Display Driver Sensing Circuit Without ADC Scaling Stage
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Solution Overview
Problem
In OLED display panels, the threshold voltage signal needs to be scaled down from an analog voltage range to a low-voltage range for conversion by an ADC, requiring additional circuitry and area, especially when considering the large number of pixel circuits.
Innovation Solution
A sensing circuit that uses high voltage components to directly amplify and transform analog voltage signals into differential output signals, eliminating the need for a scaling circuit by employing a sample and hold circuit and a gain amplifier to generate pairs of differential input and output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scaling circuit is used to transform the analog voltage signal to a low-voltage range for ADC conversion, then the ADC can accurately convert the threshold voltage signal, but the circuit area and hardware complexity increase significantly
Solution Approach 1:
The patent changes the voltage level parameters by using high voltage components throughout the signal path, from the sample and hold circuit through the gain amplifier to the ADC. This allows the ADC to directly convert high-voltage differential signals without requiring a scaling circuit, thereby maintaining measurement precision while significantly reducing circuit area
Solution Approach 2:
Instead of the conventional approach of scaling down the voltage signal before ADC conversion, this patent inverts the approach by using an ADC that can directly handle high-voltage differential signals. This inversion eliminates the need for the scaling circuit and its associated area overhead
2Adaptability or versatility
If a scaling circuit is added to transform the analog voltage signal, then the voltage range compatibility is improved, but the device complexity and hardware cost increase
Solution Approach 1:
The gain amplifier in this patent serves multiple functions: it amplifies the differential signal, maintains high-voltage level compatibility, and prepares the signal for direct ADC conversion. This multi-functionality eliminates the need for separate scaling circuits, thereby reducing device complexity while maintaining voltage range compatibility
Solution Approach 2:
The patent changes the operating voltage parameters of the entire sensing circuit by using high voltage components, which improves voltage range compatibility across the signal path and eliminates the need for additional scaling circuitry, thereby reducing overall device complexity
Data Source
AI summary
A sensing circuit is provided. The sensing circuit includes a sample and hold circuit and a gain amplifier. The sample and hold circuit includes a first charging path and a second charging path. The first charging path selectively generates a first charging potential between a first sensing terminal and a first reference terminal according to the analog voltage signal and a reference voltage. The second charging path selectively conducts the reference voltage to a second sensing terminal. A pair of differential input signals are generated at the first sensing terminal and the second sensing terminal. The first charging path and the second charging path are implemented by high voltage components. The gain amplifier receives the pair of differential input signals through a first and a second input terminals and generates a pair of differential output signals at a first and a second output terminals.