Diode - Basic Applications

Diode – Basic Applications

Yong Heui Cho @ Mokwon University

Some of slides are referred to:[1] A. S. Sedra & K. C. Smith, Microelectronic Circuits.

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Electronic Circuits

4. Diode – Operational Princi-ple5. Diode – V/I

6. Diode – Basic Applica-tions7. Diode – Advanced Applica-tions

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Half-wave Rectifier• Rectifier converts an AC into a DC by allowing a

current to flow through it in one direction only.

vO = 0, vS < VD0

RR + rD

vS - VD0R

R + rD

vO = vS ≥ VD0

≈ vS – VD0 , for rD ≪ R

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Full-wave Rectifier

PIV = 2VS – VD0

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Bridge Rectifier

vD3(reverse) = vO + vD2(forward)

PIV = Vs -2VD + VD = Vs - VD

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Voltage Regulator• VR automatically maintains a constant

voltage level– Zener diode or IC

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Ideal Peak Detector

Ideal case

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Real Peak Detectort1 < t < t2

Vr = VP – vO(T-ΔT) =

iDmax = IL(1 + 2π√2Vp/Vr)iDav = IL(1 + π√2Vp/Vr)

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DC Power Supply

V1 / V2 = N1 / N2

transformer

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Simple Power Supply• No transformer• Bridge rectifier, Zener diode, voltage di-

vider with C, peak detector

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IC-based Power Supply• Transformer, bridge rectifier, peak

detector, regulator IC