Temperature-Switched Bandgap Reference Circuit for Stable Voltage
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Solution Overview
Problem
Existing bandgap reference circuits experience significant fluctuations in reference voltage due to temperature, power supply, and loading changes, occupying substantial area on integrated circuits and requiring long start-up times.
Innovation Solution
A bandgap reference system comprising a first bandgap reference circuit, a low dropout regulator, a temperature circuit, and a second bandgap reference circuit, where the second bandgap reference circuit configures impedance elements based on temperature signals to provide a more stable reference voltage, with the low dropout regulator and temperature circuit aiding in voltage regulation and temperature sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing bandgap reference circuits are used to generate reference voltages, then reference voltage can be provided for various temperatures and power supplies, but the reference voltage exhibits significant fluctuations due to temperature, power supply, and loading changes
Solution Approach 1:
The patent implements a dynamic impedance configuration system where the second bandgap reference circuit adjusts its impedance elements based on temperature signals. The system includes a temperature circuit that generates temperature-dependent signals to control switches, which in turn reconfigure the impedance elements (resistors and capacitors) in real-time. This dynamic adaptation allows the circuit to maintain stable reference voltage output despite temperature variations, power supply changes, and loading conditions, directly resolving the stability issue described in the contradiction.
2Reliability
If existing bandgap reference circuits are used, then reference voltage can be generated, but the circuits occupy a substantial amount of area on an integrated circuit die
Solution Approach 1:
The patent divides the bandgap reference system into two distinct circuits: a first bandgap reference circuit that provides a basic reference voltage, and a second bandgap reference circuit that fine-tunes the output by configuring impedance elements based on temperature signals. This segmentation allows each circuit to be optimized for its specific function, reducing the overall area requirement compared to a single monolithic bandgap reference circuit that would need to handle all functions simultaneously.
Solution Approach 2:
The second bandgap reference circuit serves multiple functions: it receives the reference voltage from the first circuit, processes temperature signals, dynamically configures impedance elements, and outputs a compensated reference voltage. This multi-functionality consolidates what would otherwise require separate dedicated circuits, thereby reducing the total die area while maintaining reference voltage generation capability and temperature compensation.
3Reliability
If existing bandgap reference circuits are used, then reference voltage can be provided, but the circuits take a relatively long time to start-up
Solution Approach 1:
The first bandgap reference circuit operates continuously to provide a preliminary reference voltage output before the second bandgap reference circuit is fully activated. This preliminary reference voltage allows the system to begin functioning immediately upon power-up, while the second circuit gradually configures its impedance elements based on temperature signals. This staged activation reduces the overall start-up time compared to waiting for the entire system to initialize simultaneously.
Solution Approach 2:
The impedance configuration in the second bandgap reference circuit occurs periodically based on temperature signal thresholds. Rather than continuously adjusting all parameters from scratch during start-up, the system periodically reconfigures impedance elements as temperature conditions change, allowing for faster initialization and reducing the time required to achieve stable reference voltage output.
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 system achieves a significantly reduced reference voltage variation over temperature ranges, occupying less area and enabling quicker start-up times, lower current consumption, and improved noise and power supply rejection ratios.
Implementation Method 1
the temperature circuit includes a voltage generation circuit configured to generate a Proportional-to-Absolute-Temperature (PTAT) voltage
Data Source
AI summary
Circuits, systems, and methods to switch modes based on temperature and to provide reference voltages are discussed herein. For example, a bandgap reference circuit may include one or more impedance elements and one or more switches coupled to the one or more impedance elements. The one or more switches may be controllable based on a temperature signal. The bandgap reference circuit may be configured to provide a bandgap reference voltage that is associated with less than a particular amount of voltage variation.