自发明之前，继电器已使低压信号能够控制高压系统。抗抗性非常低，当今的尊贵机电继电器（EMR）仍然可以找到使用，但是最新的固态继电器（SSR）在终身可靠性，开关速度，功耗，电力消耗和冲击和振动方面都具有很大的优势。
SSRs也提供优势光控继电器(或optical relays), which face achievable-power-transfer limits and are subject to internal LED degradation. SSRs find use in a variety of automotive and industrial applications, including inrush current limiting and insulation-resistance monitoring.
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门驱动器和开关
德州仪器’ SSR lineup includes switches with internal FETs as well as gate drivers for use with external power switches，包括MOSFET，IGBT，硅胶（SIC）MOSFET和硅控制的整流器。他们没有在运营寿命中经历机械降解，这可能超过EMR的寿命为10倍。
这些SSR的切换时间在微秒范围内，比EMR的切换时间快。他们可以在隔离屏障上传递功率和信号，并且不需要单独的隔离次要偏置供应。并且设备可以由微处理器的逻辑输出驱动，从而最大程度地减少对外部控制电路的需求。
Be aware of one caveat: Like all high-speed switches, SSRs can generate EMI. Therefore, when using them, follow EMI design best practices, such as minimizing current loops by keeping printed-circuit-board traces short.
Ti隔离产品具有通过电容或磁性隔离技术实现的基本或增强级别的隔离水平。该公司的隔离产品采用聚酰亚胺或二氧化硅作为绝缘材料，其典型的介电强度为300 VRMS/µm和500 VRMS/µm, respectively. In contrast, EMRs and photorelays often employ air or epoxy as insulation materials, with dielectric strengths of only about 1 VRMS/µm和20 VRMS/µm。
汽车-Qualified Products
New SSR offerings from TI include two automotive-qualified devices: the TPSI3050-Q1, an isolated switch driver with an integrated 10-V gate supply, and the TPSI2140-Q1, a 1,400-V, 50-mA isolated switch. Both devices integrate power and signal isolation across a single isolation barrier using a unique approach that improves reliability while reducing solution size and cost compared with electromechanical relays and solid-state photorelays. In addition, both can disconnect and connect loads through a single isolation barrier in microseconds—compared to milliseconds for electromechanical relays.
The TPSI3050-Q1（图。1）offers inductive reinforced isolation to 5 kVRMSand an operating lifetime that’s 10X longer than that of electromechanical relays. It reduces solution size up to 90% compared to mechanical-relay solutions by integrating an isolated power supply, a digital isolator, and gate driver within the IC package.
TPSI2140-Q1（图2）offers capacitive basic isolation to 3.75 kVRMS, enabling it to achieve time-dependent dielectric breakdown reliability more than 4X higher than that of solid-state photorelays. The SSR reduces solution size by as much as 50% compared to traditional solid-state photorelay solutions by integrating a signal FET and resistors, eliminating the need for a reed relay.
TPSI2140-Q1可以与电池包监视器（例如BQ79631-Q1）一起使用，以检测800V电池管理系统中的绝缘故障。它可以使用<1-MΩ电阻，并且比传统的光层可以承受雪崩的电流超过300％。
新的汽车合格设备是新的SSR投资组合中的第一个，它还将包括用于高压工业应用的IC。
Design Resources
德州仪器offers a variety of resources to help you design with its isolation products, which in addition to SSRs include standalone digital isolators, isolated interface ICs, isolated ADCs, and isolated amplifiers. The resources include PSpice models and evaluation boards as well as detailed application notes and reference designs.
例如，一个申请注意说明了如何将两个TPSI3050隔离开关驱动器叠加以增加栅极驱动电压并最大程度地减少结合IGBT和SIC MOSFET的传导损耗。TPSI3050的浮动次要电源可实现cascode配置（图3），它可以提供高达20 V的闸门驱动电压。
Another application note shows a TPSI3050-Q1 used in a pre-charge circuit to minimize inrush currents in automotive onboard chargers as well as industrial power supplies and power-distribution systems. The solid-state approach enabled by the TPSI3050 renders bulky and fault-prone electromechanical contactors unnecessary. A response time of less than 3 µs allows the TPSI3050 to quickly turn off a switch in case of an overcurrent or overheating condition.
TI的参考设计包括设计指南，原理图，BOMS，组装图，Gerber文件，PCB布局文件和计算器，以帮助确定关键的组件值。一种参考设计实现模拟前端（AFE）进行绝缘监测（图4）。It leverages the TPSI2140-Q1 isolated switch and the AMC3330 reinforced isolated amplifier, which features a ±1-V input and integrated dc-dc converter.
AFE可以监测对称或不对称泄漏电流，并测量与保护地面正面或负高压供应的绝缘耐药性。它需要在热侧不需要外部电源。
其他参考设计显示，在零交叉开关电路以及过度和过电流的保护应用程序中使用的TPSI3050-Q1隔离开关驱动程序。对于每个参考设计，TI都制造了一个完全组装的板进行测试和性能验证。
Conclusion
在汽车和工业应用中使用越来越高的电压的系统需要可靠的隔离，以确保人员和设备的安全。Ti的新型隔离开关和开关驱动器ICS补充Ti的完整隔离产品阵容，以提供最佳的性能和设计灵活性。TI为其隔离组合提供了全面的支持，从模拟模型扩展到参考设计。
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