Power Converter Control Circuit for Linear Output Voltage Compensation
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Solution Overview
Problem
Existing control circuits for power converters suffer from poor regulation effects due to non-linear compensation of output loss, leading to increased errors in secondary side output voltage, as the compensation voltage is not linearly positively changed with the load coupled to the secondary side within frequency variation regions.
Innovation Solution
A control circuit comprising a sampling voltage generator, a time-to-voltage converter, and a compensation signal generator, which generates a compensation signal by utilizing a sampling time signal and corresponding voltage to ensure the compensation voltage is linearly positively changed with the load, thereby improving regulation effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the prior art control circuit uses compensation voltage VCOMP to determine frequency variation curve L for gate control signal, then the output voltage of secondary side can be regulated, but the compensation voltage is not linearly positively changed with load within frequency variation regions A and B, resulting in non-linear compensation and increased output voltage error
Solution Approach 1:
The patent segments the compensation function into two independent parts: (1) a sampling voltage generator that generates sampling voltage VCSS linearly proportional to detection voltage VCS through current mirroring, and (2) a time-to-voltage converter that generates voltage proportional to time interval. This segmentation allows each part to maintain linearity independently, resolving the non-linearity issue when these voltages are combined for compensation.
Solution Approach 2:
The patent introduces a sampling voltage generator as an intermediary component between the detection voltage input and the compensation signal generation. This intermediary converts the detection voltage to a sampling voltage through a linear current mirroring process, ensuring that the compensation signal maintains linear relationship with the load, thereby improving measurement precision.
2Device complexity
If the control circuit uses a single compensation voltage for both output regulation and frequency determination, then circuit complexity is reduced, but the regulation effect deteriorates due to non-linear compensation across different operating regions
Solution Approach 1:
The patent divides the control circuit into distinct functional segments: a sampling voltage generator for linear voltage sampling, a time-to-voltage converter for timing-based compensation, and a compensation signal generator. This segmentation enables precise linear compensation while maintaining manageable circuit complexity through modular design.
Solution Approach 2:
The patent changes the parameter representation by using time interval as an intermediate parameter instead of directly using frequency variation. The time-to-voltage converter transforms the time interval into a voltage that is linearly related to the load, improving regulation precision without significantly increasing circuit complexity.
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 achieves improved regulation of the power converter's output voltage by ensuring the compensation signal is linearly positively correlated with the load, thereby enhancing the compensation effect and reducing errors compared to prior art.
Implementation Method 1
a sampling time signal generator and a voltage generator, wherein the sampling time signal generator is used for generating a sampling time signal according to a first reference current and a second reference current
Implementation Method 2
The voltage generator is coupled to the sampling time signal generator for generating a sampling voltage corresponding to a detection voltage according to the detection voltage and the sampling time signal
Implementation Method 3
The time-to-voltage converter is used for generating a corresponding voltage according to a period of a gate control signal controlling a power switch of a primary side of the power converter and a discharge time of a secondary side of the power converter
Implementation Method 4
The compensation signal generator is coupled to the sampling voltage generator and the time-to-voltage converter for generating a compensation signal compensating the output loss according to the sampling voltage and the corresponding voltage
Data Source
AI summary
A control circuit for compensating output loss of a power converter includes a sampling voltage generator, a time-to-voltage converter, and a compensation signal generator. The sampling voltage generator generates a sampling voltage corresponding to a detection voltage according to a first reference current, a second reference current, and the detection voltage. The time-to-voltage converter generates a corresponding voltage according to a period of a gate control signal controlling a power switch of a primary side of the power converter and a discharge time of a secondary side of the power converter. The compensation signal generator generates a compensation signal compensating the output loss according to the sampling voltage and the corresponding voltage.