Output Stage Auxiliary Electrode Width Variation for Current Density
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Solution Overview
Problem
Operational amplifiers face challenges in maintaining high driving capacity under high current conditions, as existing protection circuits like over current protect (OCP) and over temperature protect (OTP) often fail to optimize performance.
Innovation Solution
The structure of the output stage includes a configuration of auxiliary electrodes and switching units, where the width of each auxiliary electrode varies inversely with its distance from the main electrodes, and PMOS and NMOS-type transistors are used to enhance current flow directionally from one electrode to another, optimizing driving capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the width of the output stage is enlarged to advance driving capacity, then the high current condition operation is improved, but the current density distribution becomes uneven causing hot spots and reduced reliability
Solution Approach 1:
The patent applies local quality by making the auxiliary electrodes have different widths at different positions. Specifically, the auxiliary electrodes have a larger width near the input electrode and a smaller width near the output electrode, creating non-uniform current density distribution that compensates for the natural current concentration at the center, thereby preventing hot spots while maintaining high driving capacity
Solution Approach 2:
The patent changes the geometric parameter (width) of the auxiliary electrodes to optimize current distribution. By varying the width of auxiliary electrodes along their length, the current density is redistributed to achieve more uniform heating across the output stage, resolving the contradiction between high power capability and hot spot resistance
2Reliability
If protection circuits (OCP and OTP) are added to limit current, then device safety is improved, but the driving capacity under high current conditions deteriorates
Solution Approach 1:
The patent implements preliminary action by pre-distributing current through auxiliary electrodes with optimized width profiles before the current reaches conditions that would trigger protection circuits. This preliminary current distribution prevents hot spot formation and excessive power dissipation, allowing the device to operate at higher currents without activating OCP or OTP, thereby maintaining driving capacity while ensuring safety
Data Source
AI summary
A structure of an output stage, and the structure includes a first electrode, a second electrode, a third electrode, a plurality of first auxiliary electrodes, a plurality of second auxiliary electrodes, a plurality of third auxiliary electrodes, a plurality of fourth auxiliary electrodes, a first switching unit, and a second switching unit. Wherein, a plurality of first currents flow through the turned-on first switching unit, and a first flowing direction of the first currents in the turned-on first switching unit is from the first electrode to the second electrode. A plurality of second currents flow through the turned-on second switching unit, and a second flowing direction of the second currents in the turned-on second switching unit is from the second electrode to the third electrode.