Welcome to the training module on [PWM Controllers for Power Supplies]
This training module will Introduce you to PWM controller and its’ different Topologies.
The switching regulator is increasing in popularity because it offers the advantages of higher power conversion efficiency and increased design flexibility multiple output voltages of different polarities can be generated from a single input voltage.
The most commonly used switching converter is the Buck, which is used to down-convert a DC voltage to a lower DC voltage of the same polarity. This is essential in systems that use distributed power rails (like 24V to 48V), which must be locally converted to 15V, 12V or 5V with very little power loss. The Buck converter uses a transistor as a switch that alternately connects and disconnects the input voltage to an inductor. When the switch turns on, the input voltage is connected to the inductor. The difference between the input and output voltages is then forced across the inductor, causing current through the inductor to increase.
The Boost regulator takes a DC input voltage and produces a DC output voltage that is higher in value than the input (but of the same polarity). Whenever the switch is on, the input voltage is forced across the inductor which causes the current through it to increase (ramp up). When the switch is off, the decreasing inductor current forces the &quot;switch&quot; end of the inductor to swing positive. This forward biases the diode, allowing the capacitor to charge up to a voltage that is higher than the input voltage. During steady-state operation, the inductor current flows into both the output capacitor and the load during the switch off time. When the switch is on, the load current is supplied only by the capacitor.
The Buck-Boost or Inverting regulator takes a DC input voltage and produces a DC output voltage that is opposite in polarity to the input. The negative output voltage can be either larger or smaller in magnitude than the input voltage. When the switch is on, the input voltage is forced across the inductor, causing an increasing current flow through it. During the on time, the discharge of the output capacitor is the only source of load current. When the switch turns off, the decreasing current flow in the inductor causes the voltage at the diode end to swing negative. This action turns on the diode, allowing the current in the inductor to supply both the output capacitor and the load.
The Flyback is the most versatile of all the topologies, allowing the designer to create one or more output voltages, some of which may be opposite in polarity. Flyback converters have gained popularity in battery-powered systems, where a single voltage must be converted into the required system voltages for example, +5V, +12V and -12V, with very high power conversion efficiency. The most important feature of the Flyback regulator is the transformer phasing, as shown by the dots on the primary and secondary windings. When the switch is on, the input voltage is forced across the transformer primary which causes an increasing flow of current through it.
The Push-Pull converter uses two to transistors perform DC-DC conversion, The converter operates by turning on each transistor on alternate cycles (the two transistors are never on at the same time). Transformer secondary current flows at the same time as primary current. An important characteristic of a Push-Pull converter is that the switch transistors have to be able the stand off more than twice the input voltage
All of the switching converters use a form of output voltage regulation known as Pulse Width Modulation (PWM). Put simply, the feedback loop adjusts (corrects) the output voltage by changing the ON time of the switching element in the converter.
The UCC38083/4/5/6 is a family of BiCMOS pulse width modulation (PWM) controllers for dc-to-dc or off-line fixed-frequency current-mode switching power supplies. The dual output stages are configured for the push-pull topology. Both outputs switch at half the oscillator frequency using a toggle flip-flop. The dead time between the two outputs is typically 110 ns, limiting each output’s duty cycle to less than 50%.
The application circuit shows an isolated 12-VIN to 2.5 VOUT push-pull converter with scalable output power (20 W to 200 W). Note that the pinout shown is for SOIC-8 and PDIP-8 packages
OUTA and OUTB are shown at a duty cycle of 80%, with the associated voltage VRS across the current sense resistor of the primary push-pull power MOSFETs. The current flowing out of CS generates the ramp voltage across the filter resistor RF that is positioned between the power current sense resistor and the CS pin. This voltage is effectively added to VRS to provide slope compensation at VCS, pin 3. A capacitor CF is also recommended to filter the waveform at CS.
This page gives PWM Controller Line card from different suppliers with different topologies from Premier Farnell.
This page gives PWM Controller Selection Guide from different suppliers with different topologies from Premier Farnell.
This page gives Evaluation Kits details from different suppliers from Premier Farnell.
This page gives Application Notes details from different suppliers from Premier farnell.
This page gives Reference Design details from different suppliers from Premier Farnell.
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1. PWM Controller for Power Supplies
2. Introduction <ul><li>Purpose </li></ul><ul><ul><li>An Brief Study on PWM Controller for Power Supplies from Texas Instruments </li></ul></ul><ul><li>Outline </li></ul><ul><ul><li>Switching Converter Topologies </li></ul></ul><ul><ul><li>Buck, Boost, Flyback, Push-Pull converter </li></ul></ul><ul><ul><li>Pulse Width Modulation Technique </li></ul></ul><ul><ul><li>Current Mode Push Pull PWM controller: UCC38083/4 </li></ul></ul><ul><ul><li>Reference Design solution from UCC38083/4 </li></ul></ul><ul><ul><li>solution from Premier Farnell for PWM Controller </li></ul></ul><ul><li>Content </li></ul><ul><ul><li>18 pages </li></ul></ul>
3. Switching Converter Topologies <ul><li>Buck: used to reduce a DC voltage to a lower DC voltage. </li></ul><ul><li>Boost: provides an output voltage that is higher than the input. </li></ul><ul><li>Buck-Boost (invert): an output voltage is generated opposite in polarity to the input. </li></ul><ul><li>Flyback: an output voltage (as well as multiple outputs) lesser or greater than the input can be generated. </li></ul><ul><li>Push-Pull: A two-transistor converter that is especially efficient at low input voltages. </li></ul><ul><li>Half-Bridge: A two-transistor converter used in many off-line applications. </li></ul><ul><li>Full-Bridge: A four-transistor converter (usually used in off-line designs) that can generate the highest output power of all. </li></ul>
4. Buck Regulator Switching Buck Regulator Inductor Current
5. Boost Regulator Switching
6. Buck-Boost (Inverting) Regulator
7. Flyback Regulator Switching
8. Push-Pull Converter
9. Pulse Width Modulation (PWM) <ul><li>The series of square wave pulses is filtered and provides a DC output voltage that is equal to the peak pulse amplitude multiplied times the duty cycle </li></ul><ul><li>output voltage can be directly controlled by changing the ON time of the switch </li></ul>
10. Current Mode Push-Pull PWM Controller <ul><li>Programmable Slope Compensation </li></ul><ul><li>Internal Soft-Start on the UCC38083/4 </li></ul><ul><li>Cycle-by-Cycle Current Limiting </li></ul><ul><li>Low Start-Up Current of 120 μA and 1.5 mA Typical Run Current </li></ul><ul><li>Single External Component Oscillator </li></ul><ul><li>Programmable from 50 kHz to 1 MHz </li></ul><ul><li>High-Current Totem-Pole Dual Output Stage Drives Push-Pull Configuration with 1-A Sink and 0.5-A Source Capability </li></ul><ul><li>Current Sense Discharge Transistor to </li></ul><ul><li>Improve Dynamic Response </li></ul><ul><li>Internally Trimmed Bandgap Reference </li></ul><ul><li>Undervoltage Lockout with Hysteresis </li></ul>
13. PWM Controller Line card Y Y Y Y Y click click TI Y Y Y Y Y click click ST Y click click Power Integrations Y Y Y Y Y click click OnSemi Y Y click click National Y Y Y Y Y Y click click Fairchild Pull- Push Full- Bridge Half- Bridge For ward Flyback with MOSFET Fly back Newark Farnell Supplies Topology
15. Evaluation Kits NCP1215 click NCP1215 5 W ADAPTER EVB Onsemi NCP1271 Click NCP1271 57 W Adapter Evaluation Board Onsemi NCP1013 Click NCP1013 6/12 W Adapter Evaluation Board Onsemi NCP1207 Click NCP1207AADAPGEVB Onsemi NCP1203 Click NCP1203GEVB Onsemi LM5073 Click Application Note 1574 LM5073 Evaluation Board National LM5026 Click Application Note 1387 LM5026 Evaluation Board National LM5020 Click Application Note 1314 LM5020 Evaluation Board National FSFR2100 Click FEB212 Evaluation Board Featuring FSFR2100, Fairchild Power Switch for Half-Bridge Resonant Converters Fairchild Part Number URL Evaluation Kits Title Manufacturer
16. Application Notes UCC2895 http://www.ti.com/litv/pdf/slua501 Apr/09 UCC2895 Layout and Grounding Recommendations TI UCC25600 http://www.ti.com/litv/pdf/sluu341b Dec/08 A 300-W, Universal Input, Isolated PFC Power Supply for LCD TV Applications TI UCC38C42 http://www.ti.com/litv/pdf/slua257 Feb/02 UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers TI TOP259 http://www.powerint.com/sites/default/files/PDFFiles/di182.pdf Jul/08 65 W Notebook Adapter PI TOP261 http://www.powerint.com/sites/default/files/PDFFiles/di196.pdf Jun/09 Ultra-low Profile 65 W Notebook Adapter PI TOP246Y http://www.powerint.com/sites/default/files/PDFFiles/epr13.pdf May/01 43 W / 57 W (peak), 5 Output Power Supply PI TNY376 http://www.powerint.com/sites/default/files/PDFFiles/di115.pdf Nov/07 7.5 W (13 W peak) Multiple Output STB Power Supply PI TOP257 http://www.powerint.com/sites/default/files/PDFFiles/di162.pdf Nov/07 30 W Set-top Box Power Supply PI NCP101x http://www.onsemi.com/pub/Collateral/AND8134-D.PDF Oct/03 Designing Converters with the NCP101X Family Onsemi NCP1200 http://www.onsemi.com/pub/Collateral/AND8042-D.PDF Feb/01 Implementing Constant Current Constant Voltage AC Adapter by NCP1200 and NCP4300A Onsemi NCP120x http://www.onsemi.com/pub/Collateral/AND8076-D.PDF Apr/03 A 70 W Low Standby Power Supply w/NCP120x Series Onsemi NCP1200 http://www.onsemi.com/pub/Collateral/AND8069-D.PDF May/03 Tips and Tricks to Build Efficient Circuits with NCP1200 Onsemi NCP1219 http://www.onsemi.com/pub/Collateral/AND8393-D.PDF Jul/09 48 W, 24 V/7.5 V Universal Input AC-DC Printer Adapter Using the NCP1219 Onsemi FAN6791 http://www.fairchildsemi.com/an/AN/AN-6083.pdf Mar/09 AN-6083: FAN6791- Highly Integrated, Dual-PWM Combination Controller Farichild FAN6753 http://www.fairchildsemi.com/an/AN/AN-6753.pdf Jul/09 AN-6753: FAN6753 ? Highly Integrated Green-Mode PWM Controller Farichild FAN7602 http://www.fairchildsemi.com/an/AN/AN-6014.pdf Jul/09 AN-6014: AN-6014 Green Current Mode PWM Controller FAN7602 Farichild FAN7601 http://www.fairchildsemi.com/an/AN/AN-4129.pdf Jul/09 AN-4129: Green Current Mode PWM Controller FAN7601 Farichild Part Number URL Date Published AN Title Manuf -acturer
17. Reference Design UCC3809 click Mar/09 19 Watt AC Input LED Driver Reference Design TI Click Aug/06 DAK-54 LinkSwitch PI LNK564 Click Jul/06 RDK-83 LinkSwitch-LP PI LNK613 Click Jan/09 RDK-160 LinkSwitch-II PI LNK626 Click Jan/09 RDK-201 LinkSwitch-CV PI Click Feb/07 RDK-203 PeakSwitch PI NCP1014 Click Feb/08 5 W CCCV AC-DC Adapter GreenPoint® Reference Design Onsemi NCP1562 Click Feb/08 200 W Game Console AC-DC Adapter GreenPoint® Reference Design Onsemi FSFR2100 Click Jul/07 200W Power Supply For LED Lighting featuring FSFR2100 and FAN6961. View App Note. Farichild SG6859 Click Nov/07 10W High Performance Fly-back Converter Module. Featuring SG6859. View App Note. Farichild SG5851 Click Nov/07 Reference Design Featuring SG5851, the Green Mode PWM Controller. Featuring SG5851. Farichild FSQ0765 Click Sep/07 Green-Mode Fairchld Power Switch for Quasi- Resonant Operation. Featuring FSQ0765RQ. Farichild FSQ0565R Click Oct/07 Green-Mode Fairchld Power Switch for Quasi- Resonant Operation. Featuring FSQ0565RQ, KA431A and FOD817A. Farichild Part Number URL Date Published Reference Design Title Manufacturer
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