Shared-Capacitor High-Voltage Sensing for Display Driver ICs
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Solution Overview
Problem
Existing high voltage sensing circuits in semiconductor integrated circuits face challenges in efficiently sensing high voltages while minimizing power consumption and chip area, often resulting in increased complexity and potential sensing errors due to the need for multiple capacitors and complex switch structures.
Innovation Solution
A high voltage sensing circuit design that incorporates a shared feedback capacitor across multiple channels, allowing for efficient sensing of high voltages with reduced capacitor count and area usage, while also incorporating a switch structure to prevent damage to low-voltage holding and scaling units, thereby enhancing reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple capacitors are used for each channel to sense high voltages, then sensing accuracy is improved, but chip area and device complexity increase
Solution Approach 1:
The patent merges the feedback capacitors across multiple channels into a single shared capacitor. The switching circuit selectively connects different channels to the same feedback capacitor at different time intervals, eliminating the need for separate capacitors for each channel while maintaining sensing accuracy through sequential measurement.
Solution Approach 2:
The feedback capacitor is designed to serve multiple functions across different channels. A single feedback capacitor performs the sensing function for all channels by being selectively connected to different channels through the switching circuit, making the component universal rather than channel-specific.
2Adaptability or versatility
If multiple capacitors and complex switch structures are used for high voltage sensing, then sensing coverage is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple channel sensing functions into a single feedback capacitor infrastructure. The switching circuit integrates control for multiple channels, reducing the overall number of discrete components while maintaining the ability to sense across all channels.
Solution Approach 2:
The sensing operation uses periodic switching between channels, where each channel is sequentially connected to the shared feedback capacitor at specific time intervals. This periodic multiplexing approach enables multi-channel coverage without requiring simultaneous dedicated components for each channel.
3Use of energy by moving object
If high voltage sensing is performed without protection structures, then power consumption is reduced, but reliability decreases due to potential damage to low-voltage units
Solution Approach 1:
The switching circuit acts as an intermediary between the high voltage sensing input and the low-voltage feedback capacitor and holding unit. This intermediary structure isolates the sensitive low-voltage components from direct exposure to high voltage while enabling controlled signal transfer, thus protecting the low-voltage units without requiring additional protection components.
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 design enables efficient sensing of high voltages with improved accuracy and reliability by minimizing mismatch errors and performing scaling and holding operations simultaneously, while maintaining low power consumption and compact chip area.
Implementation Method 1
The feedback capacitor is connected between an input terminal and an output terminal of the amplifier, and shared by the plurality of channels. The amplifier and the feedback capacitor are configured such that each of the plurality of sampled input voltages is sequentially scaled to the respective one of the plurality of sensing voltages by the amplifier and the feedback capacitor.
Data Source
AI summary
A high voltage sensing circuit included in a display driver integrated circuit includes a plurality of channels, a plurality of sampling capacitors, an amplifier and a feedback capacitor. The plurality of channels receives a plurality of input voltages. The plurality of sampling capacitors are connected to the plurality of channels, respectively, to simultaneously sample the plurality of input voltages. The amplifier is configured to sequentially receive each of a plurality of sampled input voltages to sequentially generate a respective plurality of sensing voltages. The feedback capacitor is connected between an input terminal and an output terminal of the amplifier, and is shared by the plurality of channels. The amplifier and the feedback capacitor are configured such that each of the plurality of sampled input voltages is sequentially scaled to the respective one of the plurality of sensing voltages by the amplifier and the feedback capacitor.