Buck Converter | PartQuest™ Explore

Application Area

Designer19

Member for

11 years 8 months

1,842

designs

10

groups

Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

TDFS Loop Stability for Buck DC to DC Converter - State Average

Designer19

Member for

11 years 8 months

1,842

designs

10

groups

Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

Description

This design uses both TDFS and standard AC Analysis methods to assess the stability of a closed-loop system. The design is the "Buck DC to DC Converter", using a state-average model for the modulator function. The use of state-average models supports AC Analysis, but TDFS (Time Domain Frequency Sweep) is also used to show the equivalency of the methods. Note that the TDFS approach can be used for systems that do not support AC Analysis, such as switching circuits or systems that contain sampling or digital control aspects. This particular example is directly comparable to the design "TDFS Loop Stability for Buck DC to DC Converter - Switching". In that design, the TDFS method is used to measure the open loop transfer function of an operational switching circuit.Note that the approach used to characterize the loop stability, by injecting a small sinusoidal stimulus signal in series with the loop and then measuring the complex ratio of the ground referenced return signal to the injected signal, is described in:D. Venable, “Testing Power Sources for Stability”, Venable technical paper #1, Venable Industries

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Buck DC to DC Converter - Switching

Designer19

Member for

11 years 8 months

1,842

designs

10

groups

Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

Description

This design is a detailed circuit implementation of the more abstract "state-average" buck converter model shown in the companion design example: “Buck DC to DC Converter vs. Linear Regulator”. This example includes the low-pass voltage sense circuit, an op-amp implementation of the difference amplifier and the lead-lag compensators, as well as PWM switching control of a power MOSFET. Simulation results for the line and load transients, ripple rejection and the power consumption are very similar to the results from the abstract model.This design uses a number of "datasheet characterized" components, including the power MOSFET (MCH6337), freewheel diode (NRVBA130LT3G) and op-amps (NCV20071), as well as the passive inductor (MSS1583-105KE_) and capacitor (PEG127KA3110Q) of the power stage . The parameter values of these devices were entered directly from the datasheet for the corresponding part, including the "Maximum Ratings" information.While the simulation time for this switching circuit is significantly longer than for the abstract model, more detailed information about the circuit’s signals and components is available. This includes the component stress levels, which are monitored within all the "datasheet" models. For example, the stress indicator for the power inductor shows that the maximum RMS current level is exceeded under this simulated operating condition (i.e. stress_ratio_current_rms &gt; 1.0).The companion design, "TDFS Loop Stability for Buck DC to DC Converter - Switching", demonstrates a method to directly assess the open-loop frequency response, and hence the stability margin, of this converter. The TDFS (Time Domain Frequency Sweep) method circumvents the need for state-average models of the switching elements.

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Buck DC to DC Converter vs. Linear Regulator

Designer19

Member for

11 years 8 months

1,842

designs

10

groups

Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

Description

About text formats

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Automotive Buck Converter with NCV8851 - AC Analysis

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TDFS Loop Stability for Buck DC to DC Converter - State Average

Designer19

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Buck DC to DC Converter - Switching

Designer19

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Buck DC to DC Converter vs. Linear Regulator

Designer19

Member for