Boost PFC Shared-Pin Sensing for Current and Temperature Control
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Solution Overview
Problem
Conventional boost power factor correction circuits require a dedicated pin for temperature sensing, increasing the size and cost of the integrated circuit.
Innovation Solution
A boost power factor correction circuit with a shared pin that integrates current and temperature sensing, allowing the integrated circuit to operate the first switch based on a multipurpose sensing signal, which is related to current sensing when the switch is ON and temperature sensing when it is OFF, thereby reducing circuit size and cost while providing over temperature protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated pin is used for temperature sensing, then temperature sensing accuracy is improved, but integrated circuit size and manufacturing cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single pin to serve dual purposes: current sensing during the switch ON period and temperature sensing during the switch OFF period. The sensing circuit reconfigures its function based on the switching state, allowing the same hardware resource to perform multiple measurement tasks without requiring separate dedicated pins for each function.
Solution Approach 2:
The patent implements periodic action by alternating between current sensing and temperature sensing based on the switching cycle. During each switching period, the pin alternates between measuring current when the switch is ON and measuring temperature when the switch is OFF, utilizing the periodic nature of the power conversion process to sequentially perform different sensing functions.
2Reliability
If a dedicated pin is used for temperature sensing, then temperature sensing capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent reduces manufacturing cost by designing a universal sensing pin that performs both current and temperature sensing functions. This eliminates the need for additional pins and associated external components that would be required for dedicated temperature sensing, thereby simplifying the overall circuit design and reducing manufacturing expenses while maintaining over-temperature protection capability.
Solution Approach 2:
The patent merges the current sensing and temperature sensing functions into a single integrated circuit pin and sensing pathway. By combining these functions that were previously separate into a unified multi-functional pin, the patent reduces component count and simplifies the circuit architecture, leading to lower manufacturing costs.
3Measurement precision
If multiple separate pins are used for current and temperature sensing, then sensing accuracy is improved, but the number of pins and circuit complexity increase
Solution Approach 1:
The patent employs a universal pin design that can accurately sense both current and temperature parameters through temporal multiplexing. The sensing circuit maintains measurement accuracy by switching between current sensing mode and temperature sensing mode according to the power switch state, achieving dual-functionality without compromising sensing precision.
Solution Approach 2:
The patent introduces dynamic functionality to the sensing pin, allowing it to change its sensing mode dynamically based on the switching state. The pin transitions between sensing current during the ON period and sensing temperature during the OFF period, making the sensing system adaptive and flexible rather than static and dedicated to a single function.
Data Source
AI summary
A boost power factor correction circuit includes: a switch and an inductor coupled to each other; a current sensing device generating a current sensing signal according to a current flowing through the switch; a temperature sensing device coupled to the inductor to generate a temperature sensing signal; and a conversion control circuit operating the switch. The conversion control circuit is an integrated circuit and includes: a shared pin coupled to the temperature sensing device and the current sensing device; and a current sensing circuit and a temperature sensing circuit which sense a multipurpose sensing signal through the shared pin. The multipurpose sensing signal is related to the current sensing signal when the switch is ON and related to the temperature sensing signal when the switch is OFF. The temperature sensing signal is related to an input voltage, an output voltage and an electrical parameter of the temperature sensing device.