Merged Reference Circuit for Low-Power Stable Voltage and Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage and current reference circuits consume high power and are sensitive to parameter variations such as temperature and supply voltage, making them inefficient for use in low-power devices like IoT devices.
Innovation Solution
A compact reference circuit using a dual-functional operational amplifier with a current mirror and pMOS transistors to generate both voltage and current references, reducing the need for separate voltage reference circuits and minimizing power consumption, while using a current buffer and compensation capacitor to maintain stability across temperature and supply voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage reference circuit is combined with an operational amplifier and output part to implement a current reference circuit, then the reference voltage and current can be provided with regulation capability, but the power consumption becomes relatively large
Solution Approach 1:
The patent combines the voltage reference circuit and current reference circuit into a single integrated structure where the operational amplifier serves dual purposes. The first and second transistors with the current mirror form both the voltage reference generation and the current reference regulation, eliminating the need for separate dedicated circuits and reducing overall power consumption while maintaining reference stability.
Solution Approach 2:
The operational amplifier is designed to perform multiple functions: it regulates the reference voltage generated by the transistor pair and simultaneously controls the current reference output. The current mirror with unity gain forces the same drain current through both transistors, enabling the circuit to provide both voltage and current references with a single amplification stage, thereby reducing power consumption.
2Reliability
If separate voltage reference circuit and current reference circuit are used, then the reference functions are reliable, but the circuit area and complexity increase
Solution Approach 1:
The patent merges the voltage reference circuit and current reference circuit into one unified structure. The operational amplifier with its feedback network simultaneously performs voltage regulation and current control functions. The first and second transistors with the current mirror generate the reference voltage while the same transistor pair, controlled by the operational amplifier, provides the current reference, thereby halving the circuit complexity.
3Stability of the object's composition
If the reference circuit is always-on to provide continuous reference, then the reference stability is maintained, but the power consumption during sleep mode increases device power usage
Solution Approach 1:
The patent enables the reference circuit to operate periodically rather than continuously. The operational amplifier and transistor network can be activated only when reference values are needed, allowing IoT devices to turn off the reference circuit during extended sleep periods. This periodic operation maintains reference stability when needed while dramatically reducing average power consumption during sleep mode.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A reference circuit (100; 200; 300) for providing voltage reference and current reference comprises: operational amplifier (110; 210; 310) comprising first transistor (112; 212; 312), second transistor (114; 214; 314) and current mirror (120; 220; 320) being configured to force a same drain current through first (112; 212; 312) and second transistor (114; 214; 314), wherein first (112; 212; 312) and second transistor (114; 214; 314) control voltage reference at first node (130; 230; 330) of reference circuit (100; 200; 300); and reference output (140; 240; 340) comprising reference resistor (142; 246, 248; 346, 348) connected between ground and first node (130; 230; 330) and reference transistor (144; 244; 345a, 345b), whereby reference circuit (100; 200; 300) is configured to provide voltage reference at first node (130; 230; 330) and current reference through reference resistor (142; 246, 248; 346, 348) and reference transistor (144; 244; 345a, 345b).