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The concept of IGBT driver isolation


The concept of IGBT driver isolation

What is quarantine?

Galvanic isolation: Charge cannot move from one circuit to another, and signals from both parties exchange information through other means.


The importance of IGBT driver isolation:

Ensure IGBT system and personal safety

Improving the performance of power electronic equipment in noisy environments

Safety isolation: Isolate potentially fatal voltage on the low-voltage ground side of the IGBT system control side

Level Shifting: Matching Signal Impedance to Common Mode Voltage Level

Noise Cancellation: Isolate noisy grounds from noise-sensitive circuits

Why does IGBT driver need isolation in motor control?

Circuit Problem 1: Voltage Transient

A fast, sudden, and often high-intensity voltage surge between two circuits


Circuit Problem 2: Common Mode Transient Voltage

How does motor control operation create common mode issues?

IGBT gate drive input control circuit and output control circuit share level difference

Reverse recovery characteristics of freewheeling diodes.


Circuit Problem Three: Ground Loop

Unexpected current flow caused by finite impedance between grounds connecting two conductors of different ground levels


Circuit Issue 4: Safe Isolation of Hazardous High Voltage at Different Voltage Levels

Level translation: circuit incompatibility between different voltage levels


Meet safety and regulatory standards

Insulation code requirements, including creepage distances, clearances and insulation distances

Test voltage (pulse, AC or DC) requirements


Ideal model for IGBT driver isolation:

Input/output signal paths exhibit low impedance

High impedance between input/output ground

Isolation effect:

Regardless of whether there is a common mode difference, the input signal can be directly transmitted to the output signal side

There is no current between the ground on the input side and the ground on the output side (reducing noise)


Isolation is a necessary part of many application systems, and system engineers need high-performance, advanced electronic components to make isolation simple to solve the challenges encountered.

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