B-TRAN Base Injection Control for Low-Loss Fast Turn-Off
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Solution Overview
Problem
Bi-directional double-base bipolar junction transistors (B-TRANs) face challenges in efficiently managing forward voltage drops and switching times, leading to increased conduction losses and switching losses due to varying conduction modes and turn-off times.
Innovation Solution
A method and system for operating B-TRANs that involve injecting charge carriers at different rates into the upper base to control forward voltage drops and conductivity, with a first rate for low voltage during most of the conduction period and a second rate to increase voltage near the end, facilitating a quicker transition to a non-conductive state, thereby optimizing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If charge carriers are injected at a high rate into the upper base to maintain low forward voltage drop during conduction, then conduction losses are reduced, but switching time increases and switching losses increase
Solution Approach 1:
The patent applies periodic action by varying the charge carrier injection rate into the upper base according to different phases of the conduction period. During most of the conduction period, charge carriers are injected at a first rate to maintain low forward voltage drop and reduce conduction losses. Within a predetermined period before the end of the conduction period, the injection rate is reduced to a second rate (lower than the first rate) to decrease stored charge and facilitate faster turn-off, thereby reducing switching time and switching losses. This time-varying injection strategy resolves the contradiction between maintaining low conduction losses and achieving fast switching.
2Productivity
If charge carriers are injected at a high rate to maintain transistor conduction, then current flow is sustained, but turn-off time increases
Solution Approach 1:
The patent applies preliminary action by reducing the charge carrier injection rate into the upper base within a predetermined period before the end of the conduction period. This preliminary reduction in injection rate decreases the stored charge in the base before the turn-off event, preparing the transistor for faster switching. By anticipating the upcoming turn-off and adjusting the injection rate in advance, the patent reduces the time required to remove stored charge and achieve the non-conductive state, thereby reducing turn-off time while maintaining sustained current flow during the main conduction period.
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 approach reduces switching losses and improves overall efficiency by managing voltage drops and conductivity, enhancing the B-TRAN's operational performance by minimizing conduction and switching losses.
Implementation Method 1
injecting charge carriers at a first rate into an upper base of the transistor, the injecting at the first rate results in current flow through the transistor
Implementation Method 2
A bi-directional double-base bipolar junction transistor (hereafter B-TRAN) is junction transistor constructed with a base and collector-emitter on a first side of the bulk region
Data Source
AI summary
Operating a bi-directional double-base bipolar junction transistor (B-TRAN). One example is a method comprising: injecting charge carriers at a first rate into an upper base of the transistor, the injecting at the first rate results in current flow through the transistor from an upper collector-emitter to a lower collector-emitter, and the current flow results in first voltage drop measured across the upper collector-emitter and the lower collector-emitter; and then, within a predetermined period of time before the end of a first conduction period of the transistor, injecting charge carriers into the upper base at a second rate lower than the first rate, the injecting at the second rate results in second voltage drop measured across the upper collector-emitter and the lower collector-emitter, the second voltage drop higher than the first voltage drop; and then making the transistor non-conductive at the end of the conduction period.