Voltage Regulator Feedforward Mirror for Fast Transient Stability
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Solution Overview
Problem
Existing voltage regulators for integrated circuits struggle to maintain stable output voltage in the face of fast line and load transients, particularly in harsh automotive environments where electromagnetic interference (EMI) is prevalent.
Innovation Solution
The proposed voltage regulator incorporates a feedforward Wilson current mirror and a flipped voltage follower (FVF) with a super source follower (SSF) loop. The feedforward Wilson current mirror generates a compensation current in response to voltage transients, which helps stabilize the output voltage by controlling the gate voltage of the pass transistor. The FVF and SSF loop work together to rapidly pull down transient peaks at the output terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional voltage regulator is used, then the circuit is simple, but the output voltage becomes unstable during fast line and load transients
Solution Approach 1:
The feedforward Wilson current mirror generates a compensation current in advance in response to voltage transients at the supply terminal. This preliminary action occurs before the transients reach the output, allowing the gate voltage of the pass transistor to be adjusted proactively, thereby maintaining output voltage stability without requiring complex feedback mechanisms.
Solution Approach 2:
The feedforward Wilson current mirror acts as an intermediary between the supply voltage terminal and the pass transistor gate. It processes voltage transients and generates compensation currents that mediate the control of the pass transistor, isolating the output from direct exposure to supply transients while maintaining stability.
2Stability of the object's composition
If the feedforward Wilson current mirror is added to suppress voltage transients, then the output voltage stability improves, but the power consumption increases
Solution Approach 1:
The feedforward Wilson current mirror applies partial action by generating compensation currents only when voltage transients are detected at the supply terminal. Rather than continuously adjusting the pass transistor, the circuit activates selectively during transient events, reducing unnecessary power consumption while maintaining output stability during critical moments.
3Stability of the object's composition
If the feedforward Wilson current mirror is used to respond to voltage transients, then the output voltage remains stable, but the device complexity increases
Solution Approach 1:
The feedforward Wilson current mirror performs multiple functions within a single circuit block: it detects voltage transients at the supply terminal, generates compensation currents, and controls the pass transistor gate. This multi-functionality reduces the need for separate detection, processing, and control circuits, thereby limiting the increase in overall device complexity while achieving output voltage stability.
Data Source
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AI summary
A voltage regulator for outputting a regulated output voltage to an integrated circuit, the voltage regulator comprising: a voltage supply terminal for receiving a supply voltage; an output terminal for outputting the regulated output voltage; a reference terminal; a feedforward Wilson current mirror comprising: a Wilson current mirror with an input current terminal and an output current terminal; an input current source coupled between the supply voltage terminal and the input current terminal of the Wilson current mirror; a feedforward capacitor arranged in parallel with the input current source; and an output current transistor with a conduction channel coupled between the supply voltage terminal and the output current terminal of the Wilson current mirror; and a flipped voltage follower, FVF, comprising: a pass transistor comprising a conduction channel coupled between the supply voltage terminal and the output terminal; a first FVF transistor with a conduction channel coupled between the output voltage and a FVF node; a second FVF transistor with a conduction channel coupled between a gate of the pass transistor and the FVF node; a third FVF transistor with a conduction channel coupled between the supply voltage terminal and the gate of the pass transistor, wherein a gate of the third FVF transistor is coupled to a gate of the output current transistor; and a FVF current source coupled between the FVF node and the reference terminal.