Bandgap Reference Circuit with Split Power for Noise Isolation
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Solution Overview
Problem
Semiconductor devices face challenges in maintaining reliable reference voltages due to noise interference from circuits sharing the same substrate, particularly as chips become more integrated and miniaturized, leading to increased PVT variations and noise influence on bandgap reference circuits.
Innovation Solution
A bandgap reference circuit utilizing heterogeneous power (analog and digital power) is implemented, with a bipolar junction transistor (BJT) having separate power connections for its collector and base nodes, and a resistor connected to an emitter node, generating a reference voltage insensitive to PVT variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If circuits are highly integrated and miniaturized on the same substrate, then productivity and device functionality are improved, but noise interference on the bandgap reference circuit increases and reliability deteriorates
Solution Approach 1:
The patent divides the power supply into separate analog power and digital power domains. The bandgap reference circuit is supplied with analog power while digital circuits are supplied with digital power, segmenting the power distribution to prevent noise coupling between analog and digital sections while maintaining high integration.
Solution Approach 2:
The patent introduces separate power supply paths and power domains as intermediary structures between analog and digital circuits. These intermediary power distribution networks act as isolation barriers that prevent direct noise transmission while allowing both circuits to coexist on the same substrate.
2Device complexity
If the bandgap reference circuit shares the same substrate with other circuits, then device complexity is reduced, but noise from other circuits increases and measurement precision deteriorates
Solution Approach 1:
The patent applies different power supply qualities to different regions of the circuit. The bandgap reference circuit receives clean analog power with specialized noise filtering, while digital circuits receive digital power. This local differentiation of power quality allows high integration while maintaining reference voltage accuracy.
3Device complexity
If a single power supply is used for all circuits, then device complexity is reduced, but noise interference increases and reliability of the reference voltage deteriorates
Solution Approach 1:
The power supply is segmented into multiple independent domains: analog power for the bandgap reference circuit and digital power for digital circuits. This segmentation prevents noise from digital switching operations from contaminating the sensitive analog reference voltage, thereby improving reliability while maintaining manageable complexity through systematic power distribution.
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.