DC-DC|Evaluation
Loss Factors
2019.03.07
Points of this article
・Losses at specific places that make up the overall circuit losses are increased depending on the operating conditions.
・By understanding the loss factors through the equations for the losses, it is possible to understand what points require attention when changing the specifications or the operating conditions.
In this article, we examine the relationship between operating conditions and loss increases.
Loss Factors
We have explained that losses occur at various places in a power supply circuit; but the losses at specific places making up the total losses of the circuit become higher depending on the operating conditions. Hence it is necessary to understand the factors that increase losses depending on the operating conditions. Below we have summarized loss factors in relation to various conditions. Calculation formulae for losses are also presented, and should help to further clarify the relation between losses and operating conditions.
Loss Factors that Increase with Increasing Load Current
・Conduction losses due to the ON-resistance of the high-side MOSFET
・Conduction losses due to the ON-resistance of the low-side MOSFET
・Conduction losses due to the inductor (coil) DCR
Loss Factors that Increase with Higher Frequencies
・Gate charge losses
Loss Factors that are Affected by Both the Load Current and the Frequency
・Switching losses
・Dead time losses
These are related to modification of the power supply circuit specifications and changes in the operating conditions. If these relationships are understood, it will be possible to understand what points require attention when re-examining the circuit.
【Download Documents】Step-Down DC-DC Converter Examination of Losses
A hand book to study losses of synchronous rectifying step-down converters showing definitions of losses, relations to heat generation, loss equations for places at which losses occur in a circuit, examples of thermal calculation, relations to applications and Losses, and so on.
List of articles related to the「Loss Factors」
- 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
- 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
Download Technical Documents
Basic of Linear Regulators and Switching Regulators
Basic studies for linear regulators and switching regulators as a DC-DC converter.
DC-DC
- Basic
- Design
-
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
- Product Information
- FAQ