Gamma Voltage Supply Circuit Stabilization via Internal DC-DC Conversion
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Solution Overview
Problem
Existing power management ICs face instability in gamma voltage supply due to sudden changes in external voltage, leading to degraded image quality, and current solutions with filters or large capacitors increase chip size.
Innovation Solution
A power management IC with a gamma voltage supply circuit that includes an internal voltage generator, digital-to-analog converter, regulator, resistor string, switch circuit, and gamma buffers to generate and stabilize gamma voltages using a boosted internal voltage, reducing chip size and maintaining stable voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter including a resistor and a capacitor is mounted in the gamma voltage supply circuit to prevent gamma voltage destabilization, then the stability of gamma voltage is improved, but the chip size is increased
Solution Approach 1:
The patent extracts the problematic external voltage input and replaces it with an internal voltage generator that produces voltage internally through a DC-DC converter. This eliminates the need for external voltage inputs and associated filter circuits, thereby maintaining gamma voltage stability without increasing chip size with large capacitors.
Solution Approach 2:
The patent introduces a DC-DC converter as an intermediary component that converts a stable reference voltage into the required internal voltage for gamma voltage generation. This intermediary conversion process ensures stable gamma voltage output without requiring large filter capacitors, thus resolving the contradiction between stability and chip size.
2Reliability
If a capacitor having a large capacity is used to sufficiently overcome the instability of the gamma voltage, then the stability of gamma voltage is improved, but the chip size is inevitably increased
Solution Approach 1:
The patent removes the need for large capacity capacitors by extracting the voltage instability problem at its source - the external voltage input - and replacing it with an internal voltage generation system that inherently provides stable voltage without requiring large filtering components.
Solution Approach 2:
The patent substitutes the passive mechanical filtering approach (using large capacitors) with an active electronic voltage conversion system (DC-DC converter). This substitution maintains voltage stability through active regulation rather than passive energy storage, thereby avoiding the need for large capacitors and reducing chip size.
3Device complexity
If the gamma voltage supply circuit uses external voltage to generate gamma voltage, then the circuit complexity is reduced, but the gamma voltage becomes destabilized due to sudden changes in external voltage
Solution Approach 1:
The patent extracts the external voltage dependency and replaces it with an internal voltage generation system. The DC-DC converter generates stable internal voltage from a reference voltage source, eliminating the destabilizing influence of external voltage fluctuations while maintaining relatively simple circuit architecture.
Solution Approach 2:
The patent implements self-service by enabling the power management IC to generate its own internal voltage and gamma voltage internally through the DC-DC converter, rather than relying on external voltage inputs. This self-sufficient approach ensures stable gamma voltage generation while keeping the circuit design relatively simple.
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
The solution effectively stabilizes gamma voltage supply, improving image quality while reducing chip size by eliminating the need for large capacitors and filter circuits, thus addressing the instability issues and size constraints of existing technologies.
Implementation Method 1
an internal voltage generator configured to generate a boosted internal voltage through an external voltage
Implementation Method 2
a regulator configured to supply a regulating voltage by regulating an internal voltage obtained by boosting an external voltage
Implementation Method 3
a resistor string configured to generate the gamma voltages corresponding to the plurality of channels using the regulating voltage
Data Source
AI summary
The present invention provides a gamma voltage supply circuit capable of stably supplying a gamma voltage in response to the change of external voltage and a power management IC including the same. The gamma voltage supply circuit generates a regulating voltage using an internal voltage which is not influenced by the variation in load of a source driver IC, and generates a gamma voltage using the regulating voltage.