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Presentation 3: Detailed Design
and DFM considerations
Group 6 Lab 6
Presentation 3
Karl Silge
Power Supply
1
Power Supply block
+30V
collector
xfmr
+15V
xfmr
regulator
xfmr
regulator
op amps
-15V
+5V
digital
bridges
2
• Collector voltage: 300 mA @ 36V
• Digital supply
300 mA @ 8V
• Op amp supply
300 mA @ 35V
10.8W
2.4W
10.5W
• Total power input
23.7W
• Voltage tol. +/- 3.0 V for collector and op amp
supply voltage, +/- 0.5 V for digital supply
3
Key component selection
•
Transformers
– 120V/36V
– Dual output 120V/8V/35V
•
Rectifier
– Full wave bridge: 30V
– Full wave bridge: 8V
– Full wave bridge: 16V
•
Regulator
– Linear: +15V
– Linear: -15V
– Linear: +5V
•
Capacitor
– 1200 µF
– 1500 µF
4
Design calculation: capacitor
From Electronics, 2nd ed., Hambley, Allan, p. 143, to find a capacitor to smooth ripple in
a full-wave bridge rectifier,
where IL is the current drawn, T is the period of the voltage, and Vr is the allowable ripple
voltage. For this application , current is expected to be 300 mA max, 60 Hz line
current is used, and 2V ripple is allowable.
5
Capacitor sizing
The tolerance on capacitance for the capacitors is
±20%. Despite this seemingly large value, very little
effect will be seen. The purpose of the capacitor is to
reduce the ripple voltage seen by the regulator, to
determine the amount of this ripple
Capacitor
nominal
Ripple voltage
high
low
1200µF
1500µF
2.08
1.667
2.60
2.08
1.736
1.389
6
Regulator
• 3 V allowable ripple voltage
• As with any regulator, heat generation
must be considered. Regulators chosen
for this project are of the linear type, so
heat dissipation is calculated by
Q = (.300 A)(6.6 - 5)V = .48W
for the digital supply voltage, and
Q = (.300A)(15.8 – 15)V = .240W
for the two op amps.
7
Schematic
8
Power Block DFM Plan
Sub Circuit
Type
Example: 5VDC
Regulator
Example:
15VDC
Regulator
Example:
-15VDC
Regulator
Fn(s)
Applicable Worst Case Analysis Plan
(See DFM Analysis Guide)
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
R, L &
C Tol
R, L & C
Specs
Over
Current
Protect
V vs I
Regulation
Power
Semi
J Temp
Power
Semi
Package
Input
Voltage
Range
R: 5%
Rout:
1ohm
max
750 mA
1
125 C
TO-220
0-10
R, L &
C Tol
R, L & C
Specs
Over
Current
Protect
V vs I
Regulation
Power
Semi
J Temp
Power
Semi
Package
Input
Voltage
Range
R: 5%
Rout:
1ohm
max
750 mA
1
125 C
TO-220
0-10
R, L &
C Tol
R, L & C
Specs
Over
Current
Protect
V vs I
Regulation
Power
Semi
J Temp
Power
Semi
Package
Input
Voltage
Range
R: 5%
Rout:
1ohm
max
750 mA
1
125 C
TO-220
0-10
Task 8
Task 9
Task 10
9
Power Block DFM Plan
Sub Circuit
Type
Example:
Xfmr Diode
Bridge
Example:
Xfmr Diode
Bridge
Example:
Xfmr Diode
Bridge
Applicable Worst Case Analysis Plan
(See DFM Analysis Guide)
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Over
Current
Protect
Power
Semi J
Temp
Power
Semi
Package
Input
Voltage
Range
C Tol
C
Specs
Output
Voltage
Ripple
4A
125 C
D-70
DF02M
0 - 35
+/- 20%
Over
Current
Protect
Power
Semi J
Temp
Power
Semi
Package
Input
Voltage
Range
C Tol
4A
125 C
D-70
DF02M
0 - 35
+/- 20%
Over
Current
Protect
Power
Semi J
Temp
Power
Semi
Package
Input
Voltage
Range
C Tol
4A
125 C
D-70
DF02M
0 - 35
+/- 20%
Task 8
Task 9
Task 10
2V
C
Specs
Output
Voltage
Ripple
2V
C
Specs
Output
Voltage
Ripple
2V
10
Other Issues
• Safety: 1 A fuse
– Protection of equipment and user
– Transformers meet UL506 General Purpose
11
Packages
• Rectifier
–Full wave bridge: 30V D-70
DF02M
• Regulator
–Linear: +15V
–Linear: -15V
–Linear: +5V
TO-220
TO-226
TO-220
12
Power Supply Prototyping Plan
• Block Area
– 90 cm2
• Total PCB Area
– 90 cm2
• PCB Substrate Type
– Etched fiberglass
• Component Attachment Type
– Direct Solder
• Socketed Components
– Solid wire solder connection
• Types of Connectors
– AMP connections
13
Bill of Materials
•
item
•
•
Transformer (120V/8V) Digikey MT-2228-ND
bridge rectifier
Jameco 178204CC
Tamura 3FS-536
BR82D
1
1
•
Transformer
(120V/35V/8V)
bridge rectifier
regulator +5V
regulator +15V
regulator -15V
capacitor (1200 uF)
capacitor (1500 uF)
Digikey MT-1133-ND
Tamura PFT24-35
1
Jameco
Digikey
Digikey
Digikey
Digikey
Digikey
BR82D
TI UA7805CKTER
TI MC70L15ACLP
TI TL780-15CKC
Panasonic EEU-FM-A
Panasonic EEU-FM-A
3
1
1
1
1
2
•
•
•
•
•
•
supplier supplier p/n
178204CC
296-11108-1-ND
296-10228-5-ND
296-9607-5-ND
P12368-ND
P12406-ND
mfr.
mfr. p/n
qty/unit
14
PCB Layout
15
Work to be done
• Finalize regulator design
– Consider switching regulator
– Configuration change for linear design
capacitances
• Sizing of fuse
16