Current-Mode Reference Generator With Temperature Compensation
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Solution Overview
Problem
Conventional reference voltage generators are affected by temperature changes and power supply variations, requiring additional components like operational amplifiers and feedback circuits that increase power consumption, chip area, and reduce operating bandwidth.
Innovation Solution
A reference current/voltage generator incorporating a current mirror unit and a current-mode temperature compensation unit, which includes a BJT-based bandgap circuit and impedance circuits to generate currents with positive and negative temperature coefficients, resulting in a zero-temperature-coefficient output current and voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback circuits with comparators and switches are used to suppress temperature and power supply variations, then output reference voltage stability is improved, but operating bandwidth and speed decrease while chip area and power consumption increase
Solution Approach 1:
The patent extracts and eliminates the feedback circuit components (comparators, switches) from the reference voltage generator architecture. Instead of using active feedback control, the invention uses a simplified structure with current mirrors and temperature compensation circuits that inherently provide stable reference voltage without requiring additional control components, thereby reducing chip area while maintaining reliability
Solution Approach 2:
The patent replaces the mechanical/electronic feedback control system with an electrical current-based compensation mechanism. By using current mirrors and temperature compensation circuits that generate compensating currents, the system achieves voltage stability through electrical parameter matching rather than active feedback control, reducing device complexity
2Adaptability or versatility
If operational amplifier and voltage divider resistors are used to generate higher reference voltage from bandgap voltage, then reference voltage range is improved, but power consumption and chip area increase
Solution Approach 1:
The patent makes the current mirror unit multi-functional by configuring it to directly provide multiple current outputs (first current, first sum current, second sum current) that can be used for different voltage generation purposes. This eliminates the need for separate operational amplifiers and voltage dividers, reducing power consumption while maintaining voltage range adaptability through current scaling
Solution Approach 2:
The patent merges the functions of voltage amplification and temperature compensation into a single integrated current-mode circuit structure. The current mirror unit and temperature compensation unit work together to directly generate the required reference voltages without needing separate operational amplifier stages, thereby reducing overall power consumption
3Power
If operational amplifier is used to amplify bandgap reference voltage, then reference voltage level is improved, but power consumption and chip area increase
Solution Approach 1:
The patent replaces the operational amplifier-based voltage amplification mechanism with a current-mode amplification approach using current mirrors. The current mirror unit amplifies the reference current directly through current copying and scaling, eliminating the need for high-power operational amplifiers while achieving the required voltage level through the relationship V=IR
Solution Approach 2:
The patent changes the operating parameter from voltage-mode to current-mode throughout the reference generation circuitry. By using current mirrors and temperature compensation circuits that operate in current mode, the system achieves voltage level scaling through current multiplication followed by voltage conversion, which consumes less power than traditional voltage-mode operational amplifier approaches
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a reference current/voltage that is independent of temperature changes without the need for feedback circuits or additional amplifiers, reducing power consumption and maintaining high operating bandwidth.
Implementation Method 1
the first circuit generates the second current, the first impedance circuit generates the third current, wherein the second current is proportional to absolute temperature (PTAT)
Implementation Method 2
the two terminals of the first circuit and the second circuit electrically connected to the second terminal and the third terminal of the current mirror unit are biased by a first voltage and a second voltage, respectively. When the first voltage is equal to the second voltage, the first circuit generates the second current, the first impedance circuit generates the third current, wherein the second current is proportional to absolute temperature (PTAT), and the third current is complementary to absolute temperature (CTAT)
Data Source
AI summary
A reference current/voltage generator includes a current mirror unit and a current-mode temperature compensation unit. The current mirror unit generates a first current, a first sum current and a second sum current flowing through first to third terminals thereof, and the first current, the first sum current and the second sum current are in a multiple relationship. The current-mode temperature compensation unit is electrically connected to the second and third terminals of the current mirror unit, and when a voltage on the second terminal is equal to a voltage on the third terminal, the first sum current is a sum of a current proportional to absolute temperature (PTAT) and a current complementary to absolute temperature (CTAT). The first terminal of the current mirror unit is an output terminal of the reference current/voltage generator and configured to output the first current as a reference current.