SMPS Halogen Lamp Circuit

SMPS Halogen Lamp Circuit mostly need transformer for working.

This post talk about new type transformer using switching power supply.

It is more simple than older transformers and can work with other bulbs too if they do no use radio wave RF.

This new design also save energy.

What is a SMPS Halogen Lamp Circuit:

A power supply circuit made for safely power halogen lamps is called SMPS (Switched Mode Power Supply).

Halogen lamps need steady and controlled power and they run at high heat.

So SMPS is used to give fixed voltage or current to turn on halogen lamp properly.

Circuit Design and Working:

Parts List:

MOSFETs in half bridge style are used in circuit and it runs by IR2153 chip and this chip have RC oscillator and floating driver for top MOSFET.

Transformer from mains give around 107V when working at about 50 kHz frequency.

Formulas and Calculations:

Voltage formula is like this:

Uef = (Uvst − 2) × 0.5 × √(t − 2 × deadtime / t)

where:

• Uef is a final voltage coming out which is the effective voltage.
• Uvst is goal voltage SMPS try to reach or keep.
• t is time in switching maybe from timing part.
• Deadtime is short pause time in SMPS switch cycle.
• The part (t − 2 × deadtime / t) shows how voltage change with timing.
• The 0.5 number is scaling to fix voltage output.

Transformer Tr1:

This transformer use ferrite core EE or EI type and it come from old computer power supply like AT or ATX.

The core size should be around 90 to 140 mm².

How many wire turns needed depends on bulb it needs.

To stop magnetic loss and winding is done like this:

20 turns bottom + 20 turns top is the secondary

40 turns in primary for normal ATX.

Transformation Ratio:

If input is 230V and we want 107V at transformer primary then:

Ratio = 107V / 11.5V = 9.304

If bulb is 12V but works good at 11.5V and secondary have 4 turns then:

Primary = 9.304 × 4t = 37t

Be sure winding is correct for best working.

Safety Warning:

Be very careful because almost all parts of this circuit are connected to mains voltage which is high voltage

If transformer Tr1 is not made good then dangerous mains voltage can go to the output.

So always follow safety rules while making or using this halogen transformer.

To keep it safe and for working good all steps must be done very carefully.

Below is the guide to make the transformer:

Circuit Design:

Make circuit diagram using instructions from start.

Put IR2153 IC, pulse transformer Tr1 and half-bridge with MOSFETs.

Check if circuit board gets enough space to fit all parts and connect them good.

Transformer Construction:

If ferrite core is not in right shape then cut and shape it same like transformer design.

When winding primary coil do like 20 turns under and 20 turns above the secondary and follow the way it say.

First remove all secondary and top part of old primary winding.

Now wind new secondary coil use correct number of turns for the bulb voltage we want.

Before putting core back together be sure all windings are sealed properly.

Circuit Assembling:

Solder all parts on circuit board same like the layout and design.

Make half-bridge connection from IR2153 IC to MOSFETs.

Connect capacitor divider and diode bridge same like in circuit diagram.

Before giving power check transformer is connected with correct polarity.

Use multimeter to test voltage at many points in circuit if something is not working.

If output is not good then try changing number of turns on transformer or other settings.

Troubleshooting:

If problem happen then use oscilloscope and multimeter to check and fix the issue.

Conclusion:

Always be careful while building or using SMPS Halogen Lamp Circuit because halogen bulbs can get very hot.

It is important to follow all safety rules and laws.

Better to follow design rules and safety steps to stay safe.

References:

Halogen Lamps Technical Specifications data