Voltage Regulator Current Mirror for Overshoot Smoothing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional voltage regulators face challenges in effectively managing overshoot events, particularly in digital circuits, due to limitations in amplifier speed and power consumption, which result in unreliable voltage regulation and increased parasitic capacitances.
Innovation Solution
A voltage regulator design that senses the load current, creates an attenuated replica, and filters it to re-inject it as additional load, slowing down the overall load current response to overshoot events, thereby smoothing the load current profile and allowing the amplifier to track it more easily.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional voltage regulators are used to prevent overshoot events, then the response speed can be improved, but the power consumption increases and the amplifier speed is limited
Solution Approach 1:
The patent introduces an intermediary circuit that includes a current mirror and a capacitor. This intermediary circuit senses the load current and generates a compensating current that is coupled to the bias current generator, thereby mediating between the load current variations and the amplifier to prevent overshoot events without requiring the amplifier itself to respond faster
Solution Approach 2:
The patent implements preliminary action by sensing the load current before it causes significant overshoot and generating a compensating current in advance. The current mirror and capacitor combination prepares the compensating current that is then coupled to the bias current generator to counteract the load current variations before they result in problematic overshoot events
2Speed
If larger currents are used to address overshoot events faster, then the response speed improves, but the transistor size increases leading to larger parasitic capacitances
Solution Approach 1:
The patent uses a current mirror to create a copy of the load current. This copied current is then processed through a capacitor and coupled to the bias current generator. By working with a copied and scaled version of the load current rather than the full load current directly, the circuit achieves fast response without requiring large transistors that would introduce significant parasitic capacitances
3Speed
If the amplifier speed is increased to track load current variations faster, then the overshoot performance improves, but the power consumption increases
Solution Approach 1:
The patent introduces an intermediary circuit that includes a current mirror and a capacitor. This intermediary circuit senses the load current and generates a compensating current that is coupled to the bias current generator, thereby mediating between the load current variations and the amplifier to prevent overshoot events without requiring the amplifier itself to respond faster
Solution Approach 2:
The patent implements feedback by continuously sensing the load current through the current mirror and capacitor combination, and using this information to adjust the bias current generator in real-time. This feedback mechanism allows the system to maintain stability and prevent overshoot without requiring the amplifier to operate at higher speeds or consume more power
Data Source
AI summary
A voltage regulator comprises an output transistor with a controlled section connected between a first supply terminal and an output terminal. An amplifier comprises a reference input and a feedback input. A current mirror comprising a replica transistor. The current mirror is configured to mirror and attenuate a load current supplied by the output transistor to the replica transistor. A filter circuit is coupled to a controlled section of the replica transistor and coupled to the feedback input of the amplifier via the output terminal.