Table of Contents Global Synchronous Buck Converter Market Research Report 2020, Forecast to 2025 1 Market Overview 1.1 Synchronous Buck Converter Definition 1.1.1 Analysis of Macroeconomic Indicators 1.1.2 Years Considered 1.2 Synchronous Buck Converter Segment by Type 1.2.1 AC Quad-phase Synchronous Buck Converter 1.2.2 DC Quad-phase Synchronous Buck Converter 1.3 Market Analysis by Application 1.3.1 Industry 1.3.2 Medical 1.3.3 Home Use 1.3.4 Others 1.4 Overview of Global Synchronous Buck Converter Market 1.4.1 Global Synchronous Buck Converter Revenue (2015-2025) 1.4.2 Global Synchronous Buck Converter Production and Capacity (2015-2025) 1.4.3 North America Synchronous Buck Converter Status and Prospect (2015-2025) 1.4.4 Europe Synchronous Buck Converter Status and Prospect (2015-2025) 1.4.5 Japan Synchronous Buck Converter Status and Prospect (2014-2025) 1.4.6 China Synchronous Buck Converter Status and Prospect (2015-2025) 1.5 Market Dynamics 1.5.1 Market Opportunities 1.5.2 Market Risk 1.5.3 Market Driving Force 1.5.4 Porter's Five Forces Analysis 1.5.5 SWOT Analysis 1.6 Coronavirus Disease 2019 (Covid-19): Synchronous Buck Converter Industry Impact 1.6.1 How the Covid-19 is Affecting the Synchronous Buck Converter Industry 1.6.2 Synchronous Buck Converter Business Impact Assessment - Covid-19 1.6.3 Market Trends and Synchronous Buck Converter Potential Opportunities in the COVID-19 Landscape 1.6.4 Measures / Proposal against Covid-19 2 Global Synchronous Buck Converter Market Competition by Manufacturer 2.1 Global Synchronous Buck Converter Sales and Market Share by Manufacturer (2018-2020) 2.2 Global Synchronous Buck Converter Revenue and Market Share by Manufacturer (2018-2020) 2.3 Global Synchronous Buck Converter Industry Concentration Ratio (CR5 and HHI) 2.4 Top 5 Synchronous Buck Converter Manufacturer Market Share 2.5 Top 10 Synchronous Buck Converter Manufacturer Market Share 2.6 Date of Key Manufacturers Enter into Synchronous Buck Converter Market 2.7 Key Manufacturers Synchronous Buck Converter Product Offered 2.8 Mergers & Acquisitions Planning 3 Analysis of Synchronous Buck Converter Industry Key Manufacturers 3.1 Texas Instruments 3.1.1 Company Details 3.1.2 Product Information 3.1.3 Texas Instruments Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.1.4 Main Business Overview 3.1.5 Texas Instruments News 3.2 Analog Devices 3.2.1 Company Details 3.2.2 Product Information 3.2.3 Analog Devices Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.2.4 Main Business Overview 3.2.5 Analog Devices News 3.3 Infineon Technologies 3.3.1 Company Details 3.3.2 Product Information 3.3.3 Infineon Technologies Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.3.4 Main Business Overview 3.3.5 Infineon Technologies News 3.4 STMicroelectronics 3.4.1 Company Details 3.4.2 Product Information 3.4.3 STMicroelectronics Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.4.4 Main Business Overview 3.4.5 STMicroelectronics News 3.5 Eaton 3.5.1 Company Details 3.5.2 Product Information 3.5.3 Eaton Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.5.4 Main Business Overview 3.5.5 Eaton News 3.6 ROHM Semiconductor 3.6.1 Company Details 3.6.2 Product Information 3.6.3 ROHM Semiconductor Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.6.4 Main Business Overview 3.6.5 ROHM Semiconductor News 3.7 RICOH Electronics 3.7.1 Company Details 3.7.2 Product Information 3.7.3 RICOH Electronics Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.7.4 Main Business Overview 3.7.5 RICOH Electronics News 3.8 Cypress Semiconductor 3.8.1 Company Details 3.8.2 Product Information 3.8.3 Cypress Semiconductor Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.8.4 Main Business Overview 3.8.5 Cypress Semiconductor News 3.9 Maxim Integrated 3.9.1 Company Details 3.9.2 Product Information 3.9.3 Maxim Integrated Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.9.4 Main Business Overview 3.9.5 Maxim Integrated News 3.10 Microchip 3.10.1 Company Details 3.10.2 Product Information 3.10.3 Microchip Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.10.4 Main Business Overview 3.10.5 Microchip News 3.11 ON Semiconductor 3.11.1 Company Details 3.11.2 Product Information 3.11.3 ON Semiconductor Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.11.4 Main Business Overview 3.11.5 ON Semiconductor News 3.12 Vicor 3.12.1 Company Details 3.12.2 Product Information 3.12.3 Vicor Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.12.4 Main Business Overview 3.12.5 Vicor News 3.13 Semtech 3.13.1 Company Details 3.13.2 Product Information 3.13.3 Semtech Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.13.4 Main Business Overview 3.13.5 Semtech News 3.14 Torex Semiconductor 3.14.1 Company Details 3.14.2 Product Information 3.14.3 Torex Semiconductor Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.14.4 Main Business Overview 3.14.5 Torex Semiconductor News 3.15 Intersil 3.15.1 Company Details 3.15.2 Product Information 3.15.3 Intersil Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.15.4 Main Business Overview 3.15.5 Intersil News 3.16 Diodes 3.16.1 Company Details 3.16.2 Product Information 3.16.3 Diodes Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.16.4 Main Business Overview 3.16.5 Diodes News 3.17 Toshiba 3.17.1 Company Details 3.17.2 Product Information 3.17.3 Toshiba Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.17.4 Main Business Overview 3.17.5 Toshiba News 3.18 Vishay Semiconductor 3.18.1 Company Details 3.18.2 Product Information 3.18.3 Vishay Semiconductor Synchronous Buck Converter Production, Price, Cost, Gross Margin, and Revenue (2018-2020) 3.18.4 Main Business Overview 3.18.5 Vishay Semiconductor News 4 Global Synchronous Buck Converter Market Size Categorized by Regions (2015-2020) 4.1 Global Synchronous Buck Converter Sales Market Share by Region 4.2 Global Synchronous Buck Converter Revenue Market Share by Region (2015-2019) 4.3 Global Synchronous Buck Converter Sales, Revenue, Price and Gross Margin (2015-2020) 4.4 North America Synchronous Buck Converter Market Size Detail 4.4.1 North America Synchronous Buck Converter Sales Growth Rate (2015-2020) 4.4.2 North America Synchronous Buck Converter Sales, Revenue, Price and Gross Margin (2015-2020) 4.5 Europe Synchronous Buck Converter Market Size Detail 4.5.1 Europe Synchronous Buck Converter Sales Growth Rate (2015-2020) 4.5.2 Europe Synchronous Buck Converter Sales, Revenue, Price and Gross Margin (2015-2020) 4.6 Japan Synchronous Buck Converter Market Size Detail 4.6.1 Japan Synchronous Buck Converter Sales Growth Rate (2015-2020) 4.6.2 Japan Synchronous Buck Converter Sales, Revenue, Price and Gross Margin (2015-2020) 4.7 China Synchronous Buck Converter Market Size Detail 4.7.1 China Synchronous Buck Converter Sales Growth Rate (2015-2020) 4.7.2 China Synchronous Buck Converter Sales, Revenue, Price and Gross Margin (2015-2020) 5 Global Synchronous Buck Converter Market Segment by Type 5.1 Global Synchronous Buck Converter Revenue, Sales and Market Share by Type (2015-2020) 5.1.1 Global Synchronous Buck Converter Sales and Market Share by Type (2015-2020) 5.1.2 Global Synchronous Buck Converter Revenue and Market Share by Type (2015-2020) 5.2 AC Quad-phase Synchronous Buck Converter Sales Growth Rate and Price 5.2.1 Global AC Quad-phase Synchronous Buck Converter Sales Growth Rate (2015-2020) 5.2.2 Global AC Quad-phase Synchronous Buck Converter Price (2015-2020) 5.3 DC Quad-phase Synchronous Buck Converter Sales Growth Rate and Price 5.3.1 Global DC Quad-phase Synchronous Buck Converter Sales Growth Rate (2015-2020) 5.3.2 Global DC Quad-phase Synchronous Buck Converter Price (2015-2020) 6 Global Synchronous Buck Converter Market Segment by Application 6.1 Global Synchronous Buck Converter Sales Market Share by Application (2015-2020) 6.2 Industry Sales Growth Rate (2015-2020) 6.3 Medical Sales Growth Rate (2015-2020) 6.4 Home Use Sales Growth Rate (2015-2020) 6.5 Others Sales Growth Rate (2015-2020) 7 Synchronous Buck Converter Related Market Analysis 7.1 Upstream Analysis 7.1.1 Macro Analysis of Upstream Markets 7.1.2 Key Players in Upstream Markets 7.1.3 Upstream Market Trend Analysis 7.1.4 Synchronous Buck Converter Manufacturing Cost Analysis 7.2 Downstream Market Analysis 7.2.1 Macro Analysis of Down Markets 7.2.2 Key Players in Down Markets 7.2.3 Downstream Market Trend Analysis 7.2.4 Sales Channel, Distributors, Traders and Dealers 8 Global Synchronous Buck Converter Market Forecast 8.1 Global Synchronous Buck Converter Sales, Revenue Forecast 8.1.1 Global Synchronous Buck Converter Sales Growth Rate Forecast (2020-2025) 8.1.2 Global Synchronous Buck Converter Revenue and Growth Rate Forecast (2020-2025) 8.1.3 Global Synchronous Buck Converter Price and Trend Forecast (2020-2025) 8.2 Global Synchronous Buck Converter Sales Forecast by Region (2020-2025) 8.2.1 North America Synchronous Buck Converter Sales, Revenue Forecast (2020-2025) 8.2.2 Europe Synchronous Buck Converter Sales, Revenue Forecast (2020-2025) 8.2.3 Japan Synchronous Buck Converter Production, Revenue Forecast (2020-2025) 8.2.4 China Synchronous Buck Converter Production, Revenue Forecast (2020-2025) 9 Research Findings and Conclusion 10 Appendix

List of Tables and Figures Figure Synchronous Buck Converter Picture Table Global Synchronous Buck Converter Sales by Type Figure Global Sales Market Share of Synchronous Buck Converter by Product Type in 2019 Table Breakdown of Synchronous Buck Converter by Company Type (Tier 1, Tier 2 and Tier 3) Figure Synchronous Buck Converter Market Share by Company Type (Tier 1, Tier 2 and Tier 3) Figure AC Quad-phase Synchronous Buck Converter Picture Figure DC Quad-phase Synchronous Buck Converter Picture Table Global Synchronous Buck Converter Sales by Application Figure Global Synchronous Buck Converter Sales Market Share by Application in 2019 Figure Industry Picture Figure Medical Picture Figure Home Use Picture Figure Others Picture Table Synchronous Buck Converter Market Size Comparison by Region (2019-2025) (K Units) & (Million US$) Figure Global Synchronous Buck Converter Revenue (Million US$) (2015-2025) Figure Global Synchronous Buck Converter Production (K Units) (2015-2025) Figure North America Synchronous Buck Converter Revenue (Million US$) Growth Rate (2015-2025) Figure Europe Synchronous Buck Converter Revenue (Million US$) Growth Rate (2015-2025) Figure Japan Synchronous Buck Converter Revenue (Million US$) Growth Rate (2014-2025) Figure China Synchronous Buck Converter Revenue (Million US$) Growth Rate (2015-2025) Table Market Opportunities in Next Few Years Table Market Risks Analysis Table Market Drivers Figure Porter's Five Forces Analysis Table SWOT Analysis Table Global Synchronous Buck Converter Sales by Manufacturer (2018-2020) Figure Global Synchronous Buck Converter Sales Market Share by Manufacturer in 2019 Table Global Synchronous Buck Converter Revenue by Manufacturer (2018-2020) Figure Global Synchronous Buck Converter Revenue Market Share by Manufacturer in 2019 Table Global Synchronous Buck Converter Manufacturers Market Concentration Ratio (CR5 and HHI) Figure Top 5 Synchronous Buck Converter Manufacturer (Revenue) Market Share in 2019 Figure Top 10 Synchronous Buck Converter Manufacturer (Revenue) Market Share in 2019 Table Date of Key Manufacturers Enter into Synchronous Buck Converter Market Table Key Manufacturers Synchronous Buck Converter Product Type Table Mergers & Acquisitions Planning Table Texas Instruments Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Texas Instruments Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Texas Instruments Synchronous Buck Converter Market Share (2018-2020) Table Texas Instruments Main Business Table Texas Instruments Recent Development Table Analog Devices Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Analog Devices Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Analog Devices Synchronous Buck Converter Market Share (2018-2020) Table Analog Devices Main Business Table Analog Devices Recent Development Table Infineon Technologies Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Infineon Technologies Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Infineon Technologies Synchronous Buck Converter Market Share (2018-2020) Table Infineon Technologies Main Business Table Infineon Technologies Recent Development Table STMicroelectronics Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of STMicroelectronics Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure STMicroelectronics Synchronous Buck Converter Market Share (2018-2020) Table STMicroelectronics Main Business Table STMicroelectronics Recent Development Table Eaton Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Eaton Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Eaton Synchronous Buck Converter Market Share (2018-2020) Table Eaton Main Business Table Eaton Recent Development Table ROHM Semiconductor Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of ROHM Semiconductor Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure ROHM Semiconductor Synchronous Buck Converter Market Share (2018-2020) Table ROHM Semiconductor Main Business Table ROHM Semiconductor Recent Development Table RICOH Electronics Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of RICOH Electronics Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure RICOH Electronics Synchronous Buck Converter Market Share (2018-2020) Table RICOH Electronics Main Business Table RICOH Electronics Recent Development Table Cypress Semiconductor Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Cypress Semiconductor Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Cypress Semiconductor Synchronous Buck Converter Market Share (2018-2020) Table Cypress Semiconductor Main Business Table Cypress Semiconductor Recent Development Table Maxim Integrated Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Maxim Integrated Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Maxim Integrated Synchronous Buck Converter Market Share (2018-2020) Table Maxim Integrated Main Business Table Maxim Integrated Recent Development Table Microchip Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Microchip Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Microchip Synchronous Buck Converter Market Share (2018-2020) Table Microchip Main Business Table Microchip Recent Development Table ON Semiconductor Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of ON Semiconductor Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure ON Semiconductor Synchronous Buck Converter Market Share (2018-2020) Table ON Semiconductor Main Business Table ON Semiconductor Recent Development Table Vicor Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Vicor Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Vicor Synchronous Buck Converter Market Share (2018-2020) Table Vicor Main Business Table Vicor Recent Development Table Semtech Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Semtech Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Semtech Synchronous Buck Converter Market Share (2018-2020) Table Semtech Main Business Table Semtech Recent Development Table Torex Semiconductor Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Torex Semiconductor Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Torex Semiconductor Synchronous Buck Converter Market Share (2018-2020) Table Torex Semiconductor Main Business Table Torex Semiconductor Recent Development Table Intersil Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Intersil Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Intersil Synchronous Buck Converter Market Share (2018-2020) Table Intersil Main Business Table Intersil Recent Development Table Diodes Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Diodes Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Diodes Synchronous Buck Converter Market Share (2018-2020) Table Diodes Main Business Table Diodes Recent Development Table Toshiba Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Toshiba Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Toshiba Synchronous Buck Converter Market Share (2018-2020) Table Toshiba Main Business Table Toshiba Recent Development Table Vishay Semiconductor Company Profile Figure Synchronous Buck Converter Product Picture and Specifications of Vishay Semiconductor Table Synchronous Buck Converter Production, Price, Revenue and Gross Margin of 2018-2020 Figure Vishay Semiconductor Synchronous Buck Converter Market Share (2018-2020) Table Vishay Semiconductor Main Business Table Vishay Semiconductor Recent Development Table Global Synchronous Buck Converter Sales (K Units) by Region (2015-2020) Table Global Synchronous Buck Converter Sales Market Share by Region (2015-2019) Figure Global Synchronous Buck Converter Sales Market Share by Region (2015-2019) Figure Global Synchronous Buck Converter Sales Market Share by Region in 2018 Table Global Synchronous Buck Converter Revenue (Million US$) by Region (2015-2020) Table Global Synchronous Buck Converter Revenue Market Share by Region (2015-2020) Figure Global Synchronous Buck Converter Revenue Market Share by Region (2015-2020) Figure Global Synchronous Buck Converter Revenue Market Share by Region in 2019 Table Global Synchronous Buck Converter Sales (K Units), Revenue (Million US$), Price (USD/Unit) and Gross Margin (2015-2020) Figure North America Synchronous Buck Converter Sales (K Units) Growth Rate (2015-2020) Figure Europe Synchronous Buck Converter Sales (K Units) Growth Rate (2015-2020) Table Europe Synchronous Buck Converter Sales (K Units), Revenue (Million US$), Price (USD/Unit) and Gross Margin (2015-2020) Figure Japan Synchronous Buck Converter Sales (K Units) Growth Rate (2015-2020) Table Japan Synchronous Buck Converter Sales (K Units), Revenue (Million US$), Price (USD/Unit) and Gross Margin (2015-2020) Figure China Synchronous Buck Converter Sales (K Units) Growth Rate (2015-2020) Table China Synchronous Buck Converter Sales (K Units), Revenue (Million US$), Price (USD/Unit) and Gross Margin (2015-2020) Table Global Synchronous Buck Converter Sales by Type (2015-2020) Table Global Synchronous Buck Converter Sales Market Share by Type (2015-2020) Figure Global Synchronous Buck Converter Sales Market Share by Type in 2019 Table Global Synchronous Buck Converter Revenue by Type (2015-2020) Table Global Synchronous Buck Converter Revenue Market Share by Type (2015-2020) Figure Global Synchronous Buck Converter Revenue Market Share by Type in 2019 Figure Global AC Quad-phase Synchronous Buck Converter Sales Growth Rate (2015-2025) Figure Global AC Quad-phase Synchronous Buck Converter Price (2015-2020) Figure Global DC Quad-phase Synchronous Buck Converter Sales Growth Rate (2015-2025) Figure Global DC Quad-phase Synchronous Buck Converter Price (2015-2020) Table Global Synchronous Buck Converter Sales Market Share by Application (2015-2020) Figure Global Synchronous Buck Converter Sales Market Share by Application in 2019 Figure Global Industry Sales Growth Rate (2015-2025) Figure Global Medical Sales Growth Rate (2015-2025) Figure Global Home Use Sales Growth Rate (2015-2025) Figure Global Others Sales Growth Rate (2015-2025) Table Key Players of Upstream Markets Table Key Raw Materials Figure Price Trend of Key Raw Materials Table Key Suppliers of Raw Materials Figure Manufacturing Cost Structure of Synchronous Buck Converter Table Key Players of Downstream Markets Figure Sales Channel Figure Global Synchronous Buck Converter Production (K Units) Growth Rate Forecast (2020-2025) Figure Global Synchronous Buck Converter Revenue (Million US$) Growth Rate Forecast (2020-2025) Figure Global Synchronous Buck Converter Price and Trend Forecast (2020-2025) Table Global Synchronous Buck Converter Sales (K Units) Forecast by Region (2020-2025) Figure Global Synchronous Buck Converter Production Market Share Forecast by Region (2020-2025) Figure North America Synchronous Buck Converter Sales (K Units) Growth Rate Forecast (2020-2025) Figure North America Synchronous Buck Converter Revenue (Million US$) Growth Rate Forecast (2020-2025) Figure Europe Synchronous Buck Converter Sales (K Units) Growth Rate Forecast (2020-2025) Figure Europe Synchronous Buck Converter Revenue (Million US$) Growth Rate Forecast (2020-2025) Figure Japan Synchronous Buck Converter Production (K Units) Growth Rate Forecast (2020-2025) Figure Japan Synchronous Buck Converter Revenue (Million US$) Growth Rate Forecast (2020-2025) Figure China Synchronous Buck Converter Production (K Units) Growth Rate Forecast (2020-2025) Figure China Synchronous Buck Converter Revenue (Million US$) Growth Rate Forecast (2020-2025) Figure Methodology/Research Approach Figure Market Size Estimation Figure Author List

Texas Instruments Analog Devices Infineon Technologies STMicroelectronics Eaton ROHM Semiconductor RICOH Electronics Cypress Semiconductor Maxim Integrated Microchip ON Semiconductor Vicor Semtech Torex Semiconductor Intersil Diodes