Power Converter Control Device Dynamic Over Power Protection
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Solution Overview
Problem
Conventional over power protection methods for switching power supplies with variable output voltages either set a fixed protection point or lack flexibility, leading to inefficiencies and increased power consumption, particularly when using sampling resistors on the secondary side.
Innovation Solution
A control device for a power converter that includes a first control unit to detect output voltage and generate control signals, a variable resistor unit to adjust resistance values based on these signals, and a second control unit to manage the switch unit, allowing for dynamic over power protection settings tailored to different output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If over current protection on secondary side is applied to satisfy respective over power protection points, then adaptability is improved, but device complexity and power consumption increase due to sampling resistors
Solution Approach 1:
The patent introduces a variable resistance unit as an intermediary component that translates the control signal (first control signal) into a variable reference voltage. This variable reference voltage serves as a mediator between the control logic and the over-power protection comparison operation, enabling different protection points without direct secondary side current sensing.
Solution Approach 2:
The patent replaces the mechanical/electrical sampling resistor method (secondary side current measurement) with an electrical field-based method (variable reference voltage generation through resistance control). This substitution eliminates the need for physical sampling resistors on the secondary side while achieving the same protection functionality.
2Measurement precision
If sampling resistor is applied for over current protection, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent substitutes the power-consuming sampling resistor method with a control-signal-driven variable reference voltage method. The over-power detection is achieved by comparing the fixed feedback voltage with the variable reference voltage, eliminating the need for continuous current sensing through resistors and thus reducing steady-state power consumption.
Solution Approach 2:
The system uses its own control signal (first control signal corresponding to output voltage) to automatically adjust the reference voltage for protection. This self-service mechanism eliminates the need for external sensing components and their associated power consumption, as the control signal itself drives the protection threshold adjustment.
3Use of energy by moving object
If traditional over power protection on primary side is applied, then power consumption is reduced, but adaptability deteriorates as protection point remains fixed
Solution Approach 1:
The patent transforms the static fixed protection point into a dynamic variable protection point by introducing a variable resistance unit. The resistance value of this unit changes according to the first control signal (which corresponds to output voltage), making the reference voltage and thus the protection point dynamically adjustable without increasing power consumption.
Solution Approach 2:
The patent changes the key parameter of the protection threshold from a fixed voltage value to a variable reference voltage whose magnitude is determined by the first control signal. This parameter change enables the protection point to vary with output voltage conditions, achieving adaptability while maintaining low power consumption characteristics.
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
Enables flexible and efficient over power protection by adjusting resistance values based on detected output voltages, optimizing power supply performance across varying voltage conditions without excessive power consumption.
Implementation Method 1
an auxiliary winding, which is configured so that a second terminal thereof is connected to a first ground terminal, and a first terminal of the auxiliary winding, a second terminal of the primary winding and the first terminal of the second winding are dotted terminals
Data Source
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AI summary
The disclosure relates to a control device, a control method of a power converter and a switching power supply using the control device. The control device of the power converter includes: a first control unit, which is coupled to the power converter to detect an output voltage of the power converter and is configured to generate a first control signal based on the output voltage; a variable resistor unit, which is connected to an output terminal of the first control unit to receive the first control signal and is configured to generate a resistance value based on the first control signal; and a second control unit, which is connected to the variable resistor unit and is configured to output a second control signal in order to control operations of a switch unit of the power converter.