Bandgap Reference Voltage Trimming Through Package Pins
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for measuring internal bandgap reference voltages in packaged electronic devices, such as isolated amplifiers, face challenges due to measurement errors caused by large series resistance and leakage currents, which can lead to inaccurate temperature gain drift and increased temperature variation.
Innovation Solution
A method involving an internal switch and analog front end that connects to a reference ground of the internal voltage source, allowing for accurate measurement and trimming of internal bandgap reference voltages by using a zero detector output signal to adjust and match the voltage level, thereby minimizing temperature variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the assigned package pin is used to measure internal bandgap reference voltage, then the measurement can be performed through existing package pins, but the large series resistance between the package pin and the signal causes prohibitive measurement errors when small leakage current flows
Solution Approach 1:
The patent applies preliminary action by performing a calibration measurement before the actual voltage measurement. The internal switch is first connected to a known reference voltage (e.g., ground or a precise reference), and the system characterizes the offset and gain errors introduced by the high-impedance path. This preliminary characterization allows the system to compensate for the series resistance and leakage current effects during subsequent measurements, thereby achieving accurate voltage measurements despite the harmful high-impedance conditions.
Solution Approach 2:
The patent employs feedback by using the measured output signal and the known reference voltage to calculate correction factors that are applied to subsequent measurements. The system continuously monitors the actual voltage at the package pin and adjusts for deviations caused by leakage current and series resistance. This feedback mechanism enables the system to maintain measurement accuracy despite the presence of harmful electrical effects in the high-impedance path.
2Ease of operation
If large input resistances are used in the analog front end to attenuate input signals, then the input signal attenuation is improved, but measurement errors increase when small leakage current flows through the package pin
Solution Approach 1:
The patent applies preliminary action by performing a calibration measurement before the actual voltage measurement. The internal switch is first connected to a known reference voltage (e.g., ground or a precise reference), and the system characterizes the offset and gain errors introduced by the high-impedance path. This preliminary characterization allows the system to compensate for the series resistance and leakage current effects during subsequent measurements, thereby achieving accurate voltage measurements despite the harmful high-impedance conditions.
Solution Approach 2:
The patent employs feedback by using the measured output signal and the known reference voltage to calculate correction factors that are applied to subsequent measurements. The system continuously monitors the actual voltage at the package pin and adjusts for deviations caused by leakage current and series resistance. This feedback mechanism enables the system to maintain measurement accuracy despite the presence of harmful electrical effects in the high-impedance path.
3Stability of the object's composition
If bandgap trim is performed to reduce temperature variation, then the temperature gain drift is improved, but errors in the bandgap trimming process negatively impact the temperature gain drift
Solution Approach 1:
The patent applies preliminary action by performing a calibration measurement before the actual voltage measurement. The internal switch is first connected to a known reference voltage (e.g., ground or a precise reference), and the system characterizes the offset and gain errors introduced by the high-impedance path. This preliminary characterization allows the system to compensate for the series resistance and leakage current effects during subsequent measurements, thereby achieving accurate voltage measurements despite the harmful high-impedance conditions.
Solution Approach 2:
The patent employs feedback by using the measured output signal and the known reference voltage to calculate correction factors that are applied to subsequent measurements. The system continuously monitors the actual voltage at the package pin and adjusts for deviations caused by leakage current and series resistance. This feedback mechanism enables the system to maintain measurement accuracy despite the presence of harmful electrical effects in the high-impedance path.
Data Source
AI summary
A method comprising activating an internal switch within a packaged electronic device to connect to a reference ground of an internal voltage source to a first input of an analog front end, receiving an external ground potential voltage at a first package pin of the packaged electronic device, generating a zero detector output signal for the packaged electronic device at a second package pin, activating the internal switch to connect the first input of the analog front end to the internal voltage source, receiving a second voltage level at the first package pin that generates a second output signal that matches the zero detector output signal, and receiving trim instructions to trim an internal voltage generated by the internal voltage source to a voltage level that is closer to a target voltage level.