Display Pixel Voltage Regulator With Load-Adaptive Phase Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage regulators for display panels face instability in maintaining a constant pixel power supply voltage when load currents change, leading to unstable operation.
Innovation Solution
A voltage regulator design that includes a voltage divider, error amplifier, variable phase compensating circuit, source follower buffer, and pass transistor, along with compensation capacitors, to adjust the amplifier output voltage based on load current and maintain a stable pixel power supply voltage across the entire load current range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional voltage regulator is used to maintain constant pixel power supply voltage, then the voltage level can be regulated, but the operation becomes unstable when load current changes
Solution Approach 1:
The patent implements a variable phase compensating circuit that dynamically adjusts the phase margin according to load current changes. The circuit transitions from a first phase compensating circuit for light load conditions to a second phase compensating circuit for heavy load conditions, enabling the voltage regulator to maintain stability across the entire load current range from minimum to maximum load current.
2Adaptability or versatility
If the load current changes from minimum to maximum, then the voltage regulator can handle varying power demands, but the pixel power supply voltage varies and operation becomes unstable
Solution Approach 1:
The variable phase compensating circuit dynamically switches between different phase compensating circuits based on load current magnitude. For light load currents, a first phase compensating circuit is used, and for heavy load currents, a second phase compensating circuit is activated, ensuring the phase margin remains within the stable range (45° to 135°) across all operating conditions.
Solution Approach 2:
The patent employs a feedback mechanism where the phase compensating circuit monitors load current changes and adjusts the compensation network accordingly. This feedback control ensures that the voltage regulator maintains constant pixel power supply voltage despite variations in load current from minimum to maximum levels.
3Reliability
If the phase margin is not properly adjusted for varying load currents, then the circuit design is simpler, but the voltage regulator cannot operate stably throughout the entire load current range
Solution Approach 1:
The phase compensating circuit is segmented into multiple sub-circuits: a first phase compensating circuit for light load conditions and a second phase compensating circuit for heavy load conditions. This segmentation allows each sub-circuit to be optimized for its specific operating range, improving overall stability while managing complexity through modular design.
Solution Approach 2:
The patent changes the parameters of the phase compensating circuit based on load current magnitude. By switching between different circuit configurations with appropriate phase compensation values, the system maintains optimal phase margin (45° to 135°) across varying load conditions without requiring an overly complex adaptive circuit.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A voltage regulator for outputting a pixel power supply voltage supplied to pixels of a display panel is disclosed. The voltage regulator includes a voltage divider configured to generate a feedback voltage by dividing the pixel power supply voltage, an error amplifier configured to generate an amplifier output voltage by comparing a reference voltage and the feedback voltage, a variable phase compensating circuit configured to adjust the amplifier output voltage according to a load current, a source follower buffer configured to generate a control voltage by buffering the adjusted amplifier output voltage, and a pass transistor configured to output, as the pixel power supply voltage, an input voltage based on the control voltage.