Solid-state relays – TPSI3050-Q1 & TPSI2140-Q1

Application for HV switching solid-state relays

Over the past few decades, the utilization of PCBAs and electronics has grown exponentially. In most cases, these circuits and devices operate on low voltages, which means they pose a low threat to personnel or users.

In contrast, high voltage systems present challenges, including increased safety concerns if anyone comes in contact with HV system components. Physical damage to boards, cables, connectors, and associated electronic and electrical systems can also occur. As a result, relays have often been used to control high voltage system operation and help ensure safe operation.

Traditional electromechanical relays, often used for HV applications, have drawbacks that can result in contingencies such as system operational degradation, damage to system components, and even physical harm to personnel or users. The TPSI3050-Q1 and TPSI2140-Q1 solid-state relays by Texas Instruments offer solutions to these challenges.

High Voltage Electronic Switching Systems

Before the arrival of solid-state devices, there was a time when vacuum tubes were used to perform switching operations. By today’s standards, these elements were slow and heated up to the point of being hot to the touch. Additionally, these devices would explode if current limitations were exceeded.

Relays were a definite improvement, as they greatly limited the safety concerns associated with switching high voltage circuitry. However, there are still challenges that must be mitigated for common HV switching applications, as shown below.

HV Electronic Switching Applications and Challenges
Applications Challenges

Energy Storage Systems (ESS)

 Switchgear (Circuit Breakers)

Solar Energy
Power Conversion System (PCS)


Pre-charge of HV capacitors

Discharge of HV capacitors







Pre-charge of HV capacitors

Discharge of HV capacitors

Insulation resistance monitoring

AEC-Q100 component qualification

Systems which use high voltage components often need a pre-charge circuit to limit inrush current into downstream loads. Similarly, any high voltage capacitors may need to be safely discharged once the system is turned off. In automotive vehicles, switches are used to monitor the insulation of high voltage cables or wires and ensure passenger safety from any potential HV exposure.

Using Solid-state relays to Improve HV System Performance

Mechanical relays depend on coils or springs whose stiffness can degrade with usage, resulting in slower switching times. Relay sticking can occur, where contacts are fused together due to excessive current. These operational issues are eliminated by employing solid-state relays (SSRs).

TI has a long history of building advanced solid-state devices, which includes the TPSI3050-Q1 and TPSI2140-Q1. These SSRs successfully address the challenges for HV switching systems and have the following attributes.


  • Small package size provides installation flexibility.
  • Power and signal isolation is fully integrated.
  • Cost savings of up to 50% (w.r.t. comparable electromechanical relays or contractors.

Below is an example of isolation of power and signal using the TPSI3050-Q1.

Example of signal and power isolation with TPSI3050-Q1 SSR

TPSI3050-Q1 isolation example

The TPSI3050-Q1 above and the TPSI2140-Q1 solid-state relays are great electronic component options for industrial applications and automotive systems, such as EVs. These SSRs deliver the best isolation technology for comparable devices used in up to 1200V applications and can improve overall safety for example in battery management systems (BMS).

How to Optimize TPSI3050-Q1 and TPSI2140-Q1 Designs

The attributes and capabilities of the TPSI3050-Q1 and TPSI2140-Q1 are well suited for high voltage industrial applications. However, these SSRs excel in advanced automotive systems like EVs, including hybrids (HEVs) and plug-ins (PHEVs).  However, it is essential that your development include accurate design data and information and this information be readily accessible from a source where the quality of your UX is a priority.

If you’re looking for CAD models for common components or advanced parts, such as the TPSI3050-Q1 and TPSI2140-Q1 SSRs that improve performance for high-voltage applications, Ultra Librarian helps by compiling all your sourcing and CAD information in one place. Working with Ultra Librarian sets up your team for success to ensure streamlined and error-free design, production, and sourcing. Register today for free.


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