Power Semiconductor Control Circuit Parasitic ON Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power semiconductor circuits face issues with parasitic ON of switches due to induced voltages in low-impedance conductors and increased power-up losses, particularly when multiple branches are connected in parallel, leading to higher costs and complexity.
Innovation Solution
A control circuit design that uses impedance components to decouple the power supply of drivers from the control circuit, allowing for a common voltage source to power low-side switches while preventing unwanted current flow and reducing power-up losses by using impedance components with a magnitude greater than 0.3 times the gate resistance, and employing power drivers configured as emitter or source followers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common low voltage source is used to power drivers of low-side switches and parallel controllable power semiconductor switches, then device complexity is reduced, but parasitic ON of switches occurs due to induced voltages in parasitic inductances
Solution Approach 1:
The patent divides the common power supply into separate power supply circuits for each controllable power semiconductor switch. Each power supply circuit is connected to the emitter or source contact of its corresponding switch through a dedicated low-impedance conductor, preventing parasitic voltage induction from affecting other switches. This segmentation maintains reliability while managing complexity through modular organization.
Solution Approach 2:
The patent introduces separate power supply circuits as intermediary elements between the common low voltage source and individual switches. These intermediary circuits isolate each switch's driver from parasitic inductances in the load circuit, preventing unwanted voltage induction while still allowing coordinated control through the common power source.
2Speed
If low-impedance conductors are used to interconnect emitter and source contacts of low-side switches, then switching speed is improved, but power-up losses increase due to negative feedback from common inductance
Solution Approach 1:
The patent segments the power supply connections so that each driver receives power through its own dedicated low-impedance conductor from the emitter or source contact. This eliminates the common inductance path that causes negative feedback, thereby reducing power-up losses while maintaining fast switching speeds through the low-impedance connections.
3Reliability
If separate power supplies are used for each controllable power semiconductor switch, then reliability is improved by preventing parasitic ON, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple separate power supply circuits into a single common low voltage source that powers all drivers. However, each switch still receives power through its own dedicated connection path from the common source, maintaining the reliability benefits of separate power supply paths while reducing overall complexity through the shared power source.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces parasitic ON of switches and power-up losses, lowering costs and complexity by ensuring reliable signal transmission and minimizing current flow through the control circuit, thus enhancing the efficiency and reliability of power semiconductor assemblies.
Implementation Method 1
An impedance component (121, 221, 321; 421, 521, 621) is provided in each of the power supply lines (153, 253, 353; 453, 553, 653). The impedance component (121, 221, 321; 421, 521, 621) prevents currents from flowing via the power supply lines (153, 253, 353; 453, 553, 653) from the load circuit (101, 201, 301; 401, 501, 601) into the power supply of the driver (120, 220, 320; 420, 520, 620).
Data Source
AI summary
Disclosed is a control circuit for controlling a controllable power semiconductor switch, and to a power semiconductor module. The control circuit comprises at least two circuit sets, each having a power driver. The power driver of each of the circuit sets is provided with power via impedance components having an impedance other than zero.