DC-DC｜Application
Circuits to Implement Power Supply Sequences Using General-Purpose Power Supply ICs ーSummaryー
2023.04.12
This concludes our discussion of “Circuits to Implement Power Supply Sequences Using General-Purpose Power Supply ICs,” which has extended over 11 articles. In this section we have presented two circuit examples that employ general-purpose power supply ICs to constitute three-output power supply circuits provided with sequencing functions. In order to provide a power supply circuit with sequencing functions, a number of methods can be used, including opting for power supply ICs that have sequence functions or using sequencer ICs. Here, we have achieved sequence functions by combining power supply ICs having enable functions with power-good ICs and comparator ICs. In actual design, the optimum method should be chosen taking into comprehensive consideration the details of the control needed, the circuit configuration (complexity, number of components, and so on), the board area, cost, and other factors.
Below are summaries of the key points of the articles, with links to the articles themselves.
Circuits to Implement Power Supply Sequences Using General-Purpose Power Supply ICs ―Introduction―
Key Points of This Article
・For ICs and electronic equipment requiring multiple power supplies, in some cases ordered turn-on and turn-off, or sequence control, is needed.
・In these articles, examples are presented in which general-purpose power supplies and external circuits are used to implement sequence control, without using sequence control ICs or power supply ICs with sequence support functions.
Key Points of This Article
・In sequence ①, power supplies with three supply voltages are turned on in order, and are shut off in the reverse order.
・For design purposes, the function blocks needed to obtain the target operations are considered.
・To achieve sequence ①, three DCDC ICs, four Power Good circuits, and three discharge circuits are used.
Power Supply Sequence Specification ①: Sequence Operation at Power Turn-on
Key Points of This Article
・In Sequence ①, power supplies with three supply voltages are turned on in order, and are shut off in the reverse order.
・In order to aid understanding of the sequence operation, the operations for turn-on of the three power supply systems were presented separately.
Power Supply Sequence Specification ①: Sequence Operation at Power Shutoff
Key Points of This Article
・In sequence ①, power supplies with three supply voltages are turned on in order, and shut off in the reverse order.
・In order to facilitate understanding of sequence operations, the operations at power shutoff for each of the three power supply systems were illustrated in terms of three stages.
Power Supply Sequence Specification①： Example of Actual Circuit and Component Value Calculations
Key Points of This Article
・A circuit to realize the power supply sequence ① consists of 3 DCDC ICs, 4 Power Good circuits, 3 discharge circuits, and diodes.
Power Supply Sequence Specification①: Example of Actual Operations
Key Points of This Article
・Confirm the specifications, circuit operations, and waveforms for power supply sequence ①.
Key Points of This Article
・The specifications of the power supply sequence ② are confirmed.
・A function block diagram to represent the specifications is created.
Power Supply Sequence Specification②: Sequence Operation at Power Turn-on
Key Points of This Article
・In sequence ②, three power supply systems are turned on in order, and are shut off in the same order.
・In order to aid understanding of sequence operation, the operation at the time of turn-on of each of the three power supply systems is shown separately.
Power Supply Sequence Specification②: Sequence Operation at Power Shutoff
Key Points of This Article
・In sequence ②, three power supply systems are turned on in order, and are shut off in the same order.
・In order to aid understanding of sequence operation, the operation at the time of shutoff of each of the three power supply systems is shown separately.
Power Supply Sequence Specification②: Example of Actual Circuit and Component Value Calculations
Key Points of This Article
・A circuit to realize the power supply sequence ② consists of 3 DCDC ICs, 2 Power Good circuits, and 3 discharge circuits.
Power Supply Sequence Specification②: Example of Actual Operations
Key Points of This Article
・The power supply sequence ② specifications, circuit operation, and waveforms are confirmed
DC-DC
Basic
- Operation During Shutdown of a Boost DC-DC Converter
- Linear Regulator Basics
-
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
-
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
-
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
-
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
-
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
-
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
-
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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