Digital Regulator Replica Circuit for Stable Low-Voltage LDO Control
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Solution Overview
Problem
Digital LDOs face challenges in performance correction without output changes, stability due to multiloop control, large area requirements, and high power consumption, especially in low voltage operations.
Innovation Solution
A digital control regulator with a first A/D converter, output stage circuit, replica circuit, and control circuit that adjusts gain based on differential voltage signals to stabilize and reduce ripple and droop characteristics, using circuits with matching configurations and resistance values to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the performance of the output stage circuit is increased to enhance transient response characteristics, then the transient response is improved, but the ripple voltage is increased and stability is deteriorated
Solution Approach 1:
The patent employs a replica circuit that copies the configuration and characteristics of the output stage circuit. By measuring the on-resistance of the replica circuit and using this information to adjust the control signal, the system can optimize transient response without directly modifying the output stage circuit, thereby avoiding ripple voltage increase and stability deterioration.
2Stability of the object's composition
If a multiloop control configuration is implemented to enhance stability, then stability is improved, but the device area increases and power consumption increases
Solution Approach 1:
The patent extracts the performance measurement function into a separate replica circuit that operates independently from the main control loop. This allows the system to achieve stability enhancement through digital measurement and control without requiring additional analog control loops, thereby reducing device area and power consumption compared to traditional multiloop control configurations.
3Measurement precision
If analog control circuits are used to adjust performance parameters, then correction accuracy is improved, but the device area increases and power consumption increases
Solution Approach 1:
The patent replaces analog control circuits with digital control mechanisms. The replica circuit measures on-resistance characteristics, and the control circuit uses digital signal processing to generate control signals that adjust the output stage circuit's gain. This substitution maintains correction accuracy while significantly reducing device area and power consumption, making it suitable for low voltage operation.
Data Source
AI summary
Provided is a low voltage and compact digital control regulator that achieves enhanced stability and reduced variations in ripple voltage and droop characteristics. The digital control regulator includes a first A/D converter configured to generate a first digital signal according to a differential voltage between an output voltage and a first reference voltage, an output stage circuit configured to generate the output voltage, a replica circuit having the same circuit configuration as the output stage circuit and configured to output a replica voltage related to the output voltage, a second A/D converter configured to generate a second digital signal according to a differential voltage between the replica voltage and a second reference voltage, and a control circuit configured to generate a control signal for controlling a gain of the output stage circuit, according to the first digital signal and the second digital signal.