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Description

This version of the NCV891930 "Virtual Evaluation Board" 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.Note: This version is different from Version 7 because it now includes the Renlo internal load resistance that is activated when the output voltage exceeds the target voltage by 7.5%. It will also now function in continuous-on mode at low input voltage when using either the local rosc (which is in foldover mode) or synci if it has a valid synci input signal. 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.

NCV891930 Demo Block Testing Datasheet FETs

RobertDavis
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RobertDavis

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9 years 6 months

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NCV891930MW01 Virtual Demo Board

RobertDavis
Designer256

RobertDavis

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9 years 6 months

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Description

This version of the NCV891930MW01 "Virtual Evaluation Board" represents most of the features of the 3.65 V/4.0V 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.

NCV891930MW01 Model

RobertDavis
Designer256

RobertDavis

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9 years 6 months

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NCV891930 Demo Block Testing Fast

RobertDavis
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RobertDavis

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Buck DC to DC Converter - save and regenerate waveforms

Test Account for SystemVision - mail.com
Designer138341

Test Account for SystemVision - mail.com

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7 years 4 months

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Description

This design is a copy of Mike Donnelly's Buck DC to DC Converter modified to demonstrate data reduction for downloaded waveforms. For more information about the buck converter you can find Mike's design athttps://www.systemvision.com/design/buck-dc-dc-converter-switchingThis design ramps up internal voltages for a simplified model of softstart. Mike's load transient is timed to activate after steady state. The L1 current rises after an initial spike. This current charges the output cap to generate a rising output voltage. That output voltage rises past the 5V setpoint until steady state sets in around 5.5V. After that Vout settles back to its steady state level. The load transient triggers disturbances in Vout at both edges of the transient.For further analysis of steady state and line/load transients, an x-sampling voltage source is added to reduce the size of the .csv data and to skip over startup. Data reduced files are generated in an Excel post-processing session based on the x-sampling voltage peaks.The reduced data can be read back into SystemVision or other appllications to display the waveforms,compare them to waveforms from another source or use them as sources in further simulations.

TDFS Impedance Stability of Transmission Line Fed LED Driver - Switching

MASA
Designer208

MASA

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9 years 9 months

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Description

This example demonstrates the use of the TDFS method (Time Domain Frequency Sweep) to measure impedance stability ratio. The system is a switching DC/DC step-down power converter used for LED lighting, supplied by a battery through a long power cable.The TDFS impedance stability measurement model applies a 0.2A sinusoidal stimulus current at the point where the cable connects to the converter. The voltage at that point, as well as the stimulus current splits (toward the source and the load) are measured, and the associated source and load impedances vs. frequency are computed.The ratio of the source to load impedance is the impedance stability ratio (Tm). Similar to the open-loop frequency response requirement for closed-loop stability, Tm must not have magnitude = 1.0 at phase = 180 degrees, at any frequency.For this system, with a cable length of 400 meters and 8 AWG wire, the results show that the impedance ratio magnitude (green waveform) reaches unity (0 dB) at close to 2 kHz, where the phase (light blue waveform) is approximately 165 degress. This implies a "phase margin" of only 15 degrees, For a longer cable, this margin is further reduced. As shown in the companion example, "Transmission Line Fed LED Driver - Switching", for the cable length = 800 meters the system is unstable.This instability is the result of the "source" impedance (which includes the cable) variation over frequency, interacting with the varying load impedance. Note that at low frequency, the load effectively has a negative impedance, due to the constant power nature of the DC to DC converter.

NCV881930 Symbol Only

RobertDavis
Designer256

RobertDavis

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Description

This version of the NCV891930 "Virtual Evaluation Board" 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.Note: This version is different from Version 7 because it now includes the Renlo internal load resistance that is activated when the output voltage exceeds the target voltage by 7.5%. It will also now function in continuous-on mode at low input voltage when using either the local rosc (which is in foldover mode) or synci if it has a valid synci input signal. 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.

Mike's run of NCV891930 Virtual Demo Board

Mike Donnelly
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Mike Donnelly

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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" 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.Note: This version is different from Version 7 because it now includes the Renlo internal load resistance that is activated when the output voltage exceeds the target voltage by 7.5%. It will also now function in continuous-on mode at low input voltage when using either the local rosc (which is in foldover mode) or synci if it has a valid synci input signal. 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.

NCV891930 Virtual Demo Board

RobertDavis
Designer256

RobertDavis

Member for

9 years 6 months

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Description

This version of the NCV891930 "Virtual Evaluation Board" 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.Note: This version is different from Version 7 because it now includes the Renlo internal load resistance that is activated when the output voltage exceeds the target voltage by 7.5%. It will also now function in continuous-on mode at low input voltage when using either the local rosc (which is in foldover mode) or synci if it has a valid synci input signal. 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.