Error Amplifier Current Sensing for Higher DC Gain Bandwidth
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Solution Overview
Problem
Current error amplification and compensation circuits for voltage regulators are large in size, have insufficient DC gain, and/or have limited frequency range.
Innovation Solution
A compact error amplification and/or compensator circuit is designed, featuring a differential error amplifier with current sensing and processing units, and an adjustment resistor to enhance DC gain and frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If current error amplification and compensation circuits are used, then the circuit provides error amplification and compensation functions, but the circuit size is large
Solution Approach 1:
The patent changes the operating parameters by using a differential error amplifier configuration with specific transistor sizing and biasing conditions. The amplifier operates in a differential mode with controlled current mirrors that enable high DC gain while maintaining compact dimensions. The key parameter change is the use of differential signaling and current-mode operation to achieve superior performance in a smaller footprint.
Solution Approach 2:
The compensation circuit is segmented into distinct functional blocks: a differential error amplifier stage, current mirror circuits for gain enhancement, and a compensation network with separate RC components. This segmentation allows each block to be optimized independently for size and performance, achieving high DC gain through the differential stage while keeping the overall circuit compact.
2Speed
If current error amplification and compensation circuits are used, then the circuit provides error amplification and compensation functions, but the frequency range of mid-band gain is limited
Solution Approach 1:
The circuit employs dynamic compensation techniques where the differential error amplifier maintains constant mid-band gain across a wide frequency range through active feedback mechanisms. The compensation network uses RC time constants that are optimized to extend the bandwidth while the current mirrors dynamically adjust to maintain gain stability. This dynamic operation enables extended frequency range without proportionally increasing circuit size.
3Reliability
If current error amplification and compensation circuits are used, then the circuit provides error amplification and compensation functions, but the DC gain is insufficient
Solution Approach 1:
The differential error amplifier incorporates feedback mechanisms through current mirrors that sense the output current and feed it back to the input stage. This feedback loop significantly enhances the DC gain by reducing the output impedance and improving the overall amplification factor. The feedback is implemented in a controlled manner that does not excessively increase circuit complexity, as it reuses existing transistor structures in the differential pair.
Data Source
AI summary
The present document describes an error amplification circuit for a voltage regulator. The error amplification circuit comprises a differential error amplifier having a first input for a feedback signal of the voltage regulator and having a second input for a reference signal, wherein the differential error amplifier is configured to provide an amplifier output current in dependence of the signals at the first input and at the second input. Furthermore the error amplification circuit comprises a current sensing unit configured to sense the amplifier output current to provide a sensed current, a processing unit configured to process the sensed current to provide a processed current, and an adjustment resistor which is arranged in series with the second input of the differential error amplifier and to which the processed current is applied.