Capacitive Touch Panel Boost Circuit with Integrated Charge Pumps
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Solution Overview
Problem
Capacitive touch panel detection circuits face issues with high cost, large occupied area, and electromagnetic interference due to the need for multiple ICs and off-chip ancillary components like inductors and Schottky diodes in existing boost circuits.
Innovation Solution
A boost circuit is designed with a series of charge pumps and a voltage-stabilizing circuit integrated into an IC chip, eliminating the need for off-chip components like inductors and Schottky diodes, and incorporating a voltage-stabilizing capacitor to reduce electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a typical boost circuit with inductor, Schottky diode, and capacitor is used, then high voltage can be achieved, but the number of off-chip components increases and electromagnetic interference occurs
Solution Approach 1:
The patent merges the boost circuit functions into an integrated charge pump circuit that can be fully integrated into an IC chip. Multiple charge pump stages are combined in series to achieve the required voltage multiplication, eliminating the need for separate inductors, Schottky diodes, and capacitors that would otherwise be required as off-chip components.
Solution Approach 2:
The patent replaces the traditional inductive boost mechanism with a capacitive charge pump mechanism. Instead of using an inductor to store and transfer energy magnetically, the circuit uses capacitors to store and transfer energy electrically through switching networks, thereby achieving voltage boosting without electromagnetic interference from inductive components.
2Power
If multiple ICs and off-chip ancillary components are used in the boost circuit, then high voltage can be achieved, but the occupied area and cost increase
Solution Approach 1:
The patent combines multiple functional blocks including the boost circuit, detection circuit, and control logic into a single integrated IC chip. The charge pump stages, switching networks, and energy storage capacitors are all integrated onto one chip, dramatically reducing the occupied area compared to using multiple separate ICs and off-chip components.
Solution Approach 2:
The integrated circuit performs multiple functions within a single chip: voltage boosting through the charge pump, signal detection through the detection circuit, and overall system control. This multi-functionality eliminates the need for separate dedicated components for each function, thereby reducing the total occupied area.
3Power
If traditional boost circuit components are used, then voltage boosting can be achieved, but electromagnetic interference increases
Solution Approach 1:
The patent substitutes the inductive energy transfer mechanism with a capacitive energy transfer mechanism. The charge pump uses switched capacitors to transfer energy electrically rather than magnetically, eliminating the electromagnetic radiation and interference associated with inductors while maintaining the voltage boosting function.
Solution Approach 2:
The patent extracts and removes the electromagnetic interference-generating components (inductors and Schottky diodes) from the circuit design. By using only capacitive elements and switching networks that can be integrated into the IC, the harmful electromagnetic interference is completely eliminated while the desired voltage boosting effect is preserved.
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 components, decreases electromagnetic interference, and integrates all necessary circuits into a single IC chip, enhancing efficiency and reducing costs while maintaining high voltage levels for capacitive touch panel detection.
Implementation Method 1
a first capacitor C1 and a second capacitor C2... The first capacitor C1 is connected between the second ends of the first and third switches. The second end of the fourth switch is connected with the ground. One end of the second capacitor C2 is connected with the second end of the second switch
Implementation Method 2
incorporating a voltage-stabilizing capacitor to reduce electromagnetic interference
Data Source
AI summary
The invention discloses a capacitive touch panel detection circuit and a boost circuit thereof, wherein the boost circuit comprises a plurality of charge pumps in series, a sequence circuit and a voltage-stabilizing circuit. The charge pump comprises a first switch, a second switch, a third switch, a fourth switch, a first capacitor and a second capacitor. The switches are controlled by the sequence circuit. During the first half of the working cycle of the charge pump, the first capacitor is charged. During the second half of the working cycle of the charge pump, the second capacitor is charged so that the voltage is two times of the power voltage, after the first capacitor is connected with the power supply in sequence. The boost circuit of the invention does not need an induction and a Schottky diode. All of the capacitors except a voltage-stabilizing capacitor can be integrated into a chip. Therefore, the number of off-chip ancillary components can be reduced. Furthermore, the problem of electromagnetic interference in an inductive boost circuit can be solved.