I am using the SI3402 chip to use POE.
But it does not work properly.
The circuit I have constructed is as follows.
POE: SI3402 (non-isolated)
Ethernet Transceiver: H2019NL
When POE cable is plugged in, it charges for the first time but it becomes impossible to charge soon. I think that the POE side circuit is a problem because I operate normally when only 5V is applied to the charge IC.
Since it is confirmed that 5V is output from the output terminal, it is not a voltage problem.
I attach the schematic that I composed with PDF.
Please make sure that there is something strange in my circuit.
we are planning to use Si8233BD-D-IS driver for one of our motor inverter project. in the datasheet , it is specified as High electromagnetic immunity in the key features.
I want to know, this driver will protect against the overshoots( that may cause EMI) during switching transitions.
Also please provide the maximum active current values for both input and output side power supplies. typical values only provided in data sheet.
This is with reference to the Si824x reference kit.
1. In order to modify the gain, would it be correct to change R29 and R30 (4.99kohms), such that doubling the value will double the gain?
2. For bridge application, what would be a the recommended: use two mono channels with 180deg phase shifted signals or use the unused pin 8 of the comparator to drive another half bridge using a 2nd Si824x, in which case the feedback of the 2nd half bridge will drive the non-inverting pin of the error amplifier (IC17B/ 18B) as shown in the attachment?
Is it possible for these isolators to be operated with different supply voltages? For example: VDD1=5.0V, VDD2=3.3V.
And, if you have something I must pay attention or drawbacks when i use them in such way, please let me know it.
We are presently using a Si8931 isolated amplifier for high-speed measurements in a high-power motor drive.
One issue we are facing with our system is the possibility of the input amplifier to be supplied with a negative voltage lower than the min -0.5V stated in the data sheet.
The input source voltage can be as low as -4V for 1% of the time and -1.5V for up to 80% of the time.
Can we protect the amplifier with an external series resistor and how can we evaluate its value?
I am totally new to this forum looking for a help. Any tips and advice regarding my issue would be appreciated. I am jacksonlevi, working in a Corporate animation Company. I wanted to know that could the VDDA and GNDA actually be configured such that if, for example, a +15V/-5V bi-polar type biasing be fed into the chip and the source/emitter return of the device connected to separate neutral point?Or a different way could be that a 20V supply be placed between those pins, then using a secondary zener diode with resistors and capacitors create a +15V/-5V gate biasing ckt w/ a derived, floating source/emitter return point.Is there anything in the chip itself that would prevent negative biasing or reverse current flow? I have serached for this issue but did not find any right solution. Please help me
Any help would be greatly appreciated!!
We have a problem with si3402-B based PoE circuit. Some of devices are producing significantly notable sound when working. Some of them just light buzzing.
It seems there is an oscilation over optocoupler feedback and isolation transformer is making the sound. We are using PC3H7J00000F optocoupler. Schematic is attached.
Could you give us some advice how to eliminate the problem.
We are using the SI3404 chip to use POE, When we used the standard PoE injectors, it works perfectly.
But when we used the non-standard PoE injectors, the chip would burn out occasionally.
Our design is a reference of Si3404-Buck EVB board. Is the SI3404 not support the non-standard PoE injectors ?
Thank you for your Help.
Is an external gate resistor required to limit the initial peak current to the specified max source and sink currents? The MOSFET I am driving has an internal gate resistance of 0,25 ohm. (2x BSB056N10NN3) With V_DD=12V and R_N=1,0 ohm, the peak sink current will be 12V/1,25ohm=9,6A, which exceed the max specified sink current of 4,0A. Should I add an external gate resistor so that R_total=12V/4A? I.e. an external gate resistor of 1,8ohm. However this increase the switching losses as described in AN490.
(The power dissipation is well below the limits. The question is only about the driver output peak current and is not dependent on the gate charge.)