Source Driver Power Circuit With On-Chip Charge Pump Capacitors
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Solution Overview
Problem
Existing source drive chips for OLED displays require off-chip capacitors to generate a negative voltage power supply, leading to increased costs and the risk of excessive inrush current during power-on.
Innovation Solution
The source drive chip incorporates a power supply circuit with a charge pump, a reference source generation circuit, and a low dropout regulator, where at least two capacitors in the charge pump are converted from off-chip to on-chip capacitors, reducing the need for external capacitors and optimizing the charge pump circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If off-chip capacitors are used in the charge pump to generate negative voltage power supply, then the circuit can be simplified and ease of manufacture is improved, but the chip cost increases and panel-level area is occupied
Solution Approach 1:
The patent merges the charge pump capacitors from off-chip components into on-chip integrated capacitors. Specifically, the first capacitor is integrated into the charge pump circuit on the chip, and the second capacitor is integrated into the low dropout regulator on the chip, eliminating the need for separate off-chip capacitors and reducing panel-level area occupation.
Solution Approach 2:
The patent implements nesting by integrating capacitor functions directly within the chip architecture. The charge pump capacitor is nested within the charge pump circuit block, and the regulator capacitor is nested within the low dropout regulator block, creating a compact integrated structure that eliminates external components.
2Adaptability or versatility
If the charge pump provides negative voltage to both the reference source generation circuit and the low dropout regulator, then voltage conversion capability is improved, but large inrush current is generated during power-on which harms circuit safety
Solution Approach 1:
The patent segments the power supply architecture by creating two independent power supply paths: the charge pump provides negative voltage only to the reference source generation circuit, while the low dropout regulator receives its negative voltage directly from the external negative voltage power supply. This segmentation prevents the charge pump from bearing the full power supply burden and eliminates large inrush current generation.
Solution Approach 2:
The patent introduces the low dropout regulator as an intermediary component that bridges the external negative voltage power supply and the load circuit. The regulator independently handles the power supply function for the load, preventing direct large current draw from the charge pump during power-on.
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
This solution reduces the number of off-chip capacitors, lowering the chip's cost and improving its competitiveness while preventing large inrush currents and ensuring circuit safety.
Implementation Method 1
a first capacitor integrated into the charge pump circuit on the chip and configured to store energy in a first manner; a second capacitor integrated into the charge pump circuit on the chip and configured to store energy in a second manner
Implementation Method 2
the low dropout regulator is coupled to the load circuit, and the low dropout regulator is configured to output a power supply voltage to the load circuit based on the reference voltage and an external negative voltage power supply
Data Source
AI summary
A source drive include a power supply circuit that includes a charge pump, a reference source generation circuit, and a low-dropout (LDO) regulator. The charge pump includes at least two on-chip capacitors, is coupled to the reference source generation circuit, and is configured to provide a negative voltage level for the reference source generation circuit based on an external positive voltage power supply. The reference source generation circuit is coupled to the LDO regulator. The reference source generation circuit is configured to provide a reference voltage for the LDO regulator based on the negative voltage level. The LDO regulator is coupled to a load circuit, and the LDO regulator is configured to output a power supply voltage to the load circuit based on the reference voltage and an external negative voltage power supply.