8/7/2019 Quasi Resonant Converter - Batch 10

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7.5W QUASI RESONANT

CONVERTER

ZERO CURRENT SWITCHING

BUCK CONVERTER

BHARADWAJ S

RAHUL G N

PREMCHAND

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SPECIFICATIONSInput : 10V to 15V

Output : 9V, 1.5A, 7.5W

Buck Converter

Controller 555 Timer

Frequency 100 to 67KHz

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BLOCK DIAGRAM

POWER CIRCUIT

CONTROL

(Switch)

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BASIC OPERATIONAL CIRCUIT

Quasi Resonant Converter PWM Converter

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OPERATION

When Switch is closed

When Switch isopen

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CONTROL CIRCUIT

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POWER CIRCUIT

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CIRCUIT DIAGRAM

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ON and OFF times in 555 Timer.Ton = 0.693(R1 + R2)C1

Toff = 0.693(R2)C1

For Zero Current Switching

Io = Vin (Cr/Lr)

Resonant Frequency = 1/(2 LrCr)

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EAGLE SCHEMATIC

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PCB LAYOUT

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ADVANTAGES Small in size.

Less sensitive to temperature.

Highly efficient.

Controllable outputs.

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APPLICATIONSSwitching Mode Power Supplies

LED Lighting Systems