升压转换器设计精选：热门产品特性与应用案例

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<div class=WordSection1>立锜提供多样化的升压转换器解决方案，以满足不同应用需求。本篇应用笔记将探讨多款热门升压转换器的主要特性与应用范例，帮助工程师在不同应用中选择最合适的产品，确保系统的高效能与稳定性。</div> <div class=WordSection2><h2 id=“__Bookmark__0”>1 升压转换器的选择考量</h2>在不同应用中，选择合适的升压转换器需要综合考量以下因素：输入输出电压范围、静态电流与功率、控制接口、封装与成本。以下列表为立锜推出的热门升压转换器产品，依据功能与架构分为四大类及相应产品，包括具备旁路开关架构的 RT4803/RT4803A/RT4803B 系列、低静态电流的 RT4823、简易设计的 RT4812，以及高压输出的 RT8581。<table class=MsoTableGrid border=1 cellspacing=0 cellpadding=0 width=1021 style='border-collapse:collapse;border:none'><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;background: #D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'></td><td width=431 colspan=3 style='width:215.7pt;border:solid windowtext 1.0pt; border-left:none;background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>With Bypass MOSFET</td><td width=137 style='width:68.6pt;border:solid windowtext 1.0pt;border-left: none;background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Easy Design</td><td width=132 style='width:65.75pt;border:solid windowtext 1.0pt;border-left: none;background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Low Iq</td><td width=128 style='width:63.8pt;border:solid windowtext 1.0pt;border-left: none;background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>High Vout</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'></td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>RT4803</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>RT4803A</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>RT4803B</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>RT4812</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>RT4823</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; background:#D9D9D9;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>RT8581</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Vin</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V-5.5V</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V-5V</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V-5V</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V-5V</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V-5.5V</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>2.7V-12V</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Vout</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>2.85V-4.4V</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>2.85V-4.4V</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>2.85V-4.4V</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V-5.5V</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>5V</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>4.5V-12.6V</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>I/O</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.2V</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.8V</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>1.2V</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>ISW</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>5A</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>4A</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>4A</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>4A</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>2.15A</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>10A</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>BYP_FET</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Y</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Y</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Y</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>--</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>--</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>--</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>I2C</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Y</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Y</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Y</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>--</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>--</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>--</td></tr><tr style='height:17.0pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>Iq</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>65μA</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>55μA</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>56μA</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>90μA</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>4μA</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>30μA</td></tr><tr style='height:39.7pt'><td width=122 style='width:60.8pt;border:solid windowtext 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>Packages</td><td width=149 style='width:74.55pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>WL-CSP1.67x1.67-16(BSC)</td><td width=140 style='width:70.0pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>WL-CSP1.67x1.67-16(BSC)</td><td width=142 style='width:71.15pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>WL-CSP1.67x1.67-16(BSC)</td><td width=137 style='width:68.6pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>TSOT-23-8(FC)</td><td width=132 style='width:65.75pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>WL-CSP1.3x1.2-9(BSC)</td><td width=128 style='width:63.8pt;border-top:none;border-left:none; border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt'>VQFN2x2.5-11</td></tr></table> <h2 id=“__Bookmark__1”>2 不同类型升压转换器的特性与应用案例</h2><h3>2.1 具备旁路开关架构的升压转换器：RT4803、RT4803A、RT4803B</h3>一般升压转换器在旁路模式 (Bypass Mode) 下运行时，输入电流需要经过电感与上桥 MOSFET (HS_FET) 后才能传输至输出端，导致较高的导通损耗。然而，RT4803 系列产品在旁路模式下，电流仅需通过内建的旁路开关 (BYP_FET) 即可直接输出，从而避免了电感直流电阻 (DCR) 带来的额外损耗，显著降低了导通损耗，并确保输出电压不低于目标值。此外，旁路开关架构可进一步将传统效率从 97% 至 98% 提升至接近 100%，减少功耗与热能产生，提升系统性能与可靠性。RT4803 系列采用小型 CSP 封装，其中RT4803B 的 I/O 电压可低至 1.2V，非常适用于高容量低操作电压特性的硅负极电池 (Si-Anode Battery) 的手机应用模块，如 2G PA、WiFi 模块、音频放大器，或其他移动或可穿戴设备应用。<a class="fancybox" href="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image001_zh-cn.png"><img border=0 width=401 height=159 src="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image001_zh-cn.png" alt="Technical Document Image Preview"></a>图1. 移动设备电源应用范例 <h3>2.2 低静态电流升压转换器：RT4823</h3>RT4823 采用 CSP 小型封装，专为智能手机及小型可穿戴设备设计。以下案例展示其在手机 OTG (On-The-Go) 功能中的应用。当用户将小型风扇、存储设备或手电筒等外部设备连接至 USB 接口时，手机需提供 5V 电压输出。根据 Type-C 标准，此类应用通常要求 5V/1.5A，即 7.5W 的输出功率。RT4823 可满足此需求，并且其静态电流仅为 4μA，特别适合长时间待机的应用场景。此外，RT4823 内建防逆灌 (Reverse Blocking) 保护机制，有效防止外部电压回灌至输入端，提升系统的稳定性与安全性。<a class="fancybox" href="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image002_zh-cn.png"><img border=0 width=594 height=198 id="Picture 5" src="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image002_zh-cn.png" alt="A screenshot of a computer

Description automatically generated"></a>图2. 移动设备 OTG 应用范例 <h3>2.3 简易设计升压转换器：RT4812</h3>RT4812 是一款采用 TSOT-23-8 封装的高性能升压转换器，具备简单易用的设计。通过 FB 引脚可灵活调整输出电压，并可直接通过引脚配置平均输出电流限制阈值，以适应 1A 或 2.1A 两种不同的应用需求。TSOT-23-8 封装具有成本优势，无需通过 PCB 钻孔 (Via) 布线，使其特别适用于单/双层板的成本敏感型应用，如移动电源、无线鼠标等消费性电子产品。<a class="fancybox" href="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image003_zh-cn.png"><img border=0 width=485 height=157 id="Picture 6" src="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image003_zh-cn.png" alt="A screenshot of a computer

Description automatically generated"></a>图3. 光学鼠标应用 <h3>2.4 高输出电压升压转换器：RT8581</h3>RT8581 是一款高输出电压的升压转换器，可为采用先进锂离子电池的系统提供高效、紧凑的电源解决方案，提供高达 20W 的功率输出。RT8581 可从单颗锂离子电池提供稳定的输出电压，并且其内部开关元件具有低导通电阻，重载效率高达 94.5% (Vin = 5V, Vout = 12V, Iout = 1.5A) 。图4 显示了 RT8581 在 NAND Flash 供电中的应用。通过 RT8581 为 VPP 供电，可有效提升 NAND Flash 的写入速度，优化存储性能并提升系统整体性能。此外，RT8581 也可用于音频放大器供电，如图5 所示。<a class="fancybox" href="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image004_zh-cn.png"><img border=0 width=377 height=213 id="Picture 7" src="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image004_zh-cn.png" alt="A screenshot of a computer

Description automatically generated"></a><a name="_Ref193902965">图</a>4. NAND Flash 供电应用<a class="fancybox" href="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image005_zh-cn.jpg"><img border=0 width=463 height=225 id="Picture 8" src="/content/dam/richtek-eds/resources/application-notes/an087/html-images-zh_cn/image005_zh-cn.jpg" alt="A screenshot of a computer

Description automatically generated"></a><a name="_Ref193903408">图</a>5. 音频放大器应用 <h2 id=“__Bookmark__2”>3 结论</h2>立锜提供多样化的升压转换器产品，以满足不同应用场景对功率效率、静态电流、封装尺寸及控制接口的需求。本应用笔记提供各类升压转换器的特性与应用案例，帮助工程师快速选择最合适的解决方案。通过 RT4803 系列的旁路开关架构，可有效降低导通损耗并提升效率；RT4823 以超低静态电流特性，适用于 OTG 及长时间待机应用；RT4812 提供简易设计方案，具有成本优势；而 RT8581 则具备高电压输出能力，能够为高功耗应用如 NAND Flash 及 9W 至 15W 的音频放大器提供稳定电源。工程师可在不同应用中实现最佳的电源管理方案，确保产品在高效能与低功耗之间达到最佳平衡。</div>

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