Waveforms
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4.2
Load Transient
Figure 3
shows the transient response for a load of change from 2A to 6A on 3.3V output. The upper
waveform shows output voltage droop and overshoot during the sudden change in output current shown
by the lower waveform.
Conditions:
Input Voltage = 12VDC
Output Current 2A to 6A
Traces:
Top Trace: 3.3V Output Voltage, Volt/div = 100mV, AC coupled
Bottom Trace: Output Current Amp/Div = 2A
Horizontal Resolution = 0.5 ms/div
Figure 3. Load Transient Response
4.3
Over Load Protection
The evaluation board is configured with hiccup mode overload protection. The restart time can be
programmed by C11.
Figure 4
shows hiccup mode operation in the event of an output short on CH1
output. One channel may operate in the normal mode while the other is in hiccup mode overload
protection.
Conditions:
Input Voltage = 12VDC
Output Short on 3.3V
Traces:
Top Trace: SW voltage on CH1, Volt/div = 10V
Bottom Trace: Inductor Current Amp/div = 10A
Horizontal Resolution = 20 ms/div
Figure 4. Short Circuit
4
AN-2066 LM25119 Evaluation Board
SNVA445B – August 2010 – Revised April 2013
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