Voltage Regulator Noise Reduction via Switched Reference Isolation
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Solution Overview
Problem
Conventional voltage regulators in integrated electronic semiconductor devices face challenges in minimizing noise at their output without affecting the shared reference voltage, leading to instability and inaccurate processing of input reference voltages due to kickback noise.
Innovation Solution
A voltage regulator circuit incorporating a differential error amplifier, a feedback circuit with a voltage divider and feedforward capacitor, an active discharging transistor, and a switch mechanism that disconnects the coupling capacitor path between the regulator output and reference voltage when the regulator is turned off, effectively eliminating noise from the output and preventing it from affecting the reference voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low-pass filter is added to the output of the voltage reference circuit to reduce noise, then noise reduction is improved, but the filter does not eliminate the undesirable noise and may affect the reference voltage stability
Solution Approach 1:
The patent applies preliminary action by disconnecting the coupling capacitor path before noise can affect the reference voltage. The switch mechanism proactively opens the coupling path between the regulator output and reference voltage when the regulator is turned off, preventing kickback noise from propagating to the shared reference voltage before it can cause instability.
Solution Approach 2:
The patent extracts the noise isolation function by using a dedicated switch mechanism that physically disconnects the coupling capacitor path from the reference voltage when the regulator is off. This separates the noise source (regulator output) from the sensitive component (reference voltage) through an explicit isolation barrier.
2Object-affected harmful factors
If buffers or additional circuits are added to eliminate noise from the output, then noise reduction is improved, but additional power consumption and chip resources are required
Solution Approach 1:
The patent applies self-service by using the existing regulator output switching mechanism to control the isolation switch. The same signal that turns the regulator off also triggers the disconnection of the coupling capacitor path, making the noise protection function self-activating without requiring separate control circuits or additional power consumption.
Solution Approach 2:
The patent merges the noise isolation function with the existing regulator control logic. The switch mechanism is integrated into the regulator's existing control path, so that the noise protection feature is activated automatically by the regulator's own on/off control signal, combining multiple functions into a unified control structure.
3Object-affected harmful factors
If additional circuits are added to eliminate noise from the output, then noise reduction is improved, but chip layout area increases
Solution Approach 1:
The patent applies multi-functionality by designing the switch mechanism to serve dual purposes: controlling the regulator output and isolating the reference voltage from noise. The same switching element performs both the primary regulator control function and the secondary noise isolation function, eliminating the need for separate dedicated noise filtering circuits.
Solution Approach 2:
The patent uses the coupling capacitor path as an intermediary element that can be selectively connected or disconnected. This intermediary structure allows the reference voltage to be coupled to the regulator output when needed while providing a controlled isolation path when the regulator is off, managing the trade-off between noise protection and circuit integration.
Data Source
AI summary
A voltage regulator circuit comprises a regulator output; an amplifier that is activated in response to a first signal and inactivated in response to a second signal, the error amplifier having a first input for receiving a reference voltage, a second input for receiving a feedback voltage, and an output that generates a differential with respect to the reference voltage and the feedback voltage; an active discharging transistor that, in response to a falling slope of the electronic signal, discharges a present electronic signal at the regulator output; and a first switch at the output of the amplifier that is in open state in response to a receipt of the second signal to disconnect a coupling capacitor path between the regulator output and the reference voltage to negate an effect of noise on the reference voltage in response to the falling slope of the electronic signal.