Bootstrap Circuit High Voltage Cut-Off for Leakage Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power semiconductor devices with bootstrap circuits are prone to failure due to high voltages, causing current leakage to the semiconductor substrate and requiring additional module size for stability in variable reference voltage environments.
Innovation Solution
A power semiconductor device incorporating a bootstrap driving circuit with a charge enable unit and high voltage cut-off unit, including a PNP transistor and n-channel JFET, respectively, to manage voltage levels and prevent current leakage, while maintaining operational stability across varying voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bootstrap circuit is connected externally to an HVIC, then the high voltage unit can operate in a variable reference voltage environment, but the module size increases and the bootstrap circuit is vulnerable to high voltage damage
Solution Approach 1:
The patent integrates the bootstrap circuit functions directly into the HVIC chip by incorporating a charge enable unit and high voltage cut-off unit within the semiconductor device structure. This merging eliminates the need for external bootstrap circuit connections, reducing module size while maintaining the ability to operate the high voltage unit in variable reference voltage environments.
Solution Approach 2:
The patent introduces a high voltage cut-off unit as an intermediary component between the charge enable unit and the high voltage unit. This cut-off unit prevents high voltage from reaching sensitive components during high voltage operation, protecting the bootstrap circuit from damage while enabling proper bootstrap functionality.
2Power
If the bootstrap driving circuit is exposed to high voltage, then it can control the high voltage unit, but the circuit breaks down and current leaks to the semiconductor substrate
Solution Approach 1:
The patent divides the bootstrap driving circuit into two separate functional units: a charge enable unit for charging the bootstrap capacitor and a high voltage cut-off unit for preventing high voltage exposure. This segmentation allows each unit to operate within its safe voltage range while collectively enabling high voltage control capability.
Solution Approach 2:
The high voltage cut-off unit serves as a protective intermediary that isolates the charge enable unit from high voltage conditions. By introducing this intermediate protective layer, the circuit maintains integrity during high voltage operation while still enabling the high voltage unit to be controlled.
3Device complexity
If elements in the bootstrap driving circuit form a parasite transistor, then current flows to the semiconductor substrate, but the circuit structure is already established
Solution Approach 1:
The high voltage cut-off unit acts as an intermediary barrier that prevents current leakage to the semiconductor substrate by blocking the formation of parasitic transistor conduction paths. This intermediate protective structure eliminates harmful current flow while maintaining the established circuit structure.
Solution Approach 2:
The patent addresses the parasitic transistor issue by using the high voltage cut-off unit to convert the potentially harmful current leakage path into a controlled isolation mechanism. The cut-off unit transforms what would be a harmful effect into a beneficial protective function.
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 ensures the bootstrap driving circuit is not broken by high voltages and blocks current flow to the substrate, enhancing the stability and reliability of the power semiconductor device in variable reference voltage environments.
Implementation Method 1
The bootstrap circuit also includes a diode. The diode may open the bootstrap circuit when a PWM signal is at logic high and may supply a current to a capacitor by providing a current path when the PWM signal is at logic low.
Implementation Method 2
The bootstrap circuit includes a capacitor connected in parallel to the high voltage unit at a driving power source terminal of the high voltage unit.
Implementation Method 3
using a PNP transistor and n-channel JFET to manage voltage levels, ensuring the bootstrap driving circuit remains operational under high voltage conditions
Data Source
AI summary
Disclosed is a power semiconductor device including a bootstrap circuit. The power semiconductor device includes a high voltage unit that provides a high voltage control signal so that a high voltage is output; a low voltage unit that provides a low voltage control signal so that a ground voltage is output, and is spaced apart from the high voltage unit; a charge enable unit that is electrically connected to the low voltage unit and charges a bootstrap capacitor for supplying power to the high voltage unit when the high voltage is output, when the ground voltage is output; and a high voltage cut-off unit that cuts off the high voltage when the high voltage is output so that the high voltage is not applied to the charge enable unit, and includes a first terminal electrically connected to the charge enable unit and a second terminal electrically connected to the high voltage unit.