ADC Charge Compensation Circuit for Reference Voltage Stability
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Solution Overview
Problem
Analog-to-digital converters face reliability issues due to voltage drops caused by discharging paths from reference voltage to ground, degrading the stability of the reference voltage during conversion processes.
Innovation Solution
A charge compensation circuit is introduced, comprising capacitors and logic circuits that adjust voltages at their terminals based on control signals generated from output bits of the ADC, using buffers between supply and ground voltages to stabilize the reference voltage through negative feedback mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conversion process is performed by the analog-to-digital converter, then the analog signal is converted to digital signal, but discharging paths are formed from reference voltage to ground voltage causing voltage-drop and degrading reliability
Solution Approach 1:
The patent implements a charge compensation circuit that uses feedback mechanisms to detect voltage drops across capacitors connected to the reference voltage node and automatically compensates by transferring charge from compensation capacitors. The control logic monitors the voltage status and activates compensation switches to restore the reference voltage, creating a closed-loop feedback system that maintains voltage stability during the conversion process.
Solution Approach 2:
The patent employs compensation capacitors that store charge during normal operation and release it when voltage drops occur. The circuit discards the temporary voltage drop condition by recovering charge from the compensation capacitors through controlled discharge paths, effectively restoring the reference voltage without interrupting the overall conversion process.
2Ease of operation
If discharging paths are formed from reference voltage to ground voltage, then conversion operation is enabled, but voltage-drop occurs degrading reference voltage reliability
Solution Approach 1:
The patent introduces compensation capacitors as intermediary elements between the reference voltage node and ground. These capacitors act as charge reservoirs that can quickly supply or absorb charge to maintain voltage stability. The control logic and switches serve as intermediaries that manage charge transfer between the compensation capacitors and the reference voltage node, preventing direct voltage drops during conversion operations.
Solution Approach 2:
The compensation capacitors are pre-charged to the reference voltage level before conversion operations begin. This preliminary charging ensures that when discharging paths are activated during conversion, the compensation capacitors can immediately provide charge compensation without delay, maintaining reference voltage stability proactively rather than reactively.
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 proposed solution effectively stabilizes the reference voltage, enhancing the reliability and accuracy of the analog-to-digital conversion process by compensating for voltage variations caused by discharging paths.
Implementation Method 1
A first terminal of the first capacitor is coupled to a reference voltage of the analog-to-digital converter. The first logic circuit adjusts a voltage at a second terminal of the first capacitor according to a first control signal.
Implementation Method 2
The first logic circuit includes a first buffer coupled between a supply voltage and a ground voltage. An input terminal of the first buffer is arranged for receiving the first control signal, and an output terminal of the first buffer is coupled to the second terminal of the first capacitor.
Data Source
AI summary
A charge compensation circuit for use in an analog-to-digital converter (ADC) includes at least one capacitor and at least one logic circuit. A first terminal of the capacitor is coupled to a reference voltage of the analog-to-digital converter. The logic circuit is configured to adjust a voltage at a second terminal of the capacitor according to a control signal. The control signal is determined according to at least one output bit from the analog-to-digital converter.