Synchronous Buck Converter Current Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power converters experience significant conduction losses due to the voltage drop across diodes, which reduces operational efficiency, especially as input voltage increases.
Innovation Solution
A synchronous buck converter topology is employed, replacing conventional diodes with voltage-controlled switches (MOSFETs) that alternate between storage and discharge modes, utilizing current monitoring circuits to manage the switches and minimize voltage drop, thereby reducing conduction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional diodes are used in power converters, then the circuit structure is simple, but conduction losses increase due to voltage drop
Solution Approach 1:
The patent changes the electrical parameters by replacing diodes with MOSFET switches that have much lower on-resistance. This parameter change allows the circuit to maintain simplicity while dramatically reducing conduction losses, as MOSFETs can be controlled to have lower resistance than diodes during their conducting state.
Solution Approach 2:
The patent substitutes the passive diode component with an active MOSFET switch that can be controlled by voltage signals. This substitution enables the circuit to dynamically control current flow and minimize voltage drop, thereby reducing conduction losses while maintaining structural simplicity through integrated control.
2Power
If input voltage increases, then power conversion capability improves, but conduction losses increase due to diode voltage drop
Solution Approach 1:
The patent introduces dynamic control by using MOSFET switches that can be turned on and off based on operating conditions. This dynamic behavior allows the circuit to adapt to varying input voltages and maintain optimal conduction characteristics, reducing losses even as power conversion capability increases with higher input voltages.
Solution Approach 2:
The patent changes the electrical parameters by using MOSFETs with controllable on-resistance that can be optimized for different voltage levels. This allows the power converter to maintain high efficiency across a wide range of input voltages, unlike diode-based circuits where losses increase linearly with voltage.
3Device complexity
If diodes are used for current rectification, then the circuit is simple, but voltage stress on components increases
Solution Approach 1:
The patent substitutes diodes with MOSFET switches that can be controlled to share voltage stress during switching transitions. This substitution maintains circuit simplicity while distributing voltage stress across multiple components and time periods, reducing peak voltage stress on individual elements.
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 configuration allows the buck converter to operate efficiently with higher input voltages without the conduction losses associated with diodes, maintaining efficiency and reducing voltage stress, thus enhancing overall power conversion efficiency.
Implementation Method 1
A first MOSFET (e.g., high-side MOSFET) is connected in series with a tank inductor forming a first current loop
Implementation Method 2
A second MOSFET (e.g., a low-side MOSFET) is connected in series with the tank inductor forming a second current loop
Implementation Method 3
current monitoring circuitry that selectively switches the state of the first voltage-controlled switch and the state of the second voltage-controlled switch based on a measurement of current through the tank inductor
Data Source
AI summary
A power converter includes a buck converter with a low-side switch. During a discharge mode, current passes through the low-side switch to form a current loop. The low-side switch is typically closed synchronously with the opening of a high-side switch coupled to an input voltage level to the buck converter. The power converter also includes a high-side controller and a low-side controller, which together are configured to adjust the timing of the operation mode of the high-side controller between a storage mode and the discharge mode.