Repetitive pulse loading

Typically, a load current is not constant and varies over time. This power supply is designed to support loads with a higher short-term power demand (=BonusPower). The short-term duration is hardware controlled by an output power manager and is available on a repeated basis. If the BonusPower load lasts longer than the hardware controller allows it, the output voltage will dip and the next BonusPower is available after the BonusPower recovery time (see chapter “Output”) has elapsed.

To avoid this, the following rules must be met:

• The power demand of the pulse must be below 150% of the nominal output power.
• The duration of the pulse power must be shorter than the allowed BonusPower time. (see output section)
• The average (R.M.S.) output current must be below the specified continuous output current. If the R.M.S. current is higher, the unit will respond with a thermal shut-down after a period of time. Use the maximum duty cycle curve (Fig. “Max. duty cycle curve”) to check if the average output current is below the nominal current.
• The duty cycle must be below 0.5.:

P₀ Base load (W)
P_PEAK Pulse load (above 100%)
T₀ Duration between pulses (s)
T_PEAK Pulse duration (s)

DutyCycle = T_PEAK / (T_PEAK + T₀)

T₀ = (T_PEAK - (DutyCycle x T_PEAK)) / DutyCycle

Example:

A load is powered continuously with 480W (= 50% of the rated output load). From time to time a peak power of 1440W (= 150% of the rated output load) is needed for 1 second.

The question is: How often can this pulse be supplied without overloading the power supply?

• Make a vertical line at P_PEAK = 150% and a horizontal line where the vertical line crosses the P₀ = 50% curve. Read the max. duty cycle from the duty cycle-axis (= 0.37)
• Calculate the required pause (base load) length T₀:

T₀ = (T_PEAK - (DutyCycle x T_PEAK)) / DutyCycle

T₀ = (1s- (0.37 x 1s)) / 0.37 = 1.7s

• Result: The required pause length = 1.7s
• Max. repetition rate = pulse +pause length = 2.7s

More examples for pulse load compatibility