Synchronous Step-Down SWIFT™ Converter with Eco-Mode™ <ul><li>Source: Texas Instruments </li></ul>
Introduction <ul><li>Purpose </li></ul><ul><ul><li>An   Introduction   to   Synchronous   Step-Down   SWIFT™   Converter  ...
Features of TPS5442X Device  <ul><li>D-CAP2™   Mode   Enables   Fast   Transient   Response   </li></ul><ul><li>Low   Outp...
Functional Block Diagram
Design Guide <ul><li>To begin the design process, you must know a few application parameters: </li></ul><ul><ul><li>Input ...
Output Voltage Resistors Selection
Output Filter Selection <ul><li>The   output   filter   used   with   the   TPS54426   is   an   LC   circuit.   This   LC...
Input Capacitor Selection <ul><li>Bootstrap Capacitor Selection: </li></ul><ul><li>A 0.1 mF ceramic capacitor must be conn...
Efficiency of TPS5442x Device  Efficiency Light Load Efficiency
Load Transient Response of TPS5442x Device  Load Transient Response Output Voltage Ripple
TPS54426EVM-608 4-A, SWIFT™ Regulator  Evaluation Board Schematic TPS54426EVM-608 Schematic Diagram
Start Up of TPS54426 Device  Start Up Relative to Enable TPS54426 Start Up
Applications of TPS5442X Device  <ul><li>Wide Range of Applications for Low Voltage System </li></ul><ul><ul><li>Digital T...
Additional Resource <ul><li>For ordering  TPS5442x , please click the  part list  or </li></ul><ul><li>Call our sales hotl...
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Synchronous Step-Down SWIFT™ Converter with Eco-Mode™

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An Introduction to Synchronous Step-Down SWIFT™ Converter with Eco-Mode

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  • Welcome to the training module on 4.5V to 18V Input, 4-A Synchronous Step-Down SWIFT™ Converter with Eco-Mode™
  • This training module will introduce to Synchronous Step-Down SWIFT™ Converter with Eco-Mode .
  • The TPS5442x series, including TPS54425 and TPS54426, are adaptive on-time D-CAP2™ mode synchronous buck converters. The TPS5442x enables system designers to complete the suite of various end equipment’s power bus regulators with a cost effective, low component count, low standby current solution. The main control loop for the TPS5442x uses the D-CAP2™ mode control which provides a very fast transient response with no external compensation components. The TPS54426’s adaptive on-time control supports seamless transition between PWM mode at higher load conditions and Eco-mode™ operation at light loads. Eco-mode™ allows the TPS54426 to maintain high efficiency during lighter load conditions. Both devices operate from 4.5-V to 18-V VIN input. The output voltage can be programmed between 0.76 to 5.5V.
  • Here shows the functional block diagram of the TPS54426. The TPS54426 is a single, adaptive on-time D-CAP2™ mode synchronous buck converter requiring a very low external component count. The D-CAP2™ control circuit is optimized for low ESR output capacitors such as POSCAP, SP-CAP or ceramic types and features fast transient response with no external compensation. The switching frequency is internally set at a nominal 700 kHz. The high-side and low-side switching MOSFETs are incorporated inside the TPS54426 package along with the gate drive circuitry.
  • This page gives information on design parameter of TPS5442x. The output voltage is set with a resistor divider from the output node to the VFB pin. The output filter used with the TPS54426 is an LC circuit (L1 and C8 || C9). The TPS54426 requires an input decoupling capacitor and a bulk capacitor is needed depending on the application. A 0.1 µ F ceramic capacitor must be connected between the VBST to SW pin for proper operation. A 1.0 µ F ceramic capacitor must be connected between the VREG5 to GND pin for proper operation.
  • The output voltage is set with a resistor divider from the output node to the VFB pin. It is recommended to use 1% tolerance or better divider resistors. To change the output voltage, it is necessary to change the value of resistor R1. Changing the value of R1 can change the output voltage above 0.765V. The value of R1 for a specific output voltage can be calculated using the given equation.
  • At low frequencies, the overall loop gain is set by the output set-point resistor divider network and the internal gain of the TPS54426. The low frequency phase is 180 degrees. At the output filter pole frequency, the gain rolls off at a -40 dB per decade rate and the phase drops rapidly. The inductor saturation current rating must be greater than the calculated peak current and the RMS or heating current rating must be greater than the calculated RMS current. Use 700 kHz for f SW .
  • The TPS54426 requires an input decoupling capacitor and a bulk capacitor is needed depending on the application. A ceramic capacitor over 10 uF. is recommended for the decoupling capacitor. An additional 0.1 μF capacitor from pin 14 to ground is recommended to improve the stability of the over-current limit function. The capacitor voltage rating needs to be greater than the maximum input voltage.
  • This page shows the efficiency and efficiency at light loads for the TPS54426 at an ambient temperature of 25°C.
  • The TPS54426 responses to load transient and output voltage ripple is shown in this page. The current step is from 500 mA to 1.5 A (25% to 75% of rated load). Total peak-to-peak output voltage variation is also shown . The output current is the rated full load of 2A.
  • This page shows Evaluation board schematic diagram. The high-side and low-side switching MOSFETs are incorporated inside the TPS54426 package along with the gate drive circuitry. The low drain-to-source on resistance of the MOSFETs allow the TPS54426 to achieve high efficiencies and helps keep the junction temperature low at high output currents. The TPS54426 also has an auto-skip Eco-mode™ to enable higher efficiency at light loads.
  • This page shows startup sequence of TPS54426 device. The device features an adjustable soft start time and a power good function. The device operates from 4.5-V to 18-V VIN input. The output voltage can be programmed between 0.76 V and 5.5 V.
  • This page gives application information where TPS5442X device can be used. It can be used in Digital TV power supply, HD blue ray disc player, networking home terminal, digital STB
  • Thank you for taking the time to view this presentation on “ [ Synchronous Step-Down SWIFT™ Converter with Eco-Mode ]” . If you would like to learn more or go on to purchase some of these devices, you may either click on the part list link right beside the play button on the TechCast portal, or simply call our sales hotline. For more technical information you may either visit the [ Texas Instruments ] site, or if you would prefer to speak to someone live, please call our hotline number, or even use our ‘live chat’ online facility. You may visit element14 e-community to post your questions.
  • Synchronous Step-Down SWIFT™ Converter with Eco-Mode™

    1. 1. Synchronous Step-Down SWIFT™ Converter with Eco-Mode™ <ul><li>Source: Texas Instruments </li></ul>
    2. 2. Introduction <ul><li>Purpose </li></ul><ul><ul><li>An Introduction to Synchronous Step-Down SWIFT™ Converter with Eco-Mode </li></ul></ul><ul><li>Outline </li></ul><ul><ul><li>Key Features and application </li></ul></ul><ul><ul><li>Block Diagram Description </li></ul></ul><ul><ul><li>Design guidelines, output voltage resistor selection </li></ul></ul><ul><ul><li>Characteristics, Efficiency, load transient response and Start-up </li></ul></ul><ul><ul><li>output capacitor selection and output filter selection </li></ul></ul><ul><li>Content </li></ul><ul><ul><li>14 pages </li></ul></ul>
    3. 3. Features of TPS5442X Device <ul><li>D-CAP2™ Mode Enables Fast Transient Response </li></ul><ul><li>Low Output Ripple and Allows Ceramic Output Capacitor </li></ul><ul><li>Wide V IN Input Voltage Range: 4.5 V to 18 V </li></ul><ul><li>Output Voltage Range: 0.76 V to 5.5 V </li></ul><ul><li>Highly Efficient Integrated FET’s Optimized for Lower Duty Cycle Applications – 65 m Ω (High Side) and 55 m Ω (Low Side) </li></ul><ul><li>High Efficiency, less than 10 µA at shutdown </li></ul><ul><li>High Initial Bandgap Reference Accuracy </li></ul><ul><li>Adjustable Soft Start </li></ul><ul><li>Pre-Biased Soft Start </li></ul><ul><li>700-kHz Switching Frequency (fSW) </li></ul><ul><li>Cycle By Cycle Over Current Limit </li></ul><ul><li>Power Good Output </li></ul><ul><li>Auto-Skip Eco-mode™ for High Efficiency at Light Load (TPS54426 only) </li></ul>
    4. 4. Functional Block Diagram
    5. 5. Design Guide <ul><li>To begin the design process, you must know a few application parameters: </li></ul><ul><ul><li>Input voltage range </li></ul></ul><ul><ul><li>Output voltage </li></ul></ul><ul><ul><li>Output current </li></ul></ul><ul><ul><li>Output voltage ripple </li></ul></ul><ul><ul><li>Input voltage ripple </li></ul></ul>
    6. 6. Output Voltage Resistors Selection
    7. 7. Output Filter Selection <ul><li>The output filter used with the TPS54426 is an LC circuit. This LC filter has double pole at: </li></ul><ul><li>The inductor and capacitor selected for the output filter must be selected so that the double pole is located below the high frequency zero </li></ul>
    8. 8. Input Capacitor Selection <ul><li>Bootstrap Capacitor Selection: </li></ul><ul><li>A 0.1 mF ceramic capacitor must be connected between the VBST to SW pin for proper operation. It is recommended to use a ceramic capacitor </li></ul><ul><li>VREG5 Capacitor Selection </li></ul><ul><li>A 1.0 mF ceramic capacitor must be connected between the VREG5 to GND pin for proper operation. It is recommended to use a ceramic capacitor. </li></ul>
    9. 9. Efficiency of TPS5442x Device Efficiency Light Load Efficiency
    10. 10. Load Transient Response of TPS5442x Device Load Transient Response Output Voltage Ripple
    11. 11. TPS54426EVM-608 4-A, SWIFT™ Regulator Evaluation Board Schematic TPS54426EVM-608 Schematic Diagram
    12. 12. Start Up of TPS54426 Device Start Up Relative to Enable TPS54426 Start Up
    13. 13. Applications of TPS5442X Device <ul><li>Wide Range of Applications for Low Voltage System </li></ul><ul><ul><li>Digital TV Power Supply </li></ul></ul><ul><ul><li>High Definition Blu-ray Disc™ Players </li></ul></ul><ul><ul><li>Networking Home Terminal </li></ul></ul><ul><ul><li>Digital Set Top Box (STB) </li></ul></ul>
    14. 14. Additional Resource <ul><li>For ordering TPS5442x , please click the part list or </li></ul><ul><li>Call our sales hotline </li></ul><ul><li>For more product information go to </li></ul><ul><ul><li>http://focus.ti.com/docs/prod/folders/print/tps54426.html </li></ul></ul><ul><li>Visit element14 to post your question </li></ul><ul><ul><li> www.element-14.com </li></ul></ul><ul><li>For additional inquires contact our technical service hotline or even use our “Live Technical Chat” online facility </li></ul>

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