Current Regulator Circuit for Power Rail Noise Isolation
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Solution Overview
Problem
Integrated circuit (IC) devices are susceptible to electromagnetic interference due to noise on power rails, which can cause faulty operations, and existing voltage regulators do not completely eliminate noise, especially outside a narrow operating bandwidth.
Innovation Solution
A current regulator is introduced between the voltage regulator and the load to isolate them and suppress noise on the power rail by using a clamp circuit that mirrors current changes to adjust the feedback signal and modulate the voltage drop across a power transistor, thereby maintaining a constant voltage level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If voltage regulators are used to reduce noise on power rails, then noise suppression is improved, but noise outside the narrow operating bandwidth remains
Solution Approach 1:
A current regulator is introduced as an intermediary component between the voltage regulator and the load. The current regulator includes a sense amplifier that detects noise on the power rail and a PFET that adjusts current flow based on the detected noise, thereby suppressing noise across a broader frequency range than traditional voltage regulators alone
Solution Approach 2:
The sense amplifier continuously monitors the power rail for noise and provides feedback to the PFET gate. This feedback mechanism enables the current regulator to dynamically adjust its current flow to counteract noise disturbances, improving noise suppression effectiveness
2Object-affected harmful factors
If multiple voltage regulators are provided at different voltage levels to isolate noisy circuits, then noise isolation is improved, but device complexity increases
Solution Approach 1:
The current regulator serves multiple functions: it acts as a noise filter on the power rail, provides current regulation, and isolates noisy digital circuits from sensitive analog circuits. This multi-functionality reduces the need for separate voltage regulators for each function
Solution Approach 2:
The current regulator with the PFET acts as an intermediary between noisy digital circuits and clean analog circuits. The PFET dynamically controls current flow to block noise propagation while maintaining proper power supply to both circuit types
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces noise on the power rail, leading to more reliable operations of IC circuits and less electromagnetic interference, improving the overall electromagnetic compatibility of the IC device.
Implementation Method 1
using a clamp circuit that mirrors current changes to adjust the feedback signal and modulate the voltage drop across a power transistor
Data Source
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AI summary
A current regulator circuit (120, 200) to improve electromagnetic compatibility performance operation of an IC device includes an input to receive a regulated voltage signal, an output to provide an output voltage at a desired voltage level, the output voltage exhibiting noise from a load (130), a first field effect transistor FET (122, 220) including a first source electrode coupled to the input, a first drain electrode coupled to the output, and a first gate electrode, a voltage clamp circuit (123, 126, 127, 210) coupled to the output, the voltage clamp circuit (123, 126, 127, 210) configured to conduct a varying current based upon the noise, a constant current source (129) to provide a constant current, and a second FET (128, 222) including a second source electrode coupled to the output, a second drain electrode coupled to the constant current source (129) and to the first gate electrode, and a second gate electrode coupled to the voltage clamp circuit (123, 126, 127, 210) to mirror the varying current in the second FET (128, 222).