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ADP2302 do not want to be loaded

August 20, 2015, 8:16 am
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Hi,

 

I'm currently prototyping a product in which I use an ADP2302 as a 12Vin/7Vout 1.8A regulator, but I'm facing a strange phenomenon.

 

When I measure the output without any load, everything is fine, I get 7 volts.

But as soon as I connect a load, the output drops dramatically, as if there were a short...

For example, a 1k resistor make the output drop to 5 volts. And if I try to draw 100mA, the output is almost zero.

 

The regulator seems unable to output enough current.

 

The IC seems to be working properly as it shows the expected behavior. I mean, it switches the inductor at 700kHz when the output is at 7V, but as soon as the output drops and the FB pin get under 0.6V, the switching frequency get divided.

 

So I suspect the inductor to be the culprit. But I dont understand what's wrong whith it...

Here the part number : ASPI-6045S-6R8M-T

Its specs seems to be well within the range, but maybe I'm missing something...

 

As for the PCB, Ok it does not look like an RF design as it should be, but I think I followed the rules : components close to the IC, high current traces are short and wide enough, BIG ground plane on the back of the PCB, short FB trace...

 

For reference, here are the Schematic, and a photo of the populated pcb.

 

Schem.png

IMAG1543.jpg

 

 

 

A great Thanks in advance to the one who'll find what I'm doing wrong ;-)

 

Fred

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ADD5211 design questions

December 10, 2015, 11:56 pm
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Hey all

 

I'm not happy with a current backlight solution I use on a custom board, it tends to blow up the driver IC for yet unknown reasons.

So I looked around for other LED drivers and found the ADD5211.

 

I've looked into the datasheet and also downloaded the calculation sheet, but now I'm not sure because I get completely different values than the example values in the datasheet and beside that I'm not sure which values I should use for calculation. I suppose I have to use the worst case values even if I might run the backlight at lesser current?

 

I have to drive 4 LED strings of a TFT backlight.

Each string runs at around 100 mA, max string voltage is 54V, at 100 mA probably less than 50V.

I also want to have an option to alter the string current if I have to use a different panel, so I might need more or less than 110 mA.

(In my current solution I just adjust the resistors that set the string current.)

 

As an inductor I want to use SRR1280-220M (22µH, Isat = 4.1A), which -if I'm not wrong- should be sufficient.

I selected SS5P9 as diode (If = 5A, Ifsm = 150A, 90V, could be replaced by SS5P10 if 100V would be better).

IRF7488 was chosen as NMOS switch (5A contin. drain current, 50A pulsed, Vds = 80V). Here I'm not that sure if it's okay to use this mosfet, but looking at the calculated values, it should be?

Switching frequency should be around 1000 kHz. (1070 kHz if Rfreq is 16 kOhm). I wouldn't mind changing the switching frequency, if anyone here says it's better to use more or less than that.

Minimum input voltage is around 23V.

 

Now, I'm not sure about the current sense resistor and the compensation parts.

 

Using the calculation sheet, Rcs is around 0.165 Ohm. What resistor should I use? 0.16 Ohm (are available as 1206 and 250 mW), or more/less than that?

If I calculate it correctly, Prcs is around 174 mW, so 250 mW should be safe?

 

About Cout: what values are suggested? I'm not going to use PWM dimming. Would it be better to use 4.7µF or rather 10µ or 22µF?

 

Altering the Cout capacity also alters the values of Rc and Ccomp. Rc's suggested value is 100 Ohm, is it okay to safely use other values such as 330 Ohm?

 

A quick calculation:

with Cout = 22µF, Rc would be 330 Ohm and Ccomp around 2.2µF. These values are common and available.

with Cout = 10µF, Rc would be 150 Ohm and Ccomp around 2.2µF, or 330 Ohm and 1µF. These values, too, are common and available.

But again, what Cout would be best and is it safe to use the just calculated values for Rc and Ccomp depending on Cout's value?

 

Whew, I hope this makes sense to you

I'd really appreciate some hints so I can design a better solution than my current one that causes troubles now and then ...

 

Thanks in advance and best wishes,

Robert

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ADM1276 Ground bounce

August 13, 2015, 1:57 am
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sir

When Vin=12V connect to ADM1276, I found the Ground bounce issue.

How to solve it?

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Could I have AD8250 model file?

September 11, 2015, 3:36 am
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Hi

I want to do the simulation of AD8250.

I made the model from "AD8250.cir" file.

But I couldn't simulate that.

Error message is below.

 

*** ERROR *** The circuit is too large to simulate with this version.

Too many analog nodes

 

Please provide the AD8250 model file?

and please give us the tips to go well .

 

 

Regards

moto

 

ADIsimPE  Release 7.20k

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Are there any SPICE simulation models for the ADP7142 & ADP7182?

September 14, 2015, 7:40 pm
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ADP125: Protection diode required?

October 24, 2015, 1:23 am
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Hi everyone,

 

I'm designing a circuit with some ADP125 LDOs for the analog supplies. In the abs. max. ratings, there is a requirement for VOUT:

 

VOUT to GND | -0.3V to VIN

 

This would clearly indicate that the regulator needs a reverse diode from VOUT to VIN, however, this is not present on the evaluation board. Since the pass transistor is a P-channel MOSFET, I'd expect there to be an internal diode anyway. So is there still an external Schottky required?

 

Thanks. Best regards,

Philipp

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In trouble simulating IN-AMP

December 9, 2015, 10:31 pm
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Hi there,

I'm in trouble to simulate IN-AMP, AD623.

I'd like to check transient analysis, but for some reason the output of AD623  does not work....

There is the error message,

"

Device AD623 found in C:\Program Files\ADIsimPE_720\support\Models\analog_devices_linear_encrypted.lb

Error : Cannot find vector of name 'U1_OUT'

"

I think this is the model issue, can you tell me how to fix this problem?

My virsion is 7.20 and I attached the file just in case.

 

Best regards,

Tarzan

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I have a small query on ADP5585?

January 19, 2016, 6:21 am
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Hi Team,

 

In my product I am using ADP5585 KP controller IC and my circuit is like below figure,

 

WP_20160119_008.jpg

 

now my query is,

 

1. I am not able to read R0xC0 configuration?

2. is nINT pin always shows high?

 

and I am able read KP IC slave ID but rows and columns not working, please clarify this.

 

Thanks,

Jakkireddy.

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Need your recommendation about AC/DC Power Solution

July 31, 2015, 12:33 am
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Hello,

 

My customer is preparing a IoT product with WiFi.

And they want to supply DC power to WiFi soution using AC power.

So they need AC/DC solution for this.

 

Their WiFi solution will use 3.3V.

 

Would you recommand AC/DC solution of ADI ?

 

Please advise me.

 

If you have any questions, please let me know.

 

Regards,

Se-woong

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ADM1278- Any script/xcel file available?

August 27, 2015, 8:26 am
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Hello

From one of my customers:

Do you have a configuration file in order to set all the voltage dividers values, power, etc..? for example an excel file?

Thanks

Freddy

 

 

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ADP1712 Enable/Disable Voltage Tolerance

January 26, 2015, 2:07 pm
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In reference to Figure 30 in the current revision of the ADP1712 datasheet, what type of variation can we expect on these voltages? 

EZ-ADP1712_01.PNG

In the following test circuit, we changed R2 to 49.9k and R3 to 16.2k. Using a meter to adjust the supply voltage, I adjust the VIN voltage to 5.01V (as close as I can get with my hand-dial control and hand-held meter measurement) and I measure the voltage at the enable pin to be 1.215V. Assuming zero tolerance on the resistors, we would expect the voltage to be 1.225V when VIN = 5V, but with resistor tolerance and the leakage current into the enable pin, I can understand that being 10mV lower than expected.  What I am scratching my head over is that this does not result in activation of the ADP1712's output.  Based on Figure 30, it would seem like anything above 1.2V would cause activation.  Perhaps my meter is not well calibrated but there is more on this below.

EZ-ADP1712-02.png

As I increase the VIN voltage, I find that it starts when VIN reaches ~5.25V, result in VEN  = 1.27V according to my meter.

In the next step, I changed R3 to 16.5k and noticed that the device would start at VIN = 4.97V, resulting in VEN = 1.225. 

Taking this one more step, I changed R3 to 16.9k and the ADP1712 enabled the output voltage when VIN = 4.76V, resulting in VEN = 1.202V.

 

Any thoughts on this? Am I missing anything or could I be dealing with a meter that is out of calibration?

 

Thanks!

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ADG836L

December 27, 2015, 4:22 am
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HI Sir,

 

ADG836L is Dual SPDT/2:1 MUX; this part can use  input negative -5V and +5Vcc, then output negative -5V and +5Vcc? or only ADG1636( 1 Ω Typical On Resistance, ±5 V, +12 V, +5 V, and +3.3 V Dual SPDT Switches) can useage input negative -5V and +5Vcc, then output negative -5V and +5Vcc?

 

Thank you.

 

Vincent.

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ADP5585 configuration of Registers

July 4, 2013, 7:42 pm
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Hello Friends,I  start using this IC of ADP5585 recently,and now I don't know how to use it.I want to use it as a matrix keyboard,and the problem that I meet is I don't know how to configure the relevant registers. In other words,what can I do to make it work well?Thank you!

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.step file (or .iges) for ADP7102

December 16, 2015, 7:13 am
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"Ultra librarian" (boy, does this UI need a complete re-do), produces a 2D dxf (despite selecting 3D).  When I try to export the STP/STL model, I get Component "ADP7102ARDZ-R7" renamed to "ADP7102ARDZ-R7" and no model.

 

Is there a better tool available or perhaps models posted on the Analog web site that we may use?

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ADP1047 using for DC/DC

August 4, 2014, 1:51 am
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Hello,

 

could the ADP1047 be used for DC/DC design? I want to design a SEPIC controller like this one:

 

http://www.analog.com/static/imported-files/application_notes/AN-1126.pdf

 

The requirements are as follows:

 

Vin=12-15V

Iin=20A-40A

Vout=100V-500V

Iout=0.5A-0.8A

 

It wold be nice to use this controller becouse of abbility for adjusting the Vout. If it is possibel, what settings should I make and should I make changes to the hardware?

 

Thanks a lot!

 

Eugen

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ADN8831 Operation

July 28, 2015, 9:10 pm
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Hello,


I have a question to the TEC controller chip.

 

My laser diode output depends on the temperature.

 

So, using the TEC controller chip, i want to maintain the temperature automatically when the laser output is 1W.

 

In other words, the laser diode output of 1W is input to the photodiode and photodiode output is some voltage value.

 

At this time, using this voltage value, then the temperature of the object voltage value and the like to be connected to a reference temperature set pin.

 

If so, whether it is set to maintain the temperature for laser output of 1W?

 

Repeat gritty, When i make the typical application circuit in the ADN8831ACPZ-REEL7 manual, i want to maintain the TEC temperature when the laser output packaged with TEC reaches to 1W.

 

if i can, how?

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Could I have AD8250 model file?

September 11, 2015, 3:36 am
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Hi

I want to do the simulation of AD8250.

I made the model from "AD8250.cir" file.

But I couldn't simulate that.

Error message is below.

 

*** ERROR *** The circuit is too large to simulate with this version.

Too many analog nodes

 

Please provide the AD8250 model file?

and please give us the tips to go well .

 

 

Regards

moto

 

ADIsimPE  Release 7.20k

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adp1048 - Which conduction mode?

November 4, 2015, 1:35 am
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Dear all,

 

we plan to use the adp for an intreleaved boost pfc (3.6kW). I can't find any Information regarding the used conduction mode of the Controller. Is it continious, discontinious or critical conduction mode?

 

Thank you!

 

regards Christian

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Current Source for LASER diodes

January 22, 2016, 6:00 am
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Hi,

 

I am looking for a current source for the LASER diode. I want to increase the input current to the LASER in steps of 0.1mA. Current requirement for my LASER is in the range of 25-45mA.

Can anybody suggest a suitable product?

 

Regards,

Nidhi Singh

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Is there a way to integrate and simulate ADP5090 Model(SIMPLIS) and AD8210(SiMetrix) into a single circuit?

October 15, 2015, 8:05 pm
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Hello,

 

    I'm new to ADIsimPE and  trying to simulate a regulator circuit with current/power monitoring. This leads me to using ADP5090 for regulator and AD8210 current shunt monitor IC into a single circuit, but I'm having below error prompts during simulation:

 

if using SIMetrix:

 

*** ERROR *** Cannot find definition for sub-circuit 'ADP5090_Model'

 

 

if using SIMPLIS:

 

Unable to locate the definition

of `subcircuit AD8210' in the

input, include, or library file(s).

 

     I'm curious if we can simulate both components into a single circuit? Appreciate if you can share some work-around to this.

 

Thanks,

Versil1

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