Chip Ground Detection via EPAD Resistance Measurement
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Solution Overview
Problem
Existing methods for detecting poor connections between the exposed pad (EPAD) of an application-specific integrated circuit chip and the PCB grounding copper plate, such as X-ray inspection, are inadequate for field applications, leading to potential safety risks due to insufficient ignition currents and failed airbag deployment.
Innovation Solution
A chip ground detection device comprising a current source, switching units, and a voltage monitoring unit, which measures the ground resistance of the exposed pad by comparing voltages with and without a diagnostic current, using switching units to control the flow of current and determine resistance based on the EPAD's grounding condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If X-ray inspection is used to detect EPAD GND solder connection, then manufacturing precision can be improved, but device complexity and cost increase
Solution Approach 1:
The chip's own internal circuitry is used to perform the ground detection function. The detection current is generated within the chip, and the voltage measurement is performed by the chip's own monitoring unit, eliminating the need for external complex detection equipment like X-ray inspection systems.
Solution Approach 2:
The ground detection function is extracted as a separate operational mode within the chip. By using switching units to isolate the detection current path from the normal operating current, the detection function can be performed independently without affecting the main chip functionality, and without requiring external detection equipment.
2Measurement precision
If X-ray inspection is used for ground detection, then measurement capability is improved, but it cannot cover field application faults
Solution Approach 1:
The ground detection circuit is built into the chip and activated during field operation. This preliminary preparation of the detection capability within the chip allows it to detect ground connection issues in real-time during field application, not just during manufacturing inspection.
Solution Approach 2:
The detection circuit serves multiple purposes: it can detect ground connection issues both during manufacturing and during field operation. The same hardware infrastructure (current source, switching units, voltage monitoring) handles both manufacturing inspection and field diagnostics, making the system universally applicable.
3Reliability
If the exposed pad connection is poor, then grounding reliability deteriorates, but no timely detection mechanism exists
Solution Approach 1:
The voltage monitoring unit continuously monitors the voltage at the exposed pad and compares it against expected values. When a ground connection fault occurs, the monitoring detects the abnormal voltage condition and triggers a fault indication, providing real-time feedback about grounding status without requiring external inspection equipment.
Solution Approach 2:
The ground detection capability is continuously available during chip operation. The switching units can activate the detection current at any time to perform ground resistance measurement, ensuring continuous monitoring of grounding reliability rather than relying on periodic external inspections.
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
Enables timely detection of ground faults in the chip, ensuring reliable airbag deployment by accurately measuring ground resistance and ignition resistor resistance, thereby preventing safety hazards.
Implementation Method 1
determines a ground resistance for the exposed pad EPAD based on the first voltage V1 and the second voltage V2
Data Source
AI summary
A chip ground detection device includes (i) a current source, (ii) a switching device including one or more switching units, (iii) a voltage monitoring unit coupled to an exposed pad of a chip via the one or more switching units, and (iv) a control unit for controlling the one or more switching units and configured to close the one or more switching units when the current source is operating, such that the voltage monitoring unit obtains a first voltage V1 on the exposed pad; is configured to close the one or more switching units when the current source is not operating, such that the voltage monitoring unit obtains a second voltage V2 on the exposed pad; and determines a ground resistance for the exposed pad based on the first voltage V1 and the second voltage V2 . An application-specific integrated circuit chip, a method of chip ground detection, and a computer program product are also disclosed.