ECEN325: Electronics Spring 2014 · 2020. 10. 30. · • Full-Wave Rectifier +Reduces capacitor...
Transcript of ECEN325: Electronics Spring 2014 · 2020. 10. 30. · • Full-Wave Rectifier +Reduces capacitor...
Sam PalermoAnalog & Mixed-Signal Center
Texas A&M University
ECEN325: ElectronicsSpring 2014
Diode Rectifier Circuits
Rectifier Circuits
[Karsilayan]
2
Half-Wave Rectifier
[Karsilayan]
3
Half-Wave Rectifier Transfer Characteristic
[Karsilayan]
[Sedra/Smith]
• Only rectifies positive half of the input signal• Lose one diode voltage drop from the peak value
4
Half-Wave Rectifier w/ a Filter Cap
[Karsilayan]
( )( )
( ) RCt
poRCt
p
s
o eVtVttttt
eV
VtVtV
1
11
21
0,,7.0 −
− =
⇒<<<<−
=
5
Half-Wave Rectifier w/ a Filter Cap[Karsilayan]
6
Half-Wave Rectifier w/ a Filter Cap[Karsilayan]
7
Half-Wave Rectifier w/ a Filter Cap[Karsilayan]
RV
I pR ≈
8
Half-Wave Rectifier w/ a Filter Cap[Karsilayan]
(assuming a triangular capacitive current profile)
9
Full-Wave Rectifier
VVPIV s 7.0ˆ2 −=
[Sedra/Smith]
• Positive ½ cycle• Top diode on
• Negative ½ cycle• Bottom diode on
[Karsilayan]
10
Full-Wave Rectifier Transfer Characteristic
[Karsilayan]
[Sedra/Smith]
• Rectifies all of the input signal• Lose one diode voltage drop from the peak value
11
Bridge Rectifier
[Karsilayan]
VVPIV s 7.0ˆ −=
[Sedra/Smith]
• Positive ½ cycle• D1 & D3 on
• Negative ½ cycle• D2 & D4 on
-0.7V
Vs-0.7V-0.7V
Vs-0.7V
12
Bridge Rectifier Transfer Characteristic
• Rectifies all of the input signal• Lose two diode voltage drops from the peak value
[Karsilayan]
13
Full-Wave & Bridge Rectifier w/ a Filter Cap
[Sedra/Smith]
• The capacitor only discharges for T/2• Results in ½ Cap size for a given ripple• Roughly ½ diode current
LLpr CR
TVV2
=
+=
r
pRDavg V
VII
21 π
+=
r
pRD V
VII
221max π
14
Rectifier Trade-Offs
• Half-Wave Rectifier+Simplest design with fewest components- Requires largest capacitor for a given ripple
• Full-Wave Rectifier+Reduces capacitor size by ½ relative to half-wave- Requires center-tapped transformer- PIV almost double that of half-wave
• Bridge Rectifier+Reduces capacitor size by ½ relative to half-wave+Save PIV as half-wave rectifier- Lose two diode voltage drops in peak value
15