The following figures illustrate the maximum pulse on time and duty cycle for the PXIe4139 (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.
Equations to solve for maximum pulse on time, t_{onMax}, are shown in Table 1. Additionally, Equation 6 solves for pulse on time, t_{on}, in terms of maximum pulse energy in Example 1: Determining Extended Range Pulse On Time and Duty Cycle Parameters for the PXIe4139 (40W).
Equations to solve for maximum duty cycle, D_{Max}, are shown in Table 1. Additionally, Equation 7 solves for pulse off time, t_{off}, in terms of maximum pulse energy in Example 1: Determining Extended Range Pulse On Time and Duty Cycle Parameters for the PXIe4139 (40W).

Specification  Value  Equation  

Maximum voltage, V_{pulseMax}  50 V  —  
Maximum current, I_{pulseMax}  10 A  —  
Maximum on time, t_{onMax}^{[2]}  If I_{pulse} > 3 A  Calculate using the equation or refer to Figure 1 to estimate the value. 
${\text{t}}_{\text{onMax}}=\text{2 ms}*\text{\hspace{0.17em}}\frac{\text{7 A}\phantom{\rule{0ex}{0ex}}}{\text{}{\text{I}}_{\text{pulse}}\text{}\text{3A}}$
$\text{, where}{\text{t}}_{\text{onMax}}\text{is}\le \text{167 s}$
(Equation 1) 
If I_{pulse} ≤ 3 A  t_{onMax} = 167 s  —  
Maximum pulse energy, E_{pulseMax}^{[3]}  0.4 J 
${\text{E}}_{\text{pulse}}={\text{V}}_{\text{pulse}}*\text{\hspace{0.17em}}{\text{I}}_{\text{pulse}}*\text{\hspace{0.17em}}{\text{t}}_{\text{on}}$ ${\text{, where E}}_{\text{pulse}}{<\text{E}}_{\text{pulseMax}}$ 

Maximum duty cycle, D_{Max}^{[4]}  Calculate using the equation or refer to Figure 2 to estimate the value. 
${\text{D}}_{\text{Max}}=\frac{{\text{(3.68 A)}}^{\text{2}}{\text{}{\text{I}}_{\text{bias}}\text{}}^{2}}{{\text{}{\text{I}}_{\text{pulse}}\text{}}^{2}{\text{}{\text{I}}_{\text{bias}}\text{}}^{2}}*\text{100\%}$
(Equation 3) 

Minimum pulse cycle time, t_{cycleMin}  5 ms 
${\text{t}}_{\text{cycle}}={\text{t}}_{\text{on}}+{\text{t}}_{\text{off}}$ $\text{, where}{\text{t}}_{\text{cycle}}{\text{t}}_{\text{cycleMin}}$ (Equation 4) 

Maximum cycle average power, P_{CAMax}^{[5]}  ≥58 W Slot Cooling Capacity Chassis  40 W 
${\text{P}}_{\text{CA}}=\frac{{\text{V}}_{\text{pulse}}*\text{\hspace{0.17em}}{\text{I}}_{\text{pulse}}*\text{\hspace{0.17em}}{\text{t}}_{\text{on}}+{\text{V}}_{\text{bias}}*\text{\hspace{0.17em}}{\text{I}}_{\text{bias}}*\text{\hspace{0.17em}}{\text{t}}_{\text{off}}}{{\text{t}}_{\text{on}}+{\text{t}}_{\text{off}}}$ $\text{, where}{\text{P}}_{\text{CA}}{\text{P}}_{\text{CAMax}}$ 
<58 W Slot Cooling Capacity Chassis  10 W 