Switched-Capacitor Differential Amplifier for Flexible Output Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analog signal processing circuit blocks require reconfiguration of switched capacitor networks to switch between fully differential and single-ended output modes, affecting frequency and time response characteristics, which is inconvenient and inefficient.
Innovation Solution
An analog signal processing circuit block with a differential amplifier and switched capacitor networks that can operate in either fully differential or single-ended output modes without reconfiguring the switched capacitor networks, using digital control signals to select the mode and disabling or disconnecting specific components as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switched capacitor networks are reconfigured to switch between fully differential and single-ended output modes, then output mode versatility is improved, but frequency and time response characteristics are affected (worsened)
Solution Approach 1:
The circuit is segmented into independent functional blocks: switched capacitor networks for frequency/time response control and differential amplifier output stages for output mode control. This segmentation allows the output stage to be reconfigured without affecting the switched capacitor networks, thus maintaining frequency and time response characteristics while enabling output mode versatility.
Solution Approach 2:
The output mode selection functionality is extracted from the switched capacitor networks and placed in the differential amplifier output stage. By taking out the output mode control from the frequency-response-determining switched capacitor networks, the patent eliminates the interference between output mode switching and frequency/response characteristics.
2Adaptability or versatility
If switched capacitor networks are reconfigured to switch between output modes, then output mode versatility is improved, but circuit complexity increases
Solution Approach 1:
The differential amplifier output stage is designed with multi-functionality to handle both fully differential and single-ended output modes using the same switched capacitor networks. By making the output stage universal, the patent avoids duplicating switched capacitor networks for different output modes, thus reducing circuit complexity while maintaining output mode versatility.
3Ease of operation
If output stages are disabled in single-ended mode, then ease of operation is improved, but common mode feedback circuitry becomes unnecessary (potential complexity issue)
Solution Approach 1:
The common mode feedback circuitry is dynamically enabled or disabled based on the output mode. In fully differential mode, the common mode feedback is active to maintain proper operating points. In single-ended mode, it is disabled since it becomes unnecessary. This dynamic adjustment simplifies the circuit in single-ended mode while maintaining proper operation in differential mode.
Data Source
AI summary
An analog signal processing block with differential signal inputs and including a differential amplifier with differential inputs is disclosed which is configurable to operate either in a differential output mode or in a single-ended output mode without affecting the desired frequency and time characteristics as determined by the switched capacitor networks. The analog signal processing block includes a pair of switched capacitor networks each having one of the differential signal inputs, an input-sided terminal connected to one of the differential inputs of the differential amplifier and an output-sided terminal. The output-sided terminal of a first one of the switched capacitor networks is connected to an output of the differential amplifier. The output-sided terminal of a second one of the switched capacitor networks is connected to a complementary output of the differential amplifier when configured to differential output mode, and connected to a reference potential when configured to the single-ended mode. In this way, an application can use an analog signal processing block in either of the fully differential and single-ended output modes without the need to reconfigure the switched capacitor networks for a desired frequency and time response characteristic.