Power Switch Driver Circuit Parasitic Switching Prevention
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Solution Overview
Problem
Existing power electronic device assemblies fail to prevent parasitic switching-on of power switches when the driver supply voltage is excessively low or not present, leading to potential damage to the power unit due to the inability of the Miller-clamp function to operate effectively.
Innovation Solution
Incorporating an additional wire connection device between the driver circuit and the power switch, which short-circuits the input of the power switch to a safety potential or negative supply voltage when the driver supply voltage is insufficient, ensuring discharge of parasitic charge current and preventing undesirable switching-on.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driver circuit is supplemented with additional protective circuitry to ensure operation at low voltage, then protection reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent merges the discharge switch and discharge capacitor into the existing driver-IC structure, combining them with the primary Miller-clamp circuitry. This integration allows the additional protective function to be added without significantly increasing overall device complexity or requiring separate discrete components.
Solution Approach 2:
The discharge capacitor serves multiple functions: it acts as a backup energy source for the Miller-clamp protection, provides a discharge path for parasitic charges during low-voltage conditions, and can be integrated with existing driver circuit components. This multi-functionality reduces the need for additional dedicated protective components.
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
This solution effectively prevents parasitic switching-on even at low or zero supply voltage, reducing the risk of damage to the power unit and allowing the use of existing driver circuits, thereby lowering costs and simplifying the supplementation of existing power units.
Implementation Method 1
the additional wire connection device is configured such that when a supply voltage for the driver circuit or, in some cases, for the short circuit, is not applied or is excessively low, the input of the power switch is short-circuited by the reference leg of the power switch or is coupled to a safety potential at which discharge is secured, whereby discharge of parasitic charge current generated on the input of the power switch is secured
Data Source
AI summary
Disclosed herein is a power electronic device assembly for preventing parasitic switching-on of a feeder circuit breaker. The assembly includes a logic circuit, a power switch with an input and a reference leg, and a driver circuit which drives the power switch. The driver circuit includes a drive unit and a short circuit having a safety function. When the input of the power switch is not operated, the power switch is short-circuited by the reference leg so that the potential of the input decreases below a switching-on threshold. An additional wire connection device is disposed between the driver circuit and the power switch and configured such that when no or excessively small amount of supply voltage is applied, the input of the power switch is short-circuited or is coupled to a safety potential at which discharge is secured, whereby discharge of parasitic charge current is secured.