Bandgap Reference Voltage Adjustment via Transistor Switches
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Solution Overview
Problem
Conventional reference voltage generating circuits in semiconductor chips face issues with voltage deviation due to varying semiconductor process conditions, leading to low output voltage and potential damage from inappropriate current control, and require fuses to be blown out before chip processing, which complicates precise '0' or '1' signal setup.
Innovation Solution
A logic controller is used to control transistor switches to fine-adjust the main resistor of a bandgap circuit, and a detection circuit compares resistance values to determine fuse status, allowing for accurate logic controller adjustments before manufacturing, thereby preventing low output voltage and avoiding fuse damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuses are blown out to fine adjust the main resistor, then the reference voltage deviation can be corrected, but the output voltage is lowered and the chips must be processed before packaged
Solution Approach 1:
The patent changes the adjustment mechanism from fuse blowing (binary on/off) to transistor switch control (continuous adjustment). The transistor switches controlled by logic controller allow precise adjustment of the main resistor value by selecting different connection points, enabling fine-tuning of reference voltage without permanently altering circuit parameters through fuse blowing.
Solution Approach 2:
The patent introduces dynamic control elements (transistor switches and logic controller) that allow the circuit to be adjusted after packaging. The transistor switches can be dynamically controlled to connect or disconnect adjusting resistors based on detected reference voltage values, enabling post-packaging adjustment without requiring pre-packaging processing.
2Reliability
If current is controlled inappropriately to blow out fuses, then the fuse status can be detected, but the reference voltage generating circuit may get damaged
Solution Approach 1:
The patent introduces an intermediary detection circuit that indirectly determines fuse status by measuring voltage drops across resistors rather than directly detecting fuse blowing. The logic controller analyzes these voltage drops to infer the connection status of adjusting resistors, avoiding the need to apply high currents that could damage the reference voltage generating circuit.
Solution Approach 2:
The patent replaces the mechanical fuse blowing method with an electronic control system using transistor switches. Instead of using high current to physically blow fuses, the system uses logic controller signals to electronically switch transistor states, which then control the connection of adjusting resistors. This substitution eliminates the harmful high current effect while achieving the same adjustment function.
3Measurement precision
If fuses must be blown out before chip processing, then precise '0' or '1' signal can be obtained, but the process complexity increases
Solution Approach 1:
The patent performs preliminary detection of reference voltage during normal operation and uses this information to control transistor switches accordingly. The logic controller detects the actual reference voltage value and automatically adjusts the transistor switch states to achieve the desired voltage level, eliminating the need for pre-processing fuse blowing operations.
Solution Approach 2:
The system uses its own reference voltage output as the basis for self-adjustment. The logic controller monitors the reference voltage generated by the circuit itself and automatically controls the transistor switches to adjust the main resistor value, enabling the circuit to self-correct without external intervention or complex pre-processing steps.
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 enables precise fine-adjustment of the bandgap circuit's output voltage without lowering it prematurely, prevents damage from excessive current, and simplifies material preparation by allowing accurate 'on' or 'off' signal control without blowing fuses, ensuring stable voltage generation and efficient chip processing.
Implementation Method 1
a logic controller 23 is used to control a plurality of transistor switches 22
Implementation Method 2
a detection circuit 24 compares resistance values of a resistor and a fuse within the detection circuit 24
Data Source
AI summary
A programmable detection adjuster is disclosed. The programmable detection adjuster comprises a bandgap and an adjusting circuit. The bandgap comprises a power input terminal, a voltage output terminal, a main resistance and a plurality of resistors. The adjusting circuit comprises a plurality of adjusting resistors, a plurality of transistor switches, a logic controller and detection circuits; said adjusting resistors connected to the main resistance of the bandgap in series. The adjusting resistors are respectively connected to the transistor switch in parallel. The transistor switches are connected to the logic controller. The logic controller is respectively connected to the detection circuits. The detection circuit detects the corresponding resistances in the detection circuit and outputs a voltage level to the logic controller to enable the logic controller to control a conduction of the transistor switches according to a logic conversion table.