Part Number:TLV62130
HI team,
Our customer posted double drive pulse issue in light load condition in his application, as following, and attached wave forms.
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Two TLV62130RGTT's are being used, one on each of two isolated channels. The loading on the parts are nearly identical. I am looking at the SW pins on each and both appear to be in power save mode.
Channel A seems to be providing the single pulse with ringing as shown in the datasheet. The pulse is supplied at intermittent, but roughly similar timing to keep voltage of rail at 4.98V. On Channel B, I am seeing the SW output alternate between a double-pulse with ringing every couple cycles and single pulse with ringing output with the single pulses more frequent than on Channel A. Channel B rail measured 5.02V. Looking through your application notes, I never saw the mention of two pulses being fired back-to-back like that in power save mode. Is this expected operation or cause for concern?
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I have commented to check voltage method and adding an input capacitor.
However, double drive pulse conditions did not change, as following his second quiary,
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Well for the board layout, both channels are laid out the same way. The layout of the board is basically a mirror image from Channel A to Channel B split down the center of the PCB. One channel is single pulsing, the other is going back and forth between double pulsing and single pulsing. I added an extra 10 uF of capacitance to the input capacitor and saw no change in the output at SW, the double pulsing was still present. I also made sure to use a twisted pair of wires connected directly from the oscilloscope probe’s tip and ground lead connection to the SW output pin and GND side of C106. Again, the double pulsing is still present. I am more curious as to whether the double pulse that I am seeing is an issue. With the inductor, the +5V rail is still consistent and sits at 5.02V. Does the double-pulse indicate that there is an issue with chip’s performance? Could the double-pulsing result in a failure? Or is the double-pulsing acceptable so long as the output rail is solid?
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What kinds of other problems are considered?
We will very appreciate for your help.