Switched-Capacitor Feedback Circuit for Stable Reference Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic circuits with switched capacitor circuits face performance degradation due to temperature and process variations, leading to unstable reference voltages and signal delays, which affect the reliability and speed of operations such as analog-to-digital conversions.
Innovation Solution
A feedback circuit is introduced to stabilize the reference voltage and partially cancel the capacitance of the switched capacitor circuit, using differential operational amplifiers and feedback amplifiers to generate stabilized reference signals insensitive to temperature and process variations, thereby reducing signal delays and increasing bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switched capacitor circuits are used in analog-to-digital converters, then signal processing capability is improved, but reference voltage stability deteriorates due to temperature and process variations
Solution Approach 1:
The patent implements a feedback circuit that senses the reference voltage and adjusts it dynamically to compensate for temperature and process variations. The feedback mechanism monitors the actual reference voltage level and modifies the voltage output to maintain stability, directly addressing the reliability issue while preserving the high-speed signal processing capability of the switched capacitor circuit
Solution Approach 2:
The patent employs parameter-changing circuits that adjust circuit parameters (such as resistance or capacitance values) based on temperature and process conditions. By dynamically modifying these parameters, the system compensates for variations that would otherwise degrade reference voltage stability, allowing the switched capacitor circuit to maintain both performance and reliability under varying operating conditions
2Speed
If switched capacitor circuits operate at high speed, then bandwidth is improved, but signal delays increase due to capacitance effects
Solution Approach 1:
The patent introduces intermediary circuits (such as buffer stages or impedance matching networks) between the switched capacitor elements and the rest of the circuit. These intermediaries isolate the capacitive effects that cause signal delays, allowing the main switched capacitor circuit to operate at high bandwidth while the intermediary stages manage the timing and signal integrity, thereby reducing overall signal delays
3Device complexity
If conventional reference buffers are used, then circuit complexity is reduced, but performance degrades under temperature and process variations
Solution Approach 1:
The patent transitions from static reference buffers to dynamic reference voltage generation circuits that actively adapt to changing temperature and process conditions. The dynamic circuit continuously adjusts its operation based on real-time environmental parameters, maintaining performance stability without requiring excessively complex compensation networks, thus achieving a balance between complexity and reliability
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A switched-capacitor circuit comprising a differential operational amplifier (206) and a feedback circuit (204A, 204B) is described. In some embodiments, the feedback circuit (204A, 204B) may be configured to provide a reference voltage (Vr1, Vr2) that is insensitive to temperature and/or process variations. In some embodiments, the feedback circuit may be configured to mitigate the time delay associated with one or more capacitors (Cs1, Cs2) of the switched-capacitor circuit. The switched-capacitor circuit may be controlled by a pair of control signals. During a first phase, one or more capacitors (Cs1, Cs2) may be charged, or discharged, through an input signal (Vi+, Vi-). During a second phase, the electric charge of the one or more capacitors (Cs1, Cs2) may be retained.