SBOA618 December   2025 TMCS1126

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Current Ratings and Thermal
    1. 2.1 Current Ratings
    2. 2.2 Effects of PCB and Layout
  6. 3Accuracy
  7. 4Bandwidth, Response Time and Propagation Delay
    1. 4.1 Bandwidth
    2. 4.2 Response Time
    3. 4.3 Propagation Delay
  8. 5Lightning and Surge
    1. 5.1 Knowing Lighting and SPD in Solar
    2. 5.2 Understanding IEC 61643-32
    3. 5.3 Understanding IEC 61643-11
    4. 5.4 Surge Requirements in Solar Systems
    5. 5.5 Challenges and Designs for In-Package Hall Sensor
  9. 6Isolation and Reliability
  10. 7Summary
  11. 8References

6 Isolation and Reliability

Figure 6-1 shows a typical isolation design of a string inverter. Usually, a 2-stage basic insulation architecture (one stage in HV side and one stage in external interface side) is used, because it can be regarded as double insulation, which is equivalent to reinforced insulation.

So, when using in-package hall-effect current sensors in solar system, firstly make sure that the key insulation specifications, such as clearance, creepage and VIOWM (Maximum basic or reinforced isolation working voltage) and so on can satisfy the application related safety standards and acquire the certificates. See SDAA213 to understand more about safety requirements and isolation needs for high-voltage applications.

Taking a 1500V solar inverter as an example, it requires at least 1061VRMS and 1500VDC VIOWM per VDE0884-17 or IEC 60747-17 for basic isolation working voltage. It requires at least 7.1mm clearance and 7.6mm creepage at the condition of OVC I, CTI-I, pollution degree 2 and 4000m working altitude, per IEC 62477-1:2022. The minimum clearance and creepage increase to 8.15mm for both if working altitude increase to 5000m.

Texas Instruments has a wide Hall-effect current sensors portfolio, such as TMCS112x, TMCS113x and TMCS114x that can satisfy the safety and isolation requirements and have related certificates available.

Typical Isolation Design of String Inverter Figure 6-1 Typical Isolation Design of String Inverter

Another important consideration to use in-package hall-effect current sensors in solar system is long lifetime reliability. Solar inverters usually require more than 25 years of quality guarantee, which means there are strict reliability requirements on device isolation performance. For TI's Hall sensor products, the separation between the input conductor and the Hall sensor die due to the TMCS1126 construction provides inherent galvanic isolation between package pins on the high-voltage input side, and package pins on the low-voltage output side. In addition, TI uses special insulation materials to form the insulator.