Step-down Power Supply Circuit Calibration for Low Power Precision
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Solution Overview
Problem
Step-down power supply circuits face a trade-off between manufacturing costs and power consumption due to variations in reference voltage, with high precision requiring high power consumption and low power consumption leading to increased manufacturing costs.
Innovation Solution
A step-down power supply circuit with first and second reference voltage source circuits, a step-down voltage generation circuit, switches, and a calibration control circuit that switches between reference voltages to achieve high precision with low power consumption by identifying and using a calibrated reference voltage source with large variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference voltage generation circuit with small variation is used, then the precision of step-down voltage is improved, but the power consumption of the reference voltage generation circuit increases
Solution Approach 1:
The reference voltage generation function is segmented into two separate circuits: a first reference voltage source circuit that consumes more power but provides small variation (high precision), and a second reference voltage source circuit that consumes less power but provides large variation (low precision). This segmentation allows the system to leverage the strengths of both approaches without being constrained by the trade-off that would exist in a single unified circuit.
Solution Approach 2:
The system dynamically switches between the first and second reference voltage source circuits based on operational requirements. During calibration operations, the first reference voltage source is used to ensure high precision. During normal operations, the second reference voltage source is used to reduce power consumption. This dynamic switching resolves the contradiction by adapting the reference voltage source selection to the current operational context.
2Measurement precision
If calibration is performed using a voltage tester connected to the semiconductor integrated circuit, then the step-down voltage precision is improved, but the manufacturing cost increases
Solution Approach 1:
The semiconductor integrated circuit performs self-calibration using its internal resources (the two reference voltage source circuits, comparison circuit, and calibration control circuit) without requiring external voltage testers or calibration equipment. The calibration process is entirely automated and executed within the circuit itself, eliminating the need for costly external calibration equipment and manual calibration procedures, thereby reducing manufacturing costs while maintaining high precision.
Solution Approach 2:
The calibration process uses a comparison circuit to continuously monitor and compare the step-down voltage against a reference voltage, with the calibration control circuit adjusting the circuit parameters based on the comparison results. This feedback mechanism enables automatic calibration that achieves high precision without requiring external testing equipment, thereby reducing manufacturing costs.
3Productivity
If MOS transistors are miniaturized to achieve higher integration levels, then the integration level is improved, but the operating voltage range becomes narrow
Solution Approach 1:
The invention changes the voltage parameter by introducing a step-down power supply circuit that converts a higher external power supply voltage into a lower, stable step-down voltage suitable for miniaturized MOS transistors. This parameter transformation allows the circuit to operate with narrow voltage ranges required by small transistors while still accepting standard external power supply voltages, thereby enabling higher integration without being constrained by narrow operating voltage requirements.
Data Source
AI summary
A power supply has first and second reference voltage sources; a step-down voltage generator, including a transistor supplied with a first voltage, a resistor string between the transistor and a second voltage, and an op-amp which controls the transistor, and outputting the voltage at a first node among nodes in the resistor string; switches, coupled to the nodes; a comparison circuit, which compares the voltage at a common node the switches coupling in common with the second reference voltage source; and a calibration control circuit, which selects any switch according to a comparison result to calibrate. During calibration, the calibration control circuit couples a second node among the nodes to a non-inverting terminal of the op-amp, and the first reference voltage source to an inverting terminal of the op-amp, and after calibration, couples the common node to the non-inverting terminal, and the second reference voltage source to the inverting terminal.