Voltage Reference Trimming for Stable Output at Low Quiescent Current
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Solution Overview
Problem
Precision voltage reference circuits face challenges in maintaining accurate and stable output voltage over a temperature range while minimizing quiescent current, especially in battery-powered or remote devices where power consumption is a concern.
Innovation Solution
A two-temperature trimming method is employed for voltage reference circuits, involving the adjustment of specific resistors in both the differential and scaling amplifier stages to equalize current flow and set the output voltage to a target value at multiple temperatures, reducing variability and quiescent current without requiring additional active components or pinouts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional voltage reference circuits are used to maintain accurate and stable output voltage over temperature range, then voltage stability is improved, but quiescent current consumption increases
Solution Approach 1:
The patent applies parameter changes by implementing a two-temperature trimming process that adjusts resistor values (RDEGEN, R1, R2, RPTAT, R1PTAT, R2PTAT) to optimize circuit performance. The trimming equalizes current flow through the differential and scaling amplifier stages at different temperatures, achieving voltage stability across temperature ranges while minimizing quiescent current consumption.
2Measurement precision
If additional active components are added to improve voltage reference accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing two-temperature trimming during the manufacturing process to pre-calibrate resistor values. This preliminary calibration ensures accurate voltage reference output across the operating temperature range without requiring additional active components or complex runtime adjustment mechanisms.
Solution Approach 2:
The patent applies self-service by designing the circuit to self-equalize current flow through the differential and scaling amplifier stages via the trimming process. The circuit automatically compensates for temperature-induced variations without requiring external intervention or additional control components during operation.
3Use of energy by moving object
If current flow through amplifier stages is not equalized, then power consumption is reduced, but output voltage accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting resistor values (RDEGEN, R1, R2, RPTAT, R1PTAT, R2PTAT) through a two-temperature trimming process. This trimming equalizes current flow through the differential and scaling amplifier stages at different temperatures, achieving voltage stability across temperature ranges while minimizing quiescent current consumption.
Data Source
AI summary
In an example method of trimming a voltage reference circuit, the method includes: setting the circuit to a first temperature; trimming a first resistor (RDEGEN) of a differential amplifier stage of the circuit; and trimming a first resistor (R1) of a scaling amplifier stage of the circuit. The trimming equalizes current flow through the differential amplifier stage and the scaling amplifier stage. The method includes: trimming a second resistor (R2) of the scaling amplifier stage to set an output voltage of the circuit to a target voltage at the first temperature; setting the circuit to a second temperature; and trimming a second resistor (RPTAT) of the differential amplifier stage, a third resistor (R1PTAT) of the scaling amplifier stage, and a fourth resistor (R2PTAT) of the scaling amplifier stage to set the output voltage of the circuit to the target voltage at the second temperature.