Power Supply IC Terminal Merging for PFC Circuit Design
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Solution Overview
Problem
Integrated circuits for power factor correction circuits face challenges in managing multiple current and voltage detections, leading to an increase in the number of terminals required, which complicates the design and functionality.
Innovation Solution
An integrated circuit design that includes a transformer with a primary and secondary winding, a transistor to control the inductor current, and detection circuits to determine AC voltage amplitude based on secondary winding voltage, allowing the circuit to drive the transistor based on detection results and output voltage, thereby reducing the number of terminals needed for multiple detection targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple currents and voltages are detected separately using multiple terminals, then detection accuracy is improved, but the number of terminals increases
Solution Approach 1:
The patent combines multiple detection functions (inductor current detection and AC voltage amplitude detection) into a single terminal. The terminal receives a composite signal that contains information about both the inductor current and the AC voltage amplitude, allowing the integrated circuit to detect multiple parameters through one terminal rather than requiring separate terminals for each parameter.
Solution Approach 2:
The terminal is designed to serve multiple functions simultaneously. It acts as both a current sensing terminal and a voltage detection terminal, receiving signals that enable the circuit to determine both the inductor current status and the AC voltage amplitude level, thereby making a single terminal universal for multiple detection purposes.
2Device complexity
If the number of terminals is reduced, then device complexity is decreased, but detection capability may be compromised
Solution Approach 1:
The patent introduces an intermediary mechanism where the terminal receives a composite signal that acts as a mediator between the multiple detection targets (inductor current and AC voltage) and the internal detection circuits. This composite signal contains encoded information about multiple parameters, allowing the terminal to intermediate multiple detection functions without requiring multiple separate terminals.
Solution Approach 2:
The detection circuits internally transform the received composite signal into different parameter interpretations. By changing the detection parameters and signal processing methods within the circuit, the system can extract multiple pieces of information (current status, voltage amplitude) from a single terminal input, maintaining detection versatility while reducing terminal count.
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
The solution enables efficient power factor correction with reduced terminal count, improving power factor and reducing switching loss by accurately determining AC voltage amplitude and controlling the transistor accordingly.
Implementation Method 1
a transformer including a primary winding to which a rectified voltage obtained by rectifying an alternating-current (AC) voltage is applied, and a secondary winding configured to induce a voltage having a polarity opposite to a polarity of a voltage generated in the primary winding
Data Source
AI summary
An integrated circuit for a power supply circuit that includes a transformer and a transistor controlling an inductor current flowing through a primary winding of the transformer. The integrated circuit includes a terminal receiving a voltage corresponding to the voltage of a secondary winding of the transformer when the transistor is in an off-state, a first detection circuit detecting that the inductor current is smaller than a first current value, and a determination circuit determining whether an AC voltage applied to the primary winding of the transformer is a first or second AC voltage, both based on the received voltage in the off-state of the transistor. The integrated circuit is configured to drive the transistor in response to a detection result of the first detection circuit, a determination result of the determination circuit, and an output voltage of the power supply circuit generated from the AC voltage.