Sampling Circuit Precharge Control for Faster Settling
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Solution Overview
Problem
The existing sampling circuits face increased settling time issues when input voltage is applied from an amplifier, due to varying settling times for voltage stabilization, which affects the time required for sampling to start.
Innovation Solution
A sampling circuit design that includes a capacitor, multiple switches, and a control circuit to manage the connection states between the amplifier, voltage source, and a reference potential, allowing for controlled charging and discharging to optimize settling times based on amplifier characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor is discharged before sampling, then the output voltage fluctuation is reduced, but the settling time increases
Solution Approach 1:
The control circuit performs preliminary discharge of the capacitor by switching the first switch to off state and second switch to on state before the sampling operation. This preliminary action sets the capacitor voltage to reference potential, and after a predetermined time has elapsed, the sampling switch is turned on to perform sampling with reduced settling time
Solution Approach 2:
The circuit dynamically adjusts the discharge duration based on amplifier characteristics. The control circuit sets the discharge time according to the specific amplifier being used, optimizing the balance between voltage stability and settling time for different amplifier types
2Reliability
If the capacitor is discharged for a fixed period, then the voltage stabilization is improved, but the productivity decreases
Solution Approach 1:
The control circuit changes the discharge time parameter based on amplifier characteristics. Different amplifiers have different settling characteristics, and the control circuit adjusts the discharge duration accordingly, ensuring optimal voltage stabilization while minimizing the impact on sampling speed and overall productivity
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 significantly reduces settling time and shortens the time until sampling can begin, achieving faster stabilization of output voltage by adjusting the holding voltage of the capacitor according to amplifier characteristics without increasing current consumption or circuit area.
Implementation Method 1
a capacitor, charged by an input voltage from the amplifier
Data Source
AI summary
A sampling circuit includes: an amplifier, having a characteristic that settling time in a case where an output voltage of the sampling circuit is lowered and the settling time in a case where the output voltage is raised are different; a capacitor, charged by an input voltage from the amplifier; a first switch, switching a connection state between an output of the amplifier and the capacitor; a second switch, connected in parallel with the capacitor, and switching a connection state between the capacitor and a reference potential part whose potential is set according to the characteristic of the amplifier; and a control circuit, controlling switching of each switch. The control circuit performs a first control that switches the first switch off and the second switch on and then performs a second control that switches the first switch on and the second switch off.