Low-Voltage Bandgap Reference Circuit for PVT-Stable Output
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Solution Overview
Problem
As semiconductor technology advances, transistor gate lengths and maximum supply voltage have decreased, affecting the stability of bandgap reference circuits due to variations in Process, Voltage, and Temperature (PVT), leading to challenges in maintaining a steady reference voltage.
Innovation Solution
A bandgap reference circuit design incorporating separate current branches for proportional to absolute temperature (PTAT) and complementary to absolute temperature (CTAT) voltages, with a resistive output providing a weighted sum, ensuring robustness across PVT variations and sufficient voltage headroom for low supply voltage systems, utilizing bipolar junction transistors and metal oxide semiconductor field effect transistors (MOSFETs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistor gate length is reduced to advance semiconductor technology, then device scaling and integration are improved, but maximum supply voltage tolerance decreases and breakdown risk increases
Solution Approach 1:
The patent changes the operating voltage parameters by introducing a low-voltage bandgap reference circuit that operates at supply voltages below 1.2V, with specific embodiments operating at 0.9V and 0.6V. This parameter change allows the circuit to adapt to reduced supply voltage conditions while maintaining reference voltage stability, resolving the contradiction between device scaling and voltage tolerance.
2Loss of energy
If supply voltage is reduced for low voltage systems, then power consumption is decreased, but voltage headroom for stable bandgap operation becomes insufficient
Solution Approach 1:
The patent segments the bandgap reference circuit into multiple functional blocks: a first circuit block generating a first current, a second circuit block generating a second current, and a third circuit block generating the reference voltage from these currents. This segmentation allows each block to be optimized for low-voltage operation while maintaining overall reference voltage stability, enabling operation at supply voltages as low as 0.6V without sacrificing stability.
Solution Approach 2:
The patent changes the operating voltage parameters by designing the circuit to operate at supply voltages below 1.2V, with specific embodiments operating at 0.9V and 0.6V. The circuit uses specialized transistor configurations and current mirror designs that maintain proper voltage headroom at these reduced supply voltages, allowing low power consumption while preserving reference voltage stability.
3Device complexity
If conventional bandgap reference circuits are used in low voltage systems, then design simplicity is maintained, but reference voltage stability deteriorates due to insufficient voltage headroom
Solution Approach 1:
The patent segments the bandgap reference circuit into distinct functional blocks that can be independently optimized. The first circuit block generates a first current, the second circuit block generates a second current, and the third circuit block combines these to produce the reference voltage. This modular segmentation maintains design clarity while enabling stable operation at low supply voltages where conventional unified designs would fail.
Solution Approach 2:
The patent changes the operating voltage parameters by designing the circuit to operate at supply voltages below 1.2V, with specific embodiments operating at 0.9V and 0.6V. The circuit uses specialized transistor configurations and current mirror designs that maintain proper voltage headroom at these reduced supply voltages, allowing low power consumption while preserving reference voltage stability.
Data Source
AI summary
In some aspects of the present disclosure, a bandgap reference circuit includes a first current mirror and a first resistor coupled to the first current mirror to provide a proportional to absolute temperature (PTAT) voltage. The circuit includes a second current mirror and a bipolar junction transistor (BJT) device coupled to the second current mirror to provide a complementary to the absolute temperature (CTAT) voltage. The circuit includes an output node to provide a bandgap voltage that is a weighted sum of the PTAT voltage and the CTAT voltage. The circuit includes a second resistor coupled between the output node and a first node, wherein the first node is coupled between the first resistor and the first current mirror. The circuit includes a third resistor coupled between the output node and a second node, wherein the second node is coupled between the BJT device and the second current mirror.