Power Sources & Management

1. Power Sources & Management ECE 450

2. Batteries http://www.electrictoolguide.com/types-of-batteries

3. Batteries http://www.electrictoolguide.com/types-of-batteries

4. Capacity Discharge vs Voltage (Alkaline) http://www.societyofrobots.com/batteries.shtml

5. Temperature EffectsLithium Ion Batteries http://www.societyofrobots.com/batteries.shtml

6. Storage CharacteristicsLithium Ion Batteries http://www.societyofrobots.com/batteries.shtml

7. Discharge RatesLithium Ion Batteries http://www.societyofrobots.com/batteries.shtml

8. Alkaline Batteries Not Fit for High Drain Electronic Devices

9. VCC Battery Connections Parallel Connection* Series Connection VCC 28mA 1.5v 1.5v 1.5v 1.5v 28mA GND 28mA 28mA GND

10. Voltage Regulators

11. MC7800, MC7800A, LM340, LM340A Series, NCV7805APPLICATIONS INFORMATION Design Considerations The MC7800 Series of fixed voltage regulators are designed with Thermal Overload Protection that shuts down the circuit when subjected to an excessive power overload condition, Internal Short Circuit Protection that limits the maximum current the circuit will pass, and Output Transistor Safe–Area Compensation that reduces the output short circuit current as the voltage across the pass transistor is increased. In many low current applications, compensation capacitors are not required. However, it is recommended that the regulator input be bypassed with a capacitor if the regulator is connected to the power supply filter with long wire lengths, or if the output load capacitance is large. An input bypass capacitor should be selected to provide good high–frequency characteristics to insure stable operation under all load conditions. A 0.33 F or larger tantalum, mylar, or other capacitor having low internal impedance at high frequencies should be chosen. The bypass capacitor should be mounted with the shortest possible leads directly across the regulators input terminals. Normally good construction techniques should be used to minimize ground loops and lead resistance drops since the regulator has no external sense lead.

12. IC: Index Mark Typical Bases TO-220 TO-92 8-DIP 8-SMD

13. 7805 Unregulated input Regulated Output Ground Schematic for a simple 7805-based power supply From 9V battery Or battery pack +7 VDC to +20 VDC To Robot Circuits +5 VDC C1 1F C2 0.1F +

14. 7805 Unregulated input Regulated Output Ground Schematic for a simple 7805-based power supply From 9V battery Or battery pack +7 VDC to +20 VDC To Robot Circuits +5 VDC C3 100F C1 1F C2 0.1F +

15. Circuit Noise Bypassing is the reduction of high frequency current flow in a high impedance path by shunting that path with a bypass, usually a capacitor. Bypassing is used to reduce the noise current on power supply lines. Decoupling is the isolation of two circuits on a common line. The decoupling network is usually a low pass filter and the isolation is rarely equal in both directions. Decoupling is used to prevent transmission of noise from one circuit to another. In practice, bypassing is always used when decoupling. Most circuits require bypassing, not decoupling. Using decoupling techniques to accomplish bypassing will give disappointing, if not disastrous, results. Complete understanding of both concepts is vital.

16. 7805 Unregulated input Regulated Output Ground Schematic for a 7805-based power supply From 9V battery Or battery pack +7 VDC to +20 VDC To Robot Circuits +5 VDC C3 100F C1 1F C2 0.1F C1Bulk 220F C1Bulk 220F + + +

17. Types of Capacitors

18. Capacitor Ratings

19. Capacitor Ratings

20. Diodes Zener Diode Diode Schottky Diode

21. 7805 Unregulated input Regulated Output Ground Schematic for a 7805-based power supplyReverse Current Flow Protection D1 1N5817 (Schottky) To Robot Circuits +5 VDC From 9V battery Or battery pack +7 VDC to +20 VDC C1 1F C2 0.1F +

22. 7805 Unregulated input Regulated Output Ground Schematic for a 7805-based power supplyOverload of Regulated Voltage D1 1N5817 (Schottky) To Robot Circuits +5 VDC From 9V battery Or battery pack +7 VDC to +20 VDC C1 1F ZD1 5.6V Zener 1N5232B C2 0.1F +

23. Improvements to Simple 7805 Voltage Regulator • Include the capacitors suggested by the manufacturer. After that, add a bulk capacitor to the regulated output and to the unregulated power supply • Use a low-resistance, p-channel power MOSFET to prevent damage from a reverse battery • Add various low- and medium-value capacitors of different chemistries and technologies at various places on the circuit board to collectively benefit form their individual strengths. • Include at least one 0.1 F capacitor for every chip to bypass board impedance (providing a “local” power supply) and to decouple (isolate and reduce) circuit noise. Put each capacitor as close as possible to its targeted chip, and keep the lead length of each capacitor as short as possible. • Add a PPTC overcurrent-protection device to limit the maximum current that can flow through the robot. • Add a 5.6 V zener diode to the 5V regulated circuit to prevent damage from overload.

24. 7805 Unregulated input Regulated Output Ground Improved Schematic for a 7805-based power supply D1 1N5817 (Schottky) To Robot Circuits +5 VDC battery pack + + + + C4 1000F C1Bulk 220F C4 0.1F C1 1F C2 0.1F C2Bulk 220F ZD1 5.6V Zener 1N5232B

25. Butterworth Filters