Bandgap Reference Circuit With Collector Current Compensation
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Solution Overview
Problem
Existing bandgap reference voltage generation circuits face challenges in maintaining stable output voltage due to variations in process, voltage, and temperature, particularly when using transistors with low amplification factors, leading to increased collector current differences and degraded performance.
Innovation Solution
A bandgap reference voltage generation circuit that includes a current generator with transistors and resistors to generate PTAT current, an amplification part forming a negative feedback loop, and a compensation circuit to equalize collector currents, using a replica transistor to match base-emitter currents and compensate for collector current mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If short-channel MOS devices are used to enhance competitiveness, then productivity and device performance are improved, but the amplification factor of bipolar junction transistors decreases
Solution Approach 1:
The patent introduces a compensation circuit that changes the operating parameters of the transistor by generating a compensation current proportional to the base-emitter current. This compensation current adjusts the collector current to account for the reduced amplification factor, thereby maintaining reliable operation despite using short-channel MOS devices with lower beta values
2Device complexity
If transistors with low amplification factors are used, then device complexity is reduced, but the base-to-emitter current increases causing large collector current differences
Solution Approach 1:
The patent employs a feedback mechanism where the compensation circuit continuously monitors the base-emitter current and generates a compensating signal. This feedback loop adjusts the collector current in real-time to compensate for the increased base-emitter current, thereby maintaining precise current matching between transistors despite using devices with low amplification factors
3Ease of operation
If the base-to-emitter current increases, then the circuit can operate with simpler transistors, but the collector current difference degrades bandgap reference characteristics
Solution Approach 1:
The patent introduces a compensation current as an intermediary element that mediates between the increased base-emitter current and the required collector current stability. This compensation current acts as a buffer that absorbs the effects of high base-emitter current while maintaining the precise collector current matching needed for reliable bandgap reference operation
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 provides a stable reference voltage that is robust to process, voltage, and temperature variations, even with transistors having low amplification factors, ensuring consistent performance across varying conditions.
Implementation Method 1
generates a PTAT current proportional to absolute temperature using a base-emitter voltage difference between the first transistor and the second transistor
Implementation Method 2
an amplification part configured to form a negative feedback loop to the first transistor and the second transistor
Implementation Method 3
a compensation circuit configured to compensate for a difference in collector current between the first transistor and the second transistor
Data Source
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AI summary
The present invention relates to a bandgap reference voltage generation circuit capable of stably generating a bandgap reference voltage, and a semiconductor device having same. The present invention may comprise: a current generator which includes a first transistor, a first resistor connected to a collector end of the first transistor, a second transistor, a second resistor connected to a collector end of the second transistor, and a fourth resistor connected to emitter ends of the first transistor and the second transistor, and generates a PTAT current proportional to absolute temperature by using the second resistor connected to the second transistor and a base-emitter voltage difference between the first transistor and the second transistor; an amplification part for forming a negative feedback loop in the first transistor and the second transistor; a power supply for supplying power to the current generator via a third resistor; and a compensation circuit for compensating for a collector current difference between the first transistor and the second transistor.