Switching Converter | PartQuest™ Explore

Step-Down (Buck) DC to DC Converter - Switching

Daniel Deitschel
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Daniel Deitschel

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Description

This design is a detailed circuit implementation of the more abstract "state-average" buck converter model shown in the companion design example: “Step-Down (Buck) DC to DC Converter - Continuous”. This example includes the low-pass voltage sense circuit, an op-amp implementation of the difference amplifier and the lead-lag compensator, as well as PWM switching control of a power MOSFET. Simulation results for the line and load transients are very similar to the results from the continuous model.This design uses a number of "datasheet characterized" components, including the power MOSFET (MCH6337), freewheel diode (NRVTS560EMFS) and op-amps (MC33272A), as well as the soft-saturation inductor (XAL6060-223) 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.The companion design, "TDFS Loop Stability for Step-Down (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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Step-Down (Buck) DC to DC Converter - Switching 2

Daniel Deitschel
Designer257

Daniel Deitschel

Member for

9 years 6 months

43

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Description

This design is a detailed circuit implementation of the more abstract "state-average" buck converter model shown in the companion design example: “Step-Down (Buck) DC to DC Converter - Continuous”. This example includes the low-pass voltage sense circuit, an op-amp implementation of the difference amplifier and the lead-lag compensator, as well as PWM switching control of a power MOSFET. Simulation results for the line and load transients are very similar to the results from the continuous model.This design uses a number of "datasheet characterized" components, including the power MOSFET (MCH6337), freewheel diode (NRVTS560EMFS) and op-amps (MC33272A), as well as the soft-saturation inductor (XAL6060-223) 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.The companion design, "TDFS Loop Stability for Step-Down (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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Mike debug Rosc on NCV881930 Virtual Demo Board

Mike Donnelly
Designer19

Mike Donnelly

Member for

11 years

1,697

designs

10

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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

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Step-Down (Buck) DC to DC Converter - Switching RSC

Coop
Designer24

Coop

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11 years

73

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Description

This design is a detailed circuit implementation of the more abstract "state-average" buck converter model shown in the companion design example: “Step-Down (Buck) DC to DC Converter - Continuous”. This example includes the low-pass voltage sense circuit, an op-amp implementation of the difference amplifier and the lead-lag compensator, as well as PWM switching control of a power MOSFET. Simulation results for the line and load transients are very similar to the results from the continuous model.This design uses a number of "datasheet characterized" components, including the power MOSFET (MCH6337), freewheel diode (NRVTS560EMFS) and op-amps (MC33272A), as well as the soft-saturation inductor (XAL6060-223) 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.The companion design, "TDFS Loop Stability for Step-Down (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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NCV881930 Virtual Eval Board

RobertDavis
Designer256

RobertDavis

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Demo New GUI for NCV6356

Mike Donnelly
Designer19

Mike Donnelly

Member for

11 years

1,697

designs

10

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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 copy of Norm's NCV6356 Demo Board Fastsim, used to demonstrate the use of a new GUI interface. This version just uses "static" (unchanging) values for the programmable parameters. Please see this example to learn to use the companion "injector" model for sending "dynamic" (time varying) programmable parameters to the NCV6356:https://www.systemvision.com/design/test-ncv6356-gui-and-injector-models------------------------------------------------------------------------------------- Hierarchical NCV6356 Demo Board buck converter.Ideal switches replace MOSFETs to maximize simulation speed. Best usage is to verify desired behavior over millisecond to tens of ms. Best used to monitor behaviors covering hundreds or more switching cycles.-------------------------------------------------------------------------------------Some useful waveforms can be displayed by probing the chip module. * Expand Fsw_cal and select tbase_rd_out to display Fsw regulation. tbase_rd_out seeks and maintains a constant level of 80 units by setting a controlling value in the Kton waveform. * Select state_of_chip to trace power-up sequence and ishort * Expand Ipk_detect and select N_violations to monitor progress towards ishort detection. * Overlay plots of FBint and Vintl to display voltage resolution,-------------------------------------------------------------------------------------See NCV6356_Demo_Board for an identical design using MOSFET switches to accurately account for power dissipation.-------------------------------------------------------------------------------------See wrap_NCV6356_combined for a schematic representation of the chip model. MOSFET and ideal switch versions are derived from a common netlist generated from this design with portions commented out.Version6_NCV6356_and_DemoBoard combines the above chip model with external buck converter circuitry to produce a single level flattened hierarchy usable to develop and test the chip model.

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NCV881930 Virtual Demo Board

RobertDavis
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RobertDavis

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NCV891930MW00 Virtual Conti01

ludovic
Designer199072

ludovic

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Description

This version of the NCV891930MW00 "Virtual Evaluation Board" represents most of the features of the 3.3 V/5.0 V output part. By changing various input stimulus and loading conditions, you can test these capabilities in the context of their intended usage.For the nominal configuration, the input voltage is set to 12V, the synci source is delayed for 10 msec (well beyond the simulation end-time), and the load resistance is fixed at 1 Ohm until 500 us, then it jumps to 10 kOhm for 100 us, then back to 1 Ohm. The soft-start operates normally, but during the high resistance operation of the load transient, a single pulse-skip interval is observed. You can zoom in on the PWM signal and see that only two 500 kHz pulses were applied during the “burst” interval, but it will generate 3 pulses under other operating conditions. You can also see that the PWM frequency is spread-spectrum after the soft-start is complete, by measuring the clock frequency (as a waveform) in the main waveform viewer.To test the “GH continuous ON” behavior, you can select the “DC” option in the load resistance function generator to set the value to a fixed 1 Ohm, and set the input voltage to 5.5V. In the simulation you'll observe several long periods of "continuous GH" operation, with 200 ns boost recharge windows every 16 us, after soft-start has finished.To test SYNCI operation, set the input voltage to 12V and the load resistance to “Pulse” (i.e. back to their original values), and then change the synci source delay to 10 ns (instead of 10 ms). Then the device will operate in forced PWM mode, with negative inductor currents allowed during the high load resistance period (i.e. not diode-emulation), and no pulse-skip. Other features can also be tested (high voltage frequency fold-back, output voltage select, LDO bypass jumper removed, etc.). In addition, you can force abnormal operating states using the two fixed logic sources available in the lower left corner of the schematic. For example, if the controller signal “d_spread_spectrum” is disconnected right at the input to the oscillator, and then a new net is connected from “d_set0” to that open input port, then the oscillator's spread-spectrum function will be disabled regardless of the normal controller commanded behavior.Notes: (1) Because a simplified version of the resistor divider network and compensation is used, the model will regulate above the target output voltage at light loads. The the real IC will regulate within specifications. (2) In order to reduce the simulation time, the softstart capacitor value has been adjusted to reduce the softstart time. The value used in this project does not reflect the suggested value from the evaluation board schematic. The desired capacitor value should be selected based on the equation provided in the datasheet.

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Fast (Ideal Switches) Version 8 of NCV891930 Virtual Eval Board

Mike Donnelly
Designer19

Mike Donnelly

Member for

11 years

1,697

designs

10

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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 version of the NCV891930 "Virtual Evaluation Board" simulates &gt; 4x faster than if full MOSFET switch models are used. This model represents most of the features of the part. By changing various input stimulus and loading conditions, you can test these capabilities in the context of their intended usage.For the nominal configuration, the input voltage is set to 12V, the synci source is delayed for 10 msec (well beyond the simulation end-time), and the load resistance is fixed at 1 Ohm until 500 us, then it jumps to 10 kOhm for 100 us, then back to 1 Ohm. The soft-start operates normally, but during the high resistance operation of the load transient, a single pulse-skip interval is observed. You can zoom in on the PWM signal and see that only two 500 kHz pulses were applied during the “burst” interval, but it will generate 3 pulses under other operating conditions. You can also see that the PWM frequency is spread-spectrum after the soft-start is complete, by measuring the clock frequency (as a waveform) in the main waveform viewer.To test the “GH continuous ON” behavior, you can select the “DC” option in the load resistance function generator to set the value to a fixed 1 Ohm, and set the input voltage to 5.2V. In the simulation you'll observe several long periods of "continuous GH" operation, with 200 ns boost recharge windows every 16 us, after soft-start has finished.To test SYNCI operation, set the input voltage to 12V and the load resistance to “Pulse” (i.e. back to their original values), and then change the synci source delay to 10 ns (instead of 10 ms). Then the device will operate in forced PWM mode, with negative inductor currents allowed during the high load resistance period (i.e. not diode-emulation), and no pulse-skip. Other features can also be tested (high voltage frequency fold-back, output voltage select, LDO bypass jumper removed, etc.). In addition, you can force abnormal operating states using the two fixed logic sources available in the lower left corner of the schematic. For example, if the controller signal “d_spread_spectrum” is disconnected right at the input to the oscillator, and then a new net is connected from “d_set0” to that open input port, then the oscillator's spread-spectrum function will be disabled regardless of the normal controller commanded behavior.

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NCV891930MW00 Virtual Demo Board

RobertDavis
Designer256

RobertDavis

Member for

9 years 6 months

135

designs

1

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Description

This version of the NCV891930MW00 "Virtual Evaluation Board" represents most of the features of the 3.3 V/5.0 V output part. By changing various input stimulus and loading conditions, you can test these capabilities in the context of their intended usage.For the nominal configuration, the input voltage is set to 12V, the synci source is delayed for 10 msec (well beyond the simulation end-time), and the load resistance is fixed at 1 Ohm until 500 us, then it jumps to 10 kOhm for 100 us, then back to 1 Ohm. The soft-start operates normally, but during the high resistance operation of the load transient, a single pulse-skip interval is observed. You can zoom in on the PWM signal and see that only two 500 kHz pulses were applied during the “burst” interval, but it will generate 3 pulses under other operating conditions. You can also see that the PWM frequency is spread-spectrum after the soft-start is complete, by measuring the clock frequency (as a waveform) in the main waveform viewer.To test the “GH continuous ON” behavior, you can select the “DC” option in the load resistance function generator to set the value to a fixed 1 Ohm, and set the input voltage to 5.5V. In the simulation you'll observe several long periods of "continuous GH" operation, with 200 ns boost recharge windows every 16 us, after soft-start has finished.To test SYNCI operation, set the input voltage to 12V and the load resistance to “Pulse” (i.e. back to their original values), and then change the synci source delay to 10 ns (instead of 10 ms). Then the device will operate in forced PWM mode, with negative inductor currents allowed during the high load resistance period (i.e. not diode-emulation), and no pulse-skip. Other features can also be tested (high voltage frequency fold-back, output voltage select, LDO bypass jumper removed, etc.). In addition, you can force abnormal operating states using the two fixed logic sources available in the lower left corner of the schematic. For example, if the controller signal “d_spread_spectrum” is disconnected right at the input to the oscillator, and then a new net is connected from “d_set0” to that open input port, then the oscillator's spread-spectrum function will be disabled regardless of the normal controller commanded behavior.Notes: (1) Because a simplified version of the resistor divider network and compensation is used, the model will regulate above the target output voltage at light loads. The the real IC will regulate within specifications. (2) In order to reduce the simulation time, the softstart capacitor value has been adjusted to reduce the softstart time. The value used in this project does not reflect the suggested value from the evaluation board schematic. The desired capacitor value should be selected based on the equation provided in the datasheet.

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Daniel DeitschelDesigner257

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Daniel DeitschelDesigner257

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Mike DonnellyDesigner19

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CoopDesigner24

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RobertDavisDesigner256

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Mike DonnellyDesigner19

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RobertDavisDesigner256

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ludovicDesigner199072

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Mike DonnellyDesigner19

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RobertDavisDesigner256

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Daniel Deitschel
Designer257

Daniel Deitschel
Designer257

Mike Donnelly
Designer19

Coop
Designer24

RobertDavis
Designer256

Mike Donnelly
Designer19

RobertDavis
Designer256

ludovic
Designer199072

Mike Donnelly
Designer19

RobertDavis
Designer256