Bilateral Op-Amp Current Source Disabled-Mode Error Reduction
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Solution Overview
Problem
High-voltage bilateral operational amplifiers experience significant offset voltage errors when operating in a disabled mode, leading to unwanted current amplification and inefficiencies.
Innovation Solution
Implementing an analog switch to operate the operational amplifier in a disabled mode by disconnecting input signals, reducing feed-forward gain and eliminating common-mode voltage transfer, thereby minimizing error current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operational amplifier is kept connected to reference voltage and command voltage in disabled mode, then the circuit remains ready for immediate operation, but offset voltage errors are amplified producing unwanted output current
Solution Approach 1:
The patent extracts and removes the harmful offset voltage amplification by disconnecting the command voltage input from the operational amplifier when in disabled mode. The analog switch opens the command voltage path, preventing the offset voltage from being amplified and appearing as unwanted output current, while keeping the reference voltage connection intact for rapid reactivation.
Solution Approach 2:
The patent implements dynamic switching of the command voltage connection based on the enabled/disabled state. An analog switch controlled by an enable signal dynamically connects or disconnects the command voltage input to the operational amplifier, allowing the circuit to adapt its configuration to minimize error current during disabled periods while maintaining operational readiness.
2Object-generated harmful factors
If high-voltage switches are used to disconnect input signals in disabled mode, then error current is reduced, but device complexity and cost increase
Solution Approach 1:
The patent changes the voltage parameter of the switching mechanism from high-voltage to low-voltage (5V) operation. By using a 5V analog switch to control the command voltage path rather than using high-voltage switches, the patent achieves error current reduction while significantly simplifying the switching mechanism and reducing overall device complexity.
Solution Approach 2:
The patent introduces a 5V analog switch as an intermediary element to control the command voltage path. This intermediary switch operates at low voltage and provides precise control over the operational amplifier's input connections without requiring complex high-voltage switching mechanisms, thereby reducing device complexity while achieving the desired error current reduction.
Data Source
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AI summary
Provided are embodiments that include a circuit configured to operate in a disabled mode error reduction for high-voltage bilateral operational amplifier current source. The circuit (200) includes an operational amplifier (110), and a switching circuit coupled to the operation amplifier, wherein the switching circuit is operable in a normal mode and a disabled mode, wherein the disabled mode reduces error current at the output of the operational amplifier. Also provided are embodiments for a method for operating a circuit in a disabled mode for error reduction.