Charge-Pump Circuit Alternating Clock and Sensing Signals for TDDI
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Solution Overview
Problem
Existing charge-pump circuits face challenges in efficiently driving touch and display panels with voltage spans greater than 40 volts, particularly when integrated with TDDI systems, while maintaining high efficiency.
Innovation Solution
A charge-pump circuit design incorporating a clock generator, sensing waveform generator, first and second diodes, and capacitors, where the clock signal alternates with the sensing signal to generate a voltage span greater than 32 volts, utilizing diode threshold voltage drops to achieve higher output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional charge-pump circuit is used in TDDI, then the circuit simplicity and efficiency are maintained, but the voltage span is limited to 32 volts and cannot drive panels requiring more than 40 volts
Solution Approach 1:
The charge pump circuit is divided into multiple stages (first charge pump stage and second charge pump stage), where each stage contributes to the overall voltage multiplication. This segmentation allows the circuit to achieve higher voltage spans (exceeding 40V) by cascading multiple voltage multiplication stages, directly resolving the limitation of conventional single-stage charge pumps.
Solution Approach 2:
The patent combines the charge pump functionality with the TDDI driver circuit by integrating the charge pump stages within the driver architecture. The clock generator, sensing waveform generator, and charge pump stages are merged into a unified circuit structure, enabling the driver to simultaneously perform touch sensing and display driving with extended voltage capability.
2Adaptability or versatility
If the voltage span is increased to drive panels requiring more than 40 volts, then the adaptability to TDDI is improved, but the circuit complexity increases
Solution Approach 1:
The charge pump circuit is designed to serve multiple functions within the TDDI system: it provides voltage multiplication for display driving, enables touch sensing through the sensing waveform generator, and maintains compatibility with existing TDDI architectures. This multi-functionality allows the circuit to adapt to TDDI requirements without requiring completely separate dedicated circuits for each function.
Solution Approach 2:
The circuit employs dynamic clock signaling where the clock generator produces alternating high and low states that dynamically control the switching of diodes and capacitors in the charge pump stages. This dynamic operation enables the circuit to achieve variable voltage outputs and adapt to different operating conditions, maintaining flexibility despite the increased structural complexity.
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 proposed charge-pump circuit effectively provides a larger voltage span, enabling efficient operation for touch and display driver integration systems beyond the typical 32-volt limit, while maintaining high efficiency.
Implementation Method 1
The first capacitor has a first plate electrically coupled to receive the clock signal, and a second plate electrically connected to an anode of the first diode at an intermediate node. The second capacitor has a first plate electrically coupled to receive the sensing signal, and a second plate electrically connected to an anode of the second diode at an output node.
Implementation Method 2
utilizing diode threshold voltage drops to achieve higher output voltages
Data Source
AI summary
A charge-pump circuit includes a clock generator that generates a clock signal; a sensing waveform generator that generates a sensing signal; a first diode having a cathode electrically connected to a predetermined low voltage; a first capacitor having a first plate electrically coupled to receive the clock signal, and a second plate electrically connected to an anode of the first diode; a second diode having a cathode electrically connected to the second plate of the first capacitor; and a second capacitor having a first plate electrically coupled to receive the sensing signal, and a second plate electrically connected to an anode of the second diode at an output node. The clock signal being generated in a charge-pump period alternates in time with the sensing signal being generated in a touch-sensing period.