Bandgap Reference Circuit Using Split Power Domains Against Substrate Noise
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Solution Overview
Problem
Highly integrated and miniaturized semiconductor chips face increased noise interference from shared substrates, affecting the reliability of bandgap reference circuits, which generate reference voltages insensitive to process-voltage-temperature (PVT) variations.
Innovation Solution
A bandgap reference circuit is designed to operate using heterogeneous power (analog and digital power) with a bipolar junction transistor (BJT) configuration, where the collector node is connected to the semiconductor substrate and shares power with a digital circuit, while the base node is supplied with a different power, reducing noise influence and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bandgap reference circuit shares the same substrate with digital circuits for high integration, then device integration is improved, but noise interference increases
Solution Approach 1:
The patent segments the power supply into heterogeneous power domains by providing different power voltages to the bandgap reference circuit and digital circuits. This segmentation creates separate power domains that reduce noise coupling while maintaining physical integration on the same substrate, thus resolving the contradiction between high integration and noise interference.
Solution Approach 2:
The patent introduces an intermediary power supply structure that acts as a mediator between the digital circuits and the bandgap reference circuit. By using separate power voltage sources and power domains, the intermediary power structure isolates noise from digital circuits while allowing both circuits to coexist on the same substrate, thereby reducing noise interference without sacrificing integration.
2Device complexity
If the bandgap reference circuit uses a single power supply for simplicity, then device complexity is reduced, but reliability of reference voltage deteriorates
Solution Approach 1:
The patent applies local quality by providing different power voltages specifically to the bandgap reference circuit nodes that are most susceptible to noise. Rather than complicating the entire power supply system, the heterogeneous power is applied locally to critical nodes, improving reference voltage reliability without excessive complexity.
Solution Approach 2:
The patent changes the power supply parameter from a single unified voltage to multiple heterogeneous voltages. By adjusting and optimizing each power voltage independently, the reference voltage reliability is improved through parameter optimization, while the complexity is managed through systematic power domain design.
Data Source
AI summary
Disclosed is a bandgap reference circuit, which includes a first current generator that generates a first current proportional to a temperature, a second current generator that outputs a second current obtained by mirroring the first current to a first node at which a reference voltage is formed, a first resistor that is connected with the first node and is supplied with the second current, and a first bipolar junction transistor (BJT) that includes an emitter node connected with the first resistor, a base node supplied with a first power, and a collector node supplied with a second power different from the first power.