POR Reset Circuit Switching for Accurate Quiescent Current Measurement
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Solution Overview
Problem
Existing methods for resetting semiconductor ICs to an initial state after power-on are hindered by the inclusion of power-on reset (POR) circuits, which complicate the measurement of quiescent supply current and require additional terminals, making it difficult to accurately measure the current without dedicated terminals, especially under cost and functional limitations.
Innovation Solution
A reset device comprising a POR circuit, first and second switches, and a control circuit that manages the supply voltage and signal lines to isolate the POR circuit's current from the main circuit part, allowing for accurate quiescent supply current measurement by switching between normal and test modes without a dedicated terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a POR circuit is provided in the semiconductor IC to reset the circuit part to an initial state, then the circuit part can be reliably reset to a predetermined initial state, but the measurement of quiescent supply current becomes complicated and requires additional terminals
Solution Approach 1:
The power supply path is segmented into two separate paths: a first power supply line for the circuit part and a second power supply line for the POR circuit. This segmentation allows independent control and measurement of currents, enabling quiescent supply current measurement without requiring additional terminals beyond the existing power supply terminals.
Solution Approach 2:
Switches are introduced as intermediary elements to control the connection between power supply lines and the POR circuit. These switches act as mediators that can isolate or connect the POR circuit to specific power supply lines based on operational mode, enabling flexible current measurement without adding external measurement terminals.
2Reliability
If the POR circuit is always connected to the power supply line, then the circuit part can be reliably reset, but the quiescent supply current measurement includes POR circuit current making accurate measurement difficult
Solution Approach 1:
The power supply configuration is made dynamic through switches that can change the connection state between the POR circuit and power supply lines based on operational mode. In normal operation mode, the POR circuit is connected to ensure reset functionality. In measurement mode, the switches reconfigure to isolate the POR circuit current from the measurement path, enabling accurate quiescent current measurement.
Solution Approach 2:
Different parts of the power supply system are given different functional qualities: the first power supply line is optimized for circuit part power supply, while the second power supply line is specifically for POR circuit operation. This local differentiation allows the measurement system to selectively measure only the circuit part current by controlling which power supply line is active.
3Measurement precision
If additional terminals are added to the semiconductor IC for quiescent supply current measurement, then accurate measurement can be achieved, but the device complexity and cost increase
Solution Approach 1:
The existing power supply terminals are made multi-functional: they serve both as power supply terminals during normal operation and as measurement terminals during quiescent current measurement. This universality eliminates the need for dedicated measurement terminals, reducing device complexity and cost while maintaining measurement accuracy through internal switch-based isolation.
Data Source
AI summary
A reset device includes a power-on reset (POR) circuit configured to output a reset signal to reset a circuit part to an initial state when supply voltage is lower than a threshold level, a first switch provided in a path connecting a first line to supply the supply voltage to the circuit part and a second line to supply the supply voltage to the POR circuit, a second switch provided in a path connecting a signal line of the circuit part and the second line, and a control circuit configured to turn on the first switch and turn off the second switch in a normal mode, and to turn off the first switch and turn on the second switch in a test mode. The control circuit turns on the first switch and turns off the second switch in response to the reset signal being output from the POR circuit.