Your SlideShare is downloading. ×
Power supply - more than a battery with a knob
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Power supply - more than a battery with a knob

800
views

Published on

This presentation “Today's Power Supply; More Than a Battery With a Knob" shows how the features and capabilities of a modern power supply can solve many power problems. …

This presentation “Today's Power Supply; More Than a Battery With a Knob" shows how the features and capabilities of a modern power supply can solve many power problems.

Agilent Technologies offers a broad selection of both bench-friendly and system-ready DC power supplies from 2W to 6600W.

Published in: Design, Business, Technology

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
800
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
40
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Todays Power Supplies; More Than a Battery With a KnobToday’s Power Supplies: More Than Page 1a Battery With a Knob
  • 2. Agenda: • Categories of Power Supplies • How People Use Power Supplies • Selecting the Right Power Supply • Output Characteristics (Ripple, Noise, Speed, Accuracy) • Control via Computer and/or Analog Inputs • Output Measurement/Monitoring Capabilities • Packaging (Size, Number of Outputs, Front/Rear Terminals) • Special Capabilities (DUT protection, Output Disconnect/Reversal) • Unique Features and Capabilities • Sequencing of Multiple Outputs • Power Arbitrary Waveforms with List Mode • Noise and Shielding / Hints and Tips • Tricks of the TradeToday’s Power Supplies: More Than a Page 2Battery With a Knob
  • 3. Power Supply Categories• Basic Supplies • Manual or Programmable • Used for setting bias, powering circuits, etc.• Performance Supplies • Faster, more accurate, higher power • Typically used in system applications• Modular Supplies • Compact, flexible, mix-and-match • Easily interconnected• Specialty Supplies • Battery Simulation • Solar Array Simulation• Open Frame SuppliesToday’s Power Supplies: More Than a Page 3Battery With a Knob
  • 4. What do People do with Power Supplies? Task Meaning Power Supply Required Basic DC Bias •Set the output to one voltage or current Basic Power Supply (PS) to power the Device Under Test (DUT) Burn-in •Lots of power or lots of channels Basic PS Margin Testing Depends on •Test DUT at a variety of points in DUT operating range Basic PS required speed •Speed can be important or or on required if high throughput is required or Performance PS accuracy if DUT is being tested at a lot of different points of V setting Turn-on and •Multiple outputs must be sequenced Performance PS Inrush Testing •Measure how much current is drawn when DC bias is first applied Characterization •Stimulate the DUT with a time varying voltage Performance PS using Waveforms to test under dynamic test conditions •Speed matters Parametric •Characterize performance of transistors, Precision Source Measure Unit Testing of Devices diodes, resistors and capacitors Device/Parameter Analyzer Today’s Power Supplies: More Than aPage 4Battery With a Knob Page 4
  • 5. Power Supply Output Characteristics • Ripple and Noise • Ideal output is free from any voltage variations; In practice, never the case • Ripple = periodic variations, usually line related • Noise = random variations • Typically specified as either Vrms or Vp-p • Vp-p shows the maximum variation away from the DC set point • Programming Accuracy • Measure of how closely the output will be to the setpoint • Specified as a percent of output plus an offset • Can determine if the power supply has the precision required • Many power supplies have built-in voltmeters and ammeters to measure output • Output Response • When the set point or the load changes, it takes time for the output to change • Slew rate is a result of the power supplies regulation and output bandwidth • Typically specified for a voltage change from 10% to 90% of its rated output • Also specified for a load change of 50% to 100%Today’s Power Supplies: More Than a Page 5Battery With a Knob
  • 6. DC Power Supply TopologiesLinear or series-pass • Applications • Bench & laboratory • Automated test • Low power: < 500 W• Advantages • Low output ripple & noise • Fast programming speed Note: Agilents linear Power • Fast transient recovery Supplies classically have fast• Disadvantages programming speed which • Low efficiency make them a good fit in test • High weight/watt systems. • Physically largeToday’s Power Supplies: More Than a Page 6Battery With a Knob
  • 7. DC Power Supply TopologiesSwitched mode (SMPS) • Applications • Subassembly test • Burn-in • Bench & laboratory • Electromechanical test• Advantages • High power in small package **Note: Agilents newest • High efficiency Switching Power Supplies• Disadvantages have noise, slew rate, • Moderate to high** ripple & noise programming speed and • Moderate programming speed transient performance nearly • Moderate transient recovery that of linear suppliesToday’s Power Supplies: More Than a Page 7Battery With a Knob
  • 8. Key Power Supply Specs: Comparing Noise Hint High Noise Noise is very dependent on Typical PC Power Supply output voltage, (not an instrument) so a 5V output will have much 100 mVpp less noise than a 100 V output Typical Switching Agilent (SMPS) Supply Switching 20 mVpp Supply Typical 10 mVpp Agilent Low Noise Linear Supply Switching Supply 1 mVpp Agilent Linear Supply Low NoiseToday’s Power Supplies: More Than a Page 8 Page 8Battery With a Knob
  • 9. Controlling the Power Supply• Computer Interfaces • Many DC power supplies have both manual and computer control • Hardware interfaces can include GPIB, USB, and LAN• Analog Voltage Control Signal • Some power supplies provide an analog voltage control input • The power supply acts as an amplifier, providing current up to its rated maximum • Use the Analog Control input to: • Amplify the power of the input signal • Track an analog voltage Today’s Power Supplies: More Than a Page 9 Battery With a Knob
  • 10. Output Measurements • Many power supplies have a built-in voltmeter and ammeter to read back its own output • The measurements can be displayed on the front panel or queried by a computer connected to the interface • These measurements are particularly useful in computer controlled systems • Measurement (or read back) accuracy is specified as a percent of full scale plus an offsetToday’s Power Supplies: More Than a Page 10Battery With a Knob
  • 11. Remote Sense (150 mV drop)Lead resistance cancontribute a significantvoltage drop between the I =10 Ampsoutput of the supply and theactual voltage presented atthe load (150 mV drop) 5.3 VThe sense leads measure thevoltage present at the loaditself, and adjusts the output High Z I =Zeroof the supply to compensate Inputfor the voltage drops in theleadsToday’s Power Supplies: More Than a Page 11Battery With a Knob
  • 12. Remote Sensing Best Practice: Minimize Wiring Path Impedance • Four steps to minimize path impedance: • Use larger gauge, twisted pair wire. • Reduce distance between power supply and DUT. • Minimize the use of relays / connectors. • Select relays / connectors to minimize contact resistance; consider initial and end of life specs. • Beware of transient response issues for dynamic loads • Use an adequate bypass capacitor at the DUT • Consider a supply tailored for remote sensing with pulsed loadsToday’s Power Supplies: More Than a Page 12Battery With a Knob
  • 13. Physical Characteristics• Physical size / Form Factor • Half rack width or full rack width, some vendors offer ¼ rack width • Height ranges from 1U to 4U (1.75 in to 7.00 in). • Half rack width is generally better for bench applications • Full rack width works well in system racks• Front or Rear Output Terminals • System and high current power supplies have their outputs located on the rear panel • Bench and some low current power supplies have their outputs on the front• Number of Outputs • Multiple output power supplies can save space on the bench or in a rack Today’s Power Supplies: More Than a Page 13 Battery With a Knob
  • 14. DC Power Supply Capabilities• Constant voltage (CV) mode VSet CV • Output sensing I• Constant current (CC) mode V CC ISetToday’s Power Supplies: More Than a Page 14Battery With a Knob
  • 15. Output Characteristics• Rectangular • Dual-range Pmax Vmax Pmax Vmax Pmax Imax Imax Vmax• Autoranging Maximum power range ImaxToday’s Power Supplies: More Than a Page 15Battery With a Knob
  • 16. Special Capabilities • Protecting the Device Under Test • Over Voltage Protection (OVP) • Over Current Protection (OVP) • Discrete Fault Indicator (DFI) / Remote Inhibit (RI) • Protecting the Power Supply • Over Temperature Protection (OTP) • Output Disconnect Relay • Output Polarity ReversalToday’s Power Supplies: More Than a Page 16Battery With a Knob
  • 17. Output protection features Inhibit (INH) / FAULT (FLT) Daisy-Chain of Three Power Supplies for Emergency Shutdown Power Supply A Power Supply B Power Supply C +S +S +S + + + Load Load Load - - - A -S B -S C -S 1 1 1 FLT FLT FLT 2 2 2 3 3 3 INH INH INH 4 4 4 • For multiple bias input subassemblies, if one bias supply senses a failure, all should be shut down • TTL Input/Output • Fault definition defined by system controller at set-upToday’s Power Supplies: More Than a Page 17Battery With a Knob
  • 18. Unique Feature: Down Programming • Capacitors discharge slowly under light loads -Static voltage source: no problem -Varying voltage levels: slow tests • Down programming -Rapidly decrease the output voltage -Reducing discharge times by hundreds of msToday’s Power Supplies: More Than a Page 18Battery With a Knob
  • 19. Unique Feature: Sequencing• Precise synchronization of bias voltage turn on and off• Improper turn-on or -off may cause damage to DUT• Modular power supplies often have built-in sequencing capabilities• Example applications • LCD testing • PC motherboardToday’s Power Supplies: More Than a Page 19Battery With a Knob
  • 20. Output Sequencing Using the Agilent N6700-series OUTPUT ON V1 V2 Module 1 V3 Module 2 Delay 2 Module 3 V4 Delay 3 Module 4 Delay 4 • Can control output sequencing between modules with 1 ms resolution • Can control slew rate from 1 ms to 10 seconds for 0 to max V transition • Useful for powering up devices, PC boards, or subassemblies that require control of multiple bias supplies during startup • Can also set the output off sequence independently • Extendable across mainframes for > 4 outputs Today’s Power Supplies: More Than a Page 20 Battery With a Knob
  • 21. Unique Feature: Arbitrary Waveforms/List Mode• Advanced feature available in N6700 and 66000 only*• LIST mode allows power supply to output a waveform like an Arbitrary Waveform Generator (ARB) • Slower than an ARB, but MUCH more power than an ARB• For each point, you program a V, I, and step time• LIST mode can change the output faster than a PC can send commands• Example: LIST mode rapidly steps through test conditions for fast throughput V t * Also available in specialized products: AC Source, DC LoadsToday’s Power Supplies: More Than a Page 21 Page 21Battery With a Knob
  • 22. Example of High Speed Margin TestAutomotive Engine Control UnitToday’s Power Supplies: More Than a Page 22 Page 22Battery With a Knob
  • 23. TIP #1: Eliminating Sources of Noise • Start with a low noise power supply • it’s easier to eliminate noise at the source than to filter it out later • Use good connection practice to avoid pickup: • eliminate loops; twist and shield connections from power supply to DUT • carefully route power lines from ac mains to supply • think through grounding connections; prefer a single point groundToday’s Power Supplies: More Than a Page 23Battery With a Knob
  • 24. TIP #2: More Power• Connect Power Supplies in series for higher voltages• Connect Power Supplies in parallel for higher currentsToday’s Power Supplies: More Than a Page 24Battery With a Knob
  • 25. TIP #3: Use the right productivity tools• Some power supplies are specialized per specific application• Some power supplies contain special features to make your job easier• Examples • Battery drain software • Solar array simulator I-V curves • Built-in V vs. time, I vs. time views • Data loggingToday’s Power Supplies: More Than a Page 25Battery With a Knob
  • 26. The N6705B DC Power AnalyzerBoosts the productivity of the R&D EngineerIntegrates multiple instrument functions into a single box • 1 to 4 advanced power supplies • Digital voltmeter and ammeter • Arbitrary waveform generator • Oscilloscope • Datalogger • All functions and measurements are available from the front panel Gain insights into your DUTs power consumption — in minutes, not hours — without writing a single line of code! Today’s Power Supplies: More Than a Page 26 Battery With a Knob
  • 27. Summary • Categories of Power Supplies • How People Use Power Supplies • Selecting the Right Power Supply • Output Characteristics (Ripple, Noise, Speed, Accuracy) • Control via Computer and/or Analog Inputs • Output Measurement/Monitoring Capabilities • Packaging (Size, Number of Outputs, Front/Rear Terminals) • Special Capabilities (DUT protection, Output Disconnect/Reversal) • Unique Features • Tricks of the TradeToday’s Power Supplies: More Than a Page 27Battery With a Knob

×