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We are investigating the process. It looks like the origin is the use of an aggressive PCB cleaner (Water based Alkaline) that may not be totally compatible with Immersion Silver PCBs, specially after some reflow cycles...
Hi!
I am having an issue with a PCB after soldering. Apparently, the plating can be easily peeled. This is a major quality problem as the copper can be exposed and solder quality is not guaranteed.
We have detected this after reflow soldering and the source is unclear.
Do you think it is...
I was wondering if there any other standard connectors for Ethernet :thinker:. Traditional RJ45 are huge for some space constrained applications :|.
Thank you!
Hello!
I would like to use a web based tool to improve project and resources management in my engineering team. Do you have any recommendation based on your experience?
Minimum features:
- Time tracking.
- Gantt.
- Easy to work with.
- Web based.
- Resources management
Thank you!
Ernest
Note that there are thousands of hysteric step-down converter control IC's for LEDs. Anyway if you want to design it by yourself and want to simplify the circuit I would suggest using an operational amplifier wired as a Schmitt trigger comparator. The input of the comparator should come from the...
Turn on gate resistance of 22 ohm seems right. However during turn off (gate discharge) the current flows through the schottky diode without resistor limitation. This is why I suggest adding a resistance in series with the diode.
Regarding the higher current driver there are several options...
With this MOSFET IRF3205 and the gate driver you are using should be OK.
I would suggest using a resistor in series with the turn-off diodes UF4007. If Vdd is 12 V I would say 6 ohm resistor in series as a first approach, this will limit current to < 2 A and reduce power loses in the driver.
Firstly I would suggest to increase the pull-down resistors from 1 kohm to 10 kohm to reduce bootstrap discharge and consumption.
Which PWM frequency are you using and which is the gate charge of the MOSFETS? It is normal that the gate driver becomes hot when charging and discharging a MOSFET...
This "Zener" represent the avalanche behaviour of MOSFETS that start conducting current when a certain drain to source voltage is applied. Properly designing a MOSFET to operate in avalanche region is not easy and if not properly designed it would cause the MOSFET to fail See...
I agree, it is not clearly explained in the datasheet. My experience is with VIPER27 and VIPER17. I have implemented power supplies with those ICs and they do not turn on until Vdrain reaches 60 V ... 100 V according to the datasheet. I tried to design an external power-up circuit (see...
The Viper 22A will not turn on until VDS > 100 V. With VDS < 100 V it will not charge Vdd capacitor. Figure 10 https://www.st.com/web/en/resource/technical/document/datasheet/CD00087939.pdf
You may be able to operate at 40 VAC if you start-up at 100 V and then you decrease.
Regarding Vdd...
The typical approach is using a step-down or buck converter or a flyback converter. Linear regulator from 120 V would be extremely inefficient!
While a 125V input buck IC may be a bit difficult to find, there are many flyback converter solutions like Power Integrations TOP243GN-TL that should...
The differential amplifier you sent should measure across motor terminals.
Note that common mode rejection ratio of the circuit will be critical to sense motor voltage properly --> Use matched precision resistors (0.1%) for the amplifier circuit as well as low tolerance stable capacitors C0G / NP0.
Hello!
I am designing a power system that includes an IGBT module with E3 package.
**broken link removed**
These modules are usually mounted to heatsink with thermal grease for best thermal transfer. However I would like to use other materials to ease the assembly process and improve thermal...
Re: How to reduce VIPER17 start-up voltage (from the default ≈100 Vdc to 50 Vdc)
I have already tested this precharge circuit to power the IC externally and it still does not work. Definitively, the VIPER requires a drain voltage between 80V and 100V to start operation. I will need to switch to...
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