Single-Pin Resistor Readout Circuit for Fast Switch Speed Programming
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Solution Overview
Problem
Existing electrical circuits face challenges in accurately and efficiently reading out resistor values with limited pins, particularly in semiconductor chips, while minimizing noise interference and ensuring fast measurement during power transistor startup.
Innovation Solution
A semiconductor chip-based circuit that uses a single pin to measure two external resistors by mirroring currents internally and applying error correction to account for component currents, utilizing analog-to-digital converters and noise cancellation techniques to ensure accurate resistance determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pin is used to read out resistances of two resistors, then the number of pins required is reduced, but the measurement accuracy deteriorates due to current interference between resistors
Solution Approach 1:
The patent applies periodic action by sequentially switching between different voltage levels (first voltage and second voltage) applied to the second pin. During the first voltage phase, the resistance of the first external resistor is measured. During the second voltage phase, the resistance of the second external resistor is measured. This time-sequential periodic measurement eliminates current interference between resistors while using only a single pin, thus resolving the contradiction between pin reduction and measurement accuracy.
2Measurement precision
If resistance measurement is performed during startup before power transistor turns on, then noise interference is minimized, but the measurement time window is limited
Solution Approach 1:
The patent applies preliminary action by performing the resistance measurements during the startup phase before the power transistor is turned on. This timing ensures that noise interference from the power transistor is minimized, allowing for accurate measurements. The multi-phase voltage switching is completed within this limited time window, establishing the resistor values before normal operation begins.
3Measurement precision
If multiple voltage levels are applied sequentially to measure different resistors, then accurate resistance determination is achieved, but the measurement process becomes more complex
Solution Approach 1:
The patent applies universality by designing a single pin that serves multiple functions: it is used to measure both the first external resistor and the second external resistor through sequential voltage switching. The same pin and measurement circuitry are reused for both resistance measurements, eliminating the need for separate measurement paths and reducing overall system complexity despite the multi-phase measurement process.
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 precise and rapid measurement of resistor values with minimal pin usage and reduced noise interference, facilitating efficient programming of turn-on and turn-off speeds for integrated power switches.
Implementation Method 1
a first current flowing from the second pin through the first external resistor to the reference potential due to the first voltage is mirrored internally to determine, using an analog to digital converter, a first digital resistance value representing a resistance of the first external resistor
Data Source
AI summary
An apparatus as discussed herein includes: a first circuit node coupling a first resistor and a second resistor in series between an input voltage source and a reference voltage source; current mirror circuitry coupled to the first circuit node, the current mirror circuitry operative to: i) produce a first mirror current based a first current conveyed through the first resistor, and ii) produce a second mirror current based on a second current conveyed through the second resistor; and measurement circuitry operative to determine resistances of the first resistor and the second resistor via various techniques.