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Designing a 6V DC to 12V DC converter

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ahsan

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Hello

I want to design a 6Vdc to 12Vdc convertor, what type of circuitry is needed to achieve this? i have heard that DC to DC convertors (or DC transformers)are used for this purpose. Is there any such convertor available in IC package??
 

dc to dc converter cockcroft walton

U can use the charger pump or simple switch cap double voltage
 
simple 6vdc to 12vdc circuit

Depending on power you would like to convert, for low current (<200mA) you can use charg-pump configuration, for higher currents there is Boost/Step-up method.
Another method is Flyback / Isolated / Transformer...

More you can read here:
**broken link removed**
and here:
**broken link removed**
you can use "Design" option.
 

Re: DC to DC converter

use voltage doubler. Refer to this classical paper:

'A High-Efficiency CMOS Voltage Doubler'
Pierre Favrat, Philippe Deval, and Michel J. Declercq,
JSSC, VOL. 33, NO. 3, MARCH 1998
 

Re: DC to DC converter

Dear ahsan,

You only specify DC voltage-voltage conversion from 6Vdc to 12Vdc, but what about the current rating?

For low power application, typically 100mA, i.e. only for the sole purpose of signal conversion, you can use:

1. A Switched-Capacitor Circuit (sometimes known as Cockcroft-Walton or Charge Pump), however this only achieves half-cycle conversion.

2. A Back-to-back Switched Circuit for full-cycle conversion.
**broken link removed**

N.B. You can use an op-amp or a MOS transistor to switch the capacitors. I would recommend a MOS transistor. In above cases, the output voltage suffers from two diode (forward voltage) drops.

3. A 555-timer as a voltage doubler.
**broken link removed**

All the above assume that you only have a 6Vdc to work with. If however you have 12Vdc and you only want to convert an input signal of 6Vdc to switch full-swing of 12Vdc, simply use a MOS transistor with Vds of slightly more than 12Vdc and Vth of any value below 6Vdc. Most MOS transistors used in this manner are usually Power MOS with Ids current rating of 1A at least, thus can deliver sufficient power to your load.

For high power application, you can use a transformer to step up (boost) your input voltage. Stepping up serves one purpose, but the electrical isolation of a transformer is what offers your circuit the necessary protection.
 

DC to DC converter

LM3478 (National semiconductor) OR ADP3000 (Analig Devices) will do the job. Basically they are Boost Regulators.
 
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Re: DC to DC converter

you can you boost dc dc use inductor and large cap
the right process is high voltage process
 

Re: DC to DC converter

Here is a good paper on the design on some
DC-DC converters, refer this it might be useful.
 

Re: DC to DC converter

I want to make a DC_DC converter too. I've readn datasheet of TL494 (Motorola) .there're a DC_DC converter ,I want do it but don't know calculate the transform . Can you help me.
 

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Re: DC to DC converter

is there any ckt for conversion 1-5v to 0-5v

reply soon its urgent
 

Re: DC to DC converter

I wanna have a 24vdc to 12vdc step down converter.
I get this circuit worked & regulated the output to around 12.7V.
The problems is how can I get 5A at the 12.7V output?

I tried to load 1A but the input ampere also loaded 1A, doesn't mean the input current are lower than the output load? The mosfet & the 10R resistor get very hot in a minute. Also, the inductor getting noisy with a 68R load.

here are my schematic, pls help.

 
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Re: DC to DC converter

Something is wrong in this schematic. How TL494 drives the power transistors? You must be missing a wire form C1 output to Q1 gate.
 

Re: DC to DC converter

Something is wrong in this schematic. How TL494 drives the power transistors? You must be missing a wire form C1 output to Q1 gate.

Hello mdorian,

Thanks for yr input.
Yes, I missed out a connection from C1 & C2 to the collector of Q3 in the schematic.

This is originally a 24VDC to 12VDC converter that I have. But output 3A only. How can I increase the output to 5A?

If I load a 12V 21W bulb, the current at the 24V side is 1.6A, 12V side is 1.7A.
The 10R resistor getting very hot.

The original converter, which 24V side is around 0.7A & 12V side is 1.7A, using TL594, BC846A & BC850B while I'm using BC546B from On Semi.


Any idea why my circuit doesn't work?
 
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Re: DC to DC converter

Are you sure that R19..R22 have 10 ohm? At 3 Amps current the power on R9..R22 is I^2 * R = 9 * 2.5 = 22,5W , to much. Please check again the value. For the same reason you don't have a lower current on input as expected.
 

Re: DC to DC converter

Are you sure that R19..R22 have 10 ohm? At 3 Amps current the power on R9..R22 is I^2 * R = 9 * 2.5 = 22,5W , to much. Please check again the value. For the same reason you don't have a lower current on input as expected.

Hello mdorian,

The marking is R10 SMD resistor.
Also the IC is TL594 but I'm using TL494.
 

Re: DC to DC converter

"R10" means 0.1 ohm for smd resistors you should check all values on the schematic. I didn't worked with TL494 or 594 so read carefully the datasheets they look to me identical except for the undervoltage lockout control which is not important in your case.
 

Re: DC to DC converter

"R10" means 0.1 ohm for smd resistors you should check all values on the schematic. I didn't worked with TL494 or 594 so read carefully the datasheets they look to me identical except for the undervoltage lockout control which is not important in your case.

Hello mdorian,

Thanks for pointing me the R10 is 0.1R. I replace with 4 x 0.1R now it works very well.
24V side around 0.8A, 12V side around 1.6A with a 12V 21W bulb @12.7V.

How can I increase the output current to 5A? The circuit output around max.2A as if I tried to load the output at 2.8A the output voltage drops to around 8V only.

Am thinking of increase the size of inductor will this help? Any idea?
 

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