Converter Dead-Time Control for Low-Loss Power Adapters
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Solution Overview
Problem
The challenge is to reduce energy loss in power adapters due to increased power density, which leads to higher heat generation and limited natural heat dissipation, necessitating effective energy loss reduction strategies.
Innovation Solution
A converter design incorporating a DC power supply, primary and auxiliary power transistors, a capacitor, and a transformer, with a control circuit that regulates the target voltage to a preset threshold, allowing the primary power transistor to turn on at minimal energy loss by optimizing the dead time and turn-on duration of the auxiliary power transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power density is improved to meet miniaturization and fast charging requirements, then charging speed and volume efficiency are improved, but energy loss and heat generation increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the dead time between switching of the auxiliary and primary power transistors based on the excitation current state. By changing the timing parameters of the switching circuit, the patent optimizes the operating conditions to reduce energy loss while maintaining high power density, directly addressing the contradiction between improved power density and reduced energy loss
2Power
If power density is improved, then output power per unit volume increases, but heat dissipation capacity becomes insufficient
Solution Approach 1:
The patent converts the harmful effect of excitation current in the transformer into a beneficial control parameter. By detecting the excitation current state and using it to regulate the dead time, the patent transforms what would normally be a source of energy loss into a useful signal for optimizing system performance, thereby reducing heat generation while maintaining high output power density
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
This approach significantly reduces energy loss in the power adapter by ensuring the primary power transistor operates at the lowest possible voltage, thereby minimizing energy consumption and heat generation.
Implementation Method 1
a function of the first capacitor is to resonate with an inductor in the transformer, a parasitic capacitor of the primary power transistor, and a parasitic capacitor of the auxiliary power transistor after the auxiliary power transistor is turned off
Implementation Method 2
a transformer, and/or a control circuit. The first capacitor is connected in series to the transformer to form a series circuit
Implementation Method 3
If the power density is improved, a current or voltage increases. In this case, more energy is used to generate heat
Data Source
AI summary
This application discloses a converter and a power adapter, to reduce an energy loss of the power adapter. The converter includes: a DC power supply, a primary power transistor, an auxiliary power transistor, a first capacitor, a transformer, and a control circuit. The first capacitor is connected in series to the transformer to form a series circuit, the series circuit is connected in parallel to a first terminal and a second terminal of the auxiliary power transistor. The control circuit is configured to: when an excitation current in the transformer is in a continuous state, regulate a target voltage to a preset voltage threshold, and control the primary power transistor to be turned on when first dead time ends, where the target voltage is a voltage between the first terminal of the primary power transistor and the ground.