you mean regulators like LM317 IC and all? yes, im allowed to use them...any ideas on how can i build one with good efficiency? can i get them from you?

well i only have one LM317 targeted for my robot car. sorry

 

[samcheetah]

any ideas on how can i build one with good efficiency? can i get them from you?

the datasheet of the LM317 will give you alot of ideas for building a good regulated supply. and the LM317 is a commonly available regulator that you can find at any electronics shop

 

[devonsc]

Thanks for that guide regarding LM317.

Would to ask how does the transformer used in switch mode power supply varies from the one used in linear regulator? I thought the selection of proper transformer depends on the transformer ration? For instance, 240:12. Won't we need the same type of transformer for both linear regulator circuitry as well as switch mode regulator circuitry as the desired output is 12V DC?

Thanks...

 

[williB]

Thanks for that guide regarding LM317.

Would to ask how does the transformer used in switch mode power supply varies from the one used in linear regulator? I thought the selection of proper transformer depends on the transformer ration? For instance, 240:12. Won't we need the same type of transformer for both linear regulator circuitry as well as switch mode regulator circuitry as the desired output is 12V DC?

Thanks...

the transformer selection does depend on the ratio
as i understand it a switching powersupply somehow increases the frequency thus uses a physically smaller transformer.

 

[devonsc]

Hi there, I've read about the implementation of transformerless AC/DC converter. Not implementing this in the project, just want to ask something this form of AC/DC converter.

It states that it is not advisable to implement such transformerless AC/DC converter to certain applications, such as a battery charging circuit, where a user can easily have direct contact with the 240V AC supply, which is dangerous.

Would like to ask about the term "direct contact" used in here.

Just curious that certain house appliances that we're using has direct contact to the 240V AC supply as well. We do know that it is dangerous and we need to be aware of it and becareful while using them.

Does this mean that it is also practical to implement an transformerless AC/DC converter for a battery charging circuit, where the circuit is being "stored" in a proper casing?

Sorry for my nonsense again...

 

[devonsc]

the transformer selection does depend on the ratio
as i understand it a switching powersupply somehow increases the frequency thus uses a physically smaller transformer.

Does this mean that...I'm not sure the available transformers in the market, so for example:

Ratio of 240:24 at 60Hz is a bigger than 240:24 at 120Hz?

 

[Nigel Goodwin]

Ratio of 240:24 at 60Hz is a bigger than 240:24 at 120Hz?

The ratio is the same, but the transformer can be physically smaller - although 60Hz to 120Hz isn't enough of a change to make much difference.

A switch mode supply normally will work in KHz, sometimes in the 100KHz range, this reduces the transformer to about 10% of it's 50/60Hz size.