Charge Injection Compensation Circuit for Wide Supply Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic switches, particularly those using semiconductor field effect transistors, face challenges in compensating for charge injection across a wide range of supply voltages without requiring changes to their design parameters, leading to potential disruptions in signal integrity and accuracy.
Innovation Solution
A charge injection compensation circuit that includes a main switch, a charge storage device, and a pulse generator circuit to manage charge transfer and dissipation, ensuring zero net charge injection regardless of supply voltage through controlled switching and dissipation mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a basic capacitor compensation configuration is used to compensate for charge injection, then charge injection can be compensated at a single voltage (e.g., mid-rail voltage), but the compensation is not effective across a wide range of supply voltages
Solution Approach 1:
The patent makes the compensation circuit dynamic by introducing a resistor that switches between connected and disconnected states based on the supply voltage level. When the supply voltage exceeds a threshold, the resistor connects to ground to dissipate excess charge; when the voltage is within the normal range, the resistor disconnects to avoid affecting normal operation. This dynamic adaptation allows the circuit to maintain compensation effectiveness across a wide supply voltage range rather than being fixed for a single voltage level.
2Measurement precision
If a resistor is switched between the output of the parallel switch and ground for a predefined period of time to compensate for charge injection, then charge injection can be compensated, but the compensation is only effective at one supply voltage unless the value of the resistor is varied with supply voltage
Solution Approach 1:
The patent implements a self-service mechanism where the compensation circuit automatically detects and responds to supply voltage conditions without external control. A voltage detection circuit monitors the supply voltage and automatically activates the resistor connection when voltage exceeds the threshold, eliminating the need for complex external control circuits or manual adjustment. The circuit serves itself by autonomously determining when compensation is needed and executing the appropriate action.
3Measurement precision
If PFET device is sized with a larger width than NFET device to achieve same on resistance, then the additional charge injected by PFET device can be compensated at a single voltage, but the compensation cannot adapt to varying supply voltages
Solution Approach 1:
The patent changes the operational parameters of the compensation circuit based on supply voltage conditions. Specifically, it modifies the resistance connection state (connected or disconnected) according to the supply voltage level. This parameter change allows the circuit to adapt its compensation behavior to different voltage conditions, maintaining effectiveness whether the supply voltage is at nominal levels or elevated beyond the threshold.
Data Source
AI summary
A charge injection compensation circuit compensates for charge injection by a field-effect transistor (FET) switch regardless of a supply voltage. The charge injection compensation circuit includes a main switch that injects charge into an electronic circuit when switched off, and a charge storage device that stores the injected charge until it can be dissipated to a dissipating node. Upon the main switch being controlled to switch off, a pulse generator circuit controls a charge storage switch to switch on to transfer the charge injected from the main switch to the charge storage device and then switch off. A dissipation circuit dissipates the charge from the charge storage device to a dissipating node.