Detection Circuit for Integrated Power Source Capacitor Drift
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Solution Overview
Problem
Existing methods for detecting the open state or parameter drift of an external capacitor in integrated circuits are either unreliable or inconvenient, particularly in automotive applications, as they often require high currents that can negatively impact chip performance.
Innovation Solution
A detection circuit is introduced that includes a second resistor and capacitor connected in series between the power source terminal and the reference electric potential terminal, with a simulated power source terminal and comparator to measure voltage differences, allowing for the detection of drift or open circuits without additional external components, and is integrated into the integrated circuit chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If AC current load is added to measure open state between source pin and external capacitor, then measurement capability is improved, but chip performance deteriorates due to high currents and AC ripple
Solution Approach 1:
The patent creates an internal RC circuit that copies the external RC circuit's time constant characteristics. By measuring the voltage response of this internal copy circuit, the system can detect external capacitor status without directly applying measurement currents to the external capacitor, thus avoiding AC ripple and high current impacts on chip performance
Solution Approach 2:
The patent introduces an internal RC circuit as an intermediary measurement system. This internal circuit acts as a mediator that translates the external capacitor's state into measurable voltage changes without requiring direct high-current injection into the external capacitor, thereby eliminating the harmful AC ripple effect
2Difficulty of detecting and measuring
If external components are added for detection, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the detection function with the existing internal RC circuit structures of the integrated circuit. The second resistor and second capacitor are integrated into the chip's internal circuitry rather than being external components, achieving accurate measurement while maintaining simple device structure and avoiding additional external components
Solution Approach 2:
The internal RC circuit serves multiple functions: it acts as both the detection measurement circuit and mimics the external RC time constant behavior. This multi-functionality eliminates the need for separate dedicated detection components, reducing overall device complexity while maintaining measurement accuracy
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 enables reliable detection of external capacitor states without adding external components, offering easy integration and low cost, while maintaining chip performance by matching the internal RC circuit's time constant with the external RC circuit, thus avoiding the need for direct current measurement.
Implementation Method 1
a comparator that is coupled to the second power source terminal and the simulated power source terminal and suitable for measuring a voltage difference between a filtered power source voltage of the second power source terminal and a simulated power source voltage of the simulated power source terminal
Implementation Method 2
a capacitor C is connected between the filtered source pin 112 and the ground pin 111... the capacitor C can form a filter circuit to filter the signal
Data Source
AI summary
A detection circuit and an integrated circuit. The detection circuit is used for detecting the drift or an open circuit of a first capacitor (C1) on a filtered second power source terminal (220), and the second power source terminal (220) is suitable for acquiring a power source voltage from an unfiltered first power source terminal (210) by means of a first resistor (R1), and is suitable for being coupled to a reference electric potential terminal (230) by means of the first capacitor (C1). The detection circuit comprises a second resistor (R2) and a second capacitor (C2) that are connected in series and coupled between the first power source terminal (210) and the reference electric potential terminal (230), wherein the second resistor (R2) and the second capacitor (C2) have the same time constant as the first resistor (R1) and the first capacitor (C1).