Overview Of A DC/DC Boost Converter
A boost converter is required mostly in a battery powered application. For example, driving a 24 V solenoid from a 12 V battery source. These converters are widely available from many online store especially from Ali Express. They cost around 3 US Dollars.
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| A ready-to-use 12 V to 31 V boost converter based on MC34063A I made. |
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| Soldering side I vanished it with a clear acrylic paint to protect from corrosion. |
MC34063A is very low cost DC/DC converter IC. It accepts the input voltage range from 3 V to 40 V. The maximum output current rating is up to 1.5 A peak. Since it bases on a switching power supply, the switching frequency is up to 100 kHz.
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| A sample of MC34063A I bought from E Bay. |
This device could creates three basic switching power supply typologies:
- A buck converter
- A boost converter
- A polarity inverter
In this first post on MC34063A, I create a DC/DC boost converter that step up a 12 V DC voltage to 31 V amplitude of the DC voltage.
This chip is very sensitive. It could be burned whenever a wrong connection, or an over voltage is applied. I burn a lot of them during my circuit prototyping.
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| Pin diagram and internal simplified schematic of MC34063A |
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| Pin Configuration And Function |
The vendor make a sample design of a boost converter with connection diagram and a sample calculation for the design.
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| A design sample of a boost converter made by the device manufacturer. |
The manufacturer stated the requirement this design as below.
The calculation for components value, voltage, current rating and frequency was done in the following details from the datasheet.
The resistor R1 and R2 are the voltage divider circuit to make a reference voltage that regulate the output voltage.
CT is a capacitor input for oscillator. It is around thousand pico Farad.
The value of inductor determines the maximum output current.
1N5819 is a high speed switching diode with the current rating up to 1A. If it doesn't exist we could use any ultra fast recovery diode - UF400X series.
DC/DC Boost Converter Design In Proteus
Using the application note from the vendor as list above, I create my own custom PCB design for this step up converter for my personal usage. I recalculate for the resistor R1 and R2 to make a 31 V output voltage due to my requirement.
I follow the design requirement, But due to the lack of components value to accurately fit the design. The output voltage a little error.
Fixed Boost Version
The design file for fixed boost version as shown in the pictures at the top could be downloaded here.
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| Schematic Diagram For Fixed Boost Converter |
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| PCB Copper Pattern |
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| Top Components Silk |
Variable Boost Version
In this version boost voltage output is varied according to the adjustment of the POT RV1.
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| A variable boost version |
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| Schematic Diagram |
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| A simulation sample, the output voltage is about 31 V. |
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| Copper Side |
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| Top Silk |
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| A finished PCB design |
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| A sample of 3D of the design |
The design file of the variable boost version could be downloaded here.
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