The Importance of Isolation for High Voltage Electrical Systems

High voltage signal electrical isolation application scenarios: In industrial environments, when two devices are at different potentials, especially when there are high-power devices operating near the target device, the ground potential between the devices can often differ by several tens of volts. In such cases, directly connecting the two devices can generate significant ground loop currents. These ground loop currents can often exceed the signal current, causing communication failures or even burning out the circuits. In such cases, electrical isolation of the communication lines is necessary to cut off the aforementioned ground loop currents.

In motor control applications, the system needs to control the operation of a high voltage, high power motor, while operators need to interact with the motor control system through a human-machine interface. If the control system is not reliably isolated from the high voltage power circuit, high voltage can enter the control system along the control signal lines, posing a risk of electric shock to operators and endangering their safety.

If our system needs to acquire a small signal from external devices, electromagnetic interference in the environment can lead to significant amounts of electromagnetic noise being induced on the signal line. This interference can sometimes be much greater than the signal we need to acquire. If the interference is not appropriately isolated, it can often drown out useful signals.

(Image Source: Texas Instruments)

(Image Source: Texas Instruments)

Functional Block Diagram

SOIC (DWV) Package 5.85mm x 11.5mm

(Image Source: Texas Instruments)

• By integrating a wide input range low-dropout regulator, a window comparator, and a precision voltage reference, the solution size is reduced by 50%.
• In the worst-case scenario, the transition threshold accuracy is less than 3%, helping engineers reduce design margins and support smaller passive components.
• Response time of less than 400ns provides ultra-fast overcurrent and overvoltage detection, better protecting the system.
• Adjustable transition thresholds via a single external resistor facilitate reuse across different designs.

(Image Source: Texas Instruments)

Related Technical Documents and Resources

• TI AMC23C12 Product Page

• AMC23C12 Datasheet

• White Paper – Leveraging Reliable and Cost-Effective Isolation Technologies to Address High Voltage Design Challenges

• White Paper – Using Isolated Comparators for Fault Detection in Motor Drivers

• Circuit Design – Isolated Overcurrent Protection Circuit

• TI Isolation Product Overview

• Digi-Key TI Isolation Product Center