Bandgap Detect/Modulate Circuit Fuse Tuning
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Solution Overview
Problem
Existing bandgap circuits in semiconductor chips face issues with output voltage deviation due to semiconductor process changes and are prone to damage from improper current control during fuse activation, leading to low voltage output and potential loss of function.
Innovation Solution
A detect/modulate circuit using transistor switches controlled by a logic controller to fine-tune the main resistor's absolute value, with a detect circuit monitoring fuse status to prevent direct current flow to the bandgap, thus avoiding damage and ensuring stable voltage output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fuses are not fused before chip processing to enable both positive and negative fine tunings, then fine tuning capability is improved, but voltage output becomes too low
Solution Approach 1:
The patent introduces a detect circuit as an intermediary between the fuse and the bandgap circuit. This detect circuit monitors fuse status and provides feedback to a logic controller, which then controls transistor switches to adjust the resistor network. This intermediary system allows the fuse to be used for fine-tuning without directly exposing the bandgap to uncontrolled current, thereby maintaining both fine-tuning capability and proper voltage output levels.
2Adaptability or versatility
If current is controlled improperly during fuse operation, then fine tuning is achieved, but the bandgap is damaged and loses function
Solution Approach 1:
The patent implements a feedback mechanism where the detect circuit continuously monitors the fuse status and communicates this information to the logic controller. The logic controller uses this feedback to intelligently control the transistor switches, ensuring that current flows are properly managed during the fine-tuning process. This feedback system prevents improper current control that could damage the bandgap while still enabling effective fine-tuning of the voltage output.
3Stability of the object's composition
If transistor switches are used to fine-tune the main resistor, then voltage output stability is improved, but device complexity increases
Solution Approach 1:
The detect circuit serves multiple functions: it detects fuse status, generates feedback signals, and works with the logic controller to manage transistor switch operation. By making the detect circuit multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity while still achieving improved voltage output stability through the transistor switch network.
Data Source
AI summary
A detect/modulate circuit comprises a plurality of modulate resistors connected to a main resistor of a bandgap in series, and each module resistor is connected to a transistor switch in parallel, and each transistor switch is connected to a logic controller, and the logic controller is connected in sequence to a plurality of detect circuits and fuses corresponding to the quantity of the transistor switches. When the detect circuit receives a low-to-high power-on reset signal to detect whether or not the fuse is fused, the detect circuit will issue a voltage level signal “0” for the fuse being not fused or a voltage level signal “1” for the fuse being fused to the logic controller. The logic controller converts the received voltage level signal according to a logic conversion table to control the electric connection of the corresponding transistor switch, so as to fine turn the main resistance of the bandgap.