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Extended Range Pulsing for PXIe-4139 (40W)[1]

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    Last Modified: November 30, 2020

    The following figures illustrate the maximum pulse on time and duty cycle for the PXIe-4139 (40W) in a ≥58 W cooling slot, for a desired pulse voltage and pulse current given zero bias voltage and current. The shaded areas allow for a quick approximation of output limitations and limiting parameters. Actual limits are described by equations in Table 1.

    Figure 1. Pulse On-time vs Pulse Current and Pulse Voltage
    spd-note-note
    Note  

    Equations to solve for maximum pulse on time, tonMax, are shown in Table 1. Additionally, Equation 6 solves for pulse on time, ton, in terms of maximum pulse energy in Example 1: Determining Extended Range Pulse On Time and Duty Cycle Parameters for the PXIe-4139 (40W).

    Figure 2. Duty Cycle vs Pulse Current and Pulse Voltage
    spd-note-note
    Note  

    Equations to solve for maximum duty cycle, DMax, are shown in Table 1. Additionally, Equation 7 solves for pulse off time, toff, in terms of maximum pulse energy in Example 1: Determining Extended Range Pulse On Time and Duty Cycle Parameters for the PXIe-4139 (40W).

    Bias level limits

    Maximum voltage, Vbias

    60 V

    Maximum current, Ibias

    3 A

    Table 1. PXIe-4139 (40W) Pulse Level Limits
    Specification Value Equation
    Maximum voltage, VpulseMax 50 V
    Maximum current, IpulseMax 10 A
    Maximum on time, tonMax[2] If Ipulse > 3 A Calculate using the equation or refer to Figure 1 to estimate the value. t onMax = 2 ms * 7 A | I pulse | 3A , where  t onMax  is 167 s

    (Equation 1)

    If Ipulse3 A tonMax = 167 s
    Maximum pulse energy, EpulseMax[3] 0.4 J

    E pulse = | V pulse * I pulse * t on | , where E pulse <  E pulseMax

    (Equation 2)

    Maximum duty cycle, DMax[4] Calculate using the equation or refer to Figure 2 to estimate the value. D Max = (3.68 A) 2 | I bias | 2 | I pulse | 2 | I bias | 2 * 100%

    (Equation 3)

    Minimum pulse cycle time, tcycleMin 5 ms

    t cycle = t on + t off , where  t cycle > t cycleMin

    (Equation 4)

    Maximum cycle average power, PCAMax[5] ≥58 W Slot Cooling Capacity Chassis 40 W

    P CA = | V pulse * I pulse * t on | + | V bias * I bias * t off | t on + t off , where  P CA < P CAMax

    (Equation 5)

    <58 W Slot Cooling Capacity Chassis 10 W
    spd-note-note
    Note  

    Software will not allow settings that violate these limiting equations and will generate an error.

    • 1 Extended range pulses fall outside DC range limits for either current or power. In-range pulses fall within DC range limits and are not subject to extended range pulsing limitations. Extended range pulsing is enabled by setting the Output Function to Pulse Voltage or Pulse Current.
    • 2 Pulse on time is measured from the start of the leading edge to the start of the trailing edge. See Figure 1.
    • 3 Refer to Figure 1 to estimate the value and determine the limiting equation.
    • 4 Refer to Figure 2 to estimate the value and determine the limiting equation. If D≥100%, consider switching Output Function from Pulse mode to DC mode.
    • 5 Refer to Figure 2 to estimate the value and determine the limiting equation.

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