DC-DC｜Basic
Switching Regulator Basics
2015.09.03
Switching regulators, due to their high power conversion efficiency and flexibility, have made inroads into a growing number of devices and become the preferred power supply units. Previously, a standard practice for switching power supply units was to purchase completed modules or units. In recent years, however, with the availability of ICs for a wide variety of switching power supplies, the strategy employed by electric circuit designers has shifted to the so-called “on-board design” in which a switching power supply unit is built into the circuit board. That said, it is also a fact of life that the various issues presented by switching power circuits, different from the linear regulator, pose a significant challenge to the designer.
In this installment, focusing on the step-down switching regulator, its basic aspects, such as its operation and functions are explained.
【Download Documents】 Switching Regulator Basics
The basics of step-down switching regulators, including their operation and functions, are explained. Comparison with linear regulators, synchronous rectification and diode rectification, control method, auxiliary functions, etc. are also explained.
DC-DC
Basic
- Operation During Shutdown of a Boost DC-DC Converter
- Linear Regulator Basics
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Switching Regulator Basics
- Types of Switching Regulators
- Advantages vs Disadvantages in Comparison with Linear Regulator
- Supplement－Current Paths during Synchronous Rectifying Step-Down Converter Operation
- Operating Principles of Buck Switching Regulator
- Differences between Synchronous and Nonsynchronous Rectifying DC-DC Conversion
- Control Methods (Voltage Mode, Current Mode, Hysteresis Control)
- Efficiency Improvements at Light Load for the Synchronous Rectifying Type
- Protective and Sequencing Functions
- Considerations on Switching Frequencies
- Behavior when Vin Falls Below Vout
- Supplement－Protective Function: Output Pre-bias Protection
- Seven Representative Power Supply Circuits: From Low-noise to Boost Specs
- Concluding Remarks
- What is a DC/DC Converter?
Design
- Overview of Selection of Inductors and Capacitors for DC-DC Converters
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Overview of DC-DC Converter PCB Layout
- Ringing at switching nodes
- Placement of input capacitors and output diodes
- Placement of Thermal Vias
- Placement of Inductors
- Placement of Output Capacitors
- Feedback Path Wiring
- Ground
- Resistance and Inductance of Copper Foil
- Noise countermeasures: corner wiring, conducted noise, radiated noise
- Noise countermeasures: snubber, bootstrap resistor, gate resistor
- Summary
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PCB Layout of a Step-Up DC-DC Converter – Introduction
- The Importance of PCB Layout Design
- Current Paths in Step-up DC-DC Converters
- PCB Layout Procedure
- Placement of Input Capacitors
- Placement of Output Capacitors and Freewheel Diodes
- Inductor Placement
- Placement of Thermal Vias
- Feedback Path Wiring
- Ground
- Layout for Synchronous Rectification Designs
- Resistance and Inductance of Copper Foil
- Relationship Between Corner Wiring and Noise
- Summary
Evaluation
- Overview of Characteristics and Evaluation Method of Switching Regulators
- How to Read Power Supply IC Datasheets: Cover, Block Diagram, Absolute Maximum Ratings and Recommended Operating Conditions
- Evaluating a Switching Regulator: Output Voltage
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Introduction
- Definitions and Heat Generation
- Losses in Synchronous Rectifying Step-Down Converters
- Conduction Losses in Synchronous Rectifying Step-Down Converters
- Switching Losses in Synchronous Rectifying Step-Down Converters
- Dead Time Losses in Synchronous Rectifying Step-Down Converters
- Controller IC Power Consumption Losses in a Synchronous Rectifying Step-Down Converter
- Gate Charge Losses in a Synchronous Rectifying Step-Down Converter
- Conduction Losses due to the Inductor DCR
- Example of Power Loss Calculation for a Power Supply IC
- Simplified Method of Loss Calculation
- Heat Calculation for Package Selection: Example 1
- Heat Calculation for Package Selection: Example 2
- Loss Factors
- Matters to Consider When Studying Miniaturization by Raising the Switching Frequency
- Important Matters when Studying High Input Voltage Applications
- Important Matters when Studying Large Output Currents Applications: Part 1
- Important Matters when Studying Large Output Currents Applications: Part 2
- Summary
Application
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Important Points in the Design of a Power Supply Using a Linear Regulator
- Typical Application Circuit Examples of Linear Regulator ICs
- Input/output capacitor design and ripple prevention for linear regulator ICs
- How to determine efficiency and Thermal design for linear regulator ICs
- Protection of Linear Regulator IC Terminals
- Soft Starting of a Linear Regulator IC
- Overcurrent Protection（OCP） and Thermal Shutdown（TSD） of Linear Regulator IC
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Important Points in the Design of a Power Supply Using a Floating Type Linear Regulator
- Example of Power Supply Circuit Based on a Floating Type Linear Regulator IC
- Input/output capacitor design and ripple prevention for linear regulator ICs
- How to determine efficiency and Thermal design for Floating Type Linear Regulator ICs
- Terminal protection for linear regulator ICs
- Startup characteristics for linear regulator ICs
- Failure to Start of a Power Supply Using a Linear Regulator, Case 1: Damage to the IC and Peripheral Components Due to Hand-Soldering
- About Parallel Connections of LDO Linear Regulators
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Introduction
- Power Supply Sequence Specification ①: Power Supply Sequence Specifications and Control Block Diagrams
- Power Supply Sequence Specification①: Sequence Operation at Power Turn-on
- Power Supply Sequence Specification①: Sequence Operation at Power Shutoff
- Power Supply Sequence Specification①： Example of Actual Circuit and Component Value Calculations
- Power Supply Sequence Specification①: Example of Actual Operations
- Power Supply Sequence Specification②:Power Supply Sequence Specifications and Control Block Diagrams
- Power Supply Sequence Specification②:Sequence Operation at Power Turn-on
- Power Supply Sequence Specification②: Sequence Operation at Power Shutoff
- Power Supply Sequence Specification②: Example of Actual Circuit and Component Value Calculations
- Power Supply Sequence Specification②: Example of Actual Operations
- Circuits to Implement Power Supply Sequences Using General-Purpose Power Supply ICs ーSummaryー
- Easy Stabilization/Optimization Methods for Linear Regulators – Introduction
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