1. Presentation 3: Detailed Design and DFM considerations
Group 6 Lab 6
Presentation 3
Karl Silge
Power Supply

2. Power Supply block collector xfmr op amps xfmr regulator xfmr
+30V
collector
xfmr
+15V
op amps
xfmr
regulator
-15V
xfmr
regulator
+5V
digital
bridges

3. Collector voltage: 300 mA @ 36V 10.8W
Digital supply V 2.4W
Op amp supply V 10.5W
Total power input W
Voltage tol. +/- 3.0 V for collector and op amp supply voltage, +/- 0.5 V for digital supply

4. 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

5. 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.

6. 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
Ripple voltage
Capacitor nominal high low
1200µF
1500µF

7. 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)( )V = .48W
for the digital supply voltage, and
Q = (.300A)(15.8 – 15)V = .240W
for the two op amps.

8. Schematic

9. Applicable Worst Case Analysis Plan (See DFM Analysis Guide)
Power Block DFM Plan
Sub Circuit
Type
Applicable Worst Case Analysis Plan
(See DFM Analysis Guide)
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Task 8
Task 9
Task 10
Example: 5VDC
Regulator
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
Example: 15VDC
Example:
-15VDC
Fn(s)

10. Applicable Worst Case Analysis Plan (See DFM Analysis Guide)
Power Block DFM Plan
Sub Circuit
Type
Applicable Worst Case Analysis Plan
(See DFM Analysis Guide)
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Task 8
Task 9
Task 10
Example: Xfmr Diode Bridge
Over Current Protect
Power Semi J Temp
Power Semi Pack-age
Input Voltage Range
C Tol
C Specs
Output Voltage Ripple 4A
125 C
D-70
DF02M
0 - 35
+/- 20% 2V

11. Other Issues Safety: 1 A fuse Protection of equipment and user
Transformers meet UL506 General Purpose

12. Packages Rectifier Regulator Full wave bridge: 30V D-70 DF02M
Linear: +15V TO-220
Linear: -15V TO-226
Linear: +5V TO-220

13. Power Supply Prototyping Plan
Block Area
90 cm2
Total PCB Area
PCB Substrate Type
Etched fiberglass
Component Attachment Type
Direct Solder
Socketed Components
Solid wire solder connection
Types of Connectors
AMP connections

14. Bill of Materials item supplier supplier p/n mfr. mfr. p/n qty/unit
Transformer (120V/8V) Digikey MT-2228-ND Tamura 3FS
bridge rectifier Jameco CC BR82D
Transformer Digikey MT-1133-ND Tamura PFT
(120V/35V/8V)
bridge rectifier Jameco CC BR82D
regulator +5V Digikey ND TI UA7805CKTER 1
regulator +15V Digikey ND TI MC70L15ACLP 1
regulator -15V Digikey ND TI TL780-15CKC
capacitor (1200 uF) Digikey P12368-ND Panasonic EEU-FM-A 1
capacitor (1500 uF) Digikey P12406-ND Panasonic EEU-FM-A 2

15. PCB Layout

16. Work to be done Finalize regulator design Sizing of fuse
Consider switching regulator
Configuration change for linear design capacitances
Sizing of fuse