LDO Voltage Regulator Transient Response Compensation
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Solution Overview
Problem
Conventional LDO voltage regulators have slow transient responses and instability under varying load conditions and temperature changes, which affect their ability to maintain a stable output voltage.
Innovation Solution
The LDO voltage regulator incorporates an error amplifier, power transistor, voltage division unit, compensation control unit, and bias current sources, with a voltage and temperature compensation module to generate a compensation bias current that accelerates load transient response and compensates for supply voltage and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional LDO voltage regulator design is used, then circuit simplicity and low cost are maintained, but transient response speed is slow
Solution Approach 1:
The patent segments the compensation function into separate modules: a compensation control unit that detects output voltage changes and a compensation bias current source that provides additional current to the error amplifier. This segmentation allows the transient response to be accelerated without completely redesigning the basic LDO structure, thus improving speed while controlling complexity.
Solution Approach 2:
The compensation control unit continuously monitors the output voltage and prepares the compensation bias current source to activate when voltage deviations are detected. This preliminary monitoring and readiness ensure that compensation action is initiated immediately upon transient events, accelerating the response speed without requiring permanent high-current operation that would increase overall circuit complexity.
2Reliability
If conventional LDO voltage regulator design is used, then circuit simplicity is maintained, but stability under varying loads and temperature is poor
Solution Approach 1:
The patent implements a feedback mechanism where the compensation control unit continuously monitors the output voltage and feeds this information back to control the compensation bias current source. This closed-loop feedback ensures that the regulator automatically adjusts compensation current based on actual output conditions, improving stability under varying loads and temperature while maintaining a relatively simple circuit structure.
Solution Approach 2:
The compensation bias current is dynamically adjusted based on operating conditions - it is activated only when transient events are detected and deactivated during steady-state operation. This dynamic operation improves reliability under varying conditions while avoiding the complexity of continuously active compensation circuits.
3Speed
If compensation bias current is continuously supplied to error amplifier, then transient response is accelerated, but power consumption increases
Solution Approach 1:
The compensation bias current is supplied periodically rather than continuously - it is activated only during transient events when voltage deviations are detected by the compensation control unit and deactivated during steady-state operation. This periodic action maintains fast transient response capability while significantly reducing average power consumption compared to continuous compensation current supply.
Data Source
AI summary
A low drop out (LDO) voltage regulator having an error amplifier, a power transistor, a first voltage division unit, a compensation control unit and a compensation bias current source is provided. The error amplifier generates a control voltage according to a first reference voltage and a feedback voltage. The power transistor generates an output voltage at a drain of the power transistor according to the control voltage. The first voltage division unit divides the output voltage to generate the feedback voltage. The compensation control unit generates a compensation control signal to the compensation bias current source according to the control voltage, the output voltage and a compensation bias, so as to make the compensation bias current source generate a compensation bias current, in which the compensation bias is inversely proportional to a supply voltage and ambient temperature.