1. ELG 4135 :Electronics III Fall Voltage Filters Analysis, design and implementation of active filters in DC power supplies Presented to : Dr.R.Habash Presented by: Alaa Farhat Mohammed Al-Hashmi Mubarak Al-Subaie November ,

2. Outline Brief Overview of Filters DC Power Supply System
Filter Types and Classification
Passive Low Pass Filter Circuits
Drawbacks
Proposed Solution
Simulation Results
Improvements
Future Work
References

3. A Brief Overview of Filters In General
An electrical filter is a device designed to separate, pass or suppress a group of signals from a mixture of signals.
Electrical filters may be classified in a number of ways
-Technology
-Transfer function
-Topology

4. Basic DC- Power Supply

5. Original, half-wave rectified, and full-wave rectified signals
Original, half-wave rectified, and full-wave rectified signals. (Top to bottom)

6. Basic DC- Power Supply

7. Filter Types

8. Passive Low Pass Filter Frequency Response
Actual Response
Ideal Response

9. Used DC Voltage Filter Circuits
Simple Capacitor Filter
RC Capacitor-Input Filter
- Negative gain
LC Capacitor-Input Filter
-Not favored in electronics

10. Problems Magnitude attenuation Maximum gain <1
Requires a DC-DC converter
Pass band must be greater than cutoff frequency
Fixed cutoff frequency

11. The need for an alternative
New technologies using existing power lines to transmit data over different frequencies
-PLC (Power Line Communication)
-PLT (Power Line Telecommunication)
-PLN (Power Line Networking)

12. Solution Active filter type - Eliminate attenuation
- Allow a positive gain
Band Pass filter
- Allow frequency selection
Higher order filter
- Higher quality factor

13. Band Pass Filter Design
C = C1 = C2
k = 2 π fo C
R2 = Q/(A.k)
R3 = Q/(2Q^2 – A).k
R1 = 2Q/k

14. Band Pass Filter Designed Circuit

15. Simulation Results

16. Simulation Results

17. Improvements Unity gain Highly selective frequency tuned
to 60 Hz by design
Tuning:
Gain can be adjusted by adjusting R2
F0 can be shifted by adjusting R1

18. Future Work
Implement a circuit with multiple outputs (High, low, and band pass)
Use as a common filter for other applications next to serving role in power supply

19. References
[1] Phelps, T. K., and W. S. Tate. Passive Input Filter Design, Proceedings of the Sixth National Solid-State Power Conversion Conference, (PowerCon 6), Miami Beach, FL, May 1979.
[2] Sedra, S, and Smith, C, Microelectronic Circuits, Fifth Edition, Oxford, New York , pp