Dear sir
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Dear sir
Venkat,
Can you provide the design specs such as switching frequency? Also a schematic will help debug the issue you are having.
For a quick reference please use the quickstart calculator to verify your design. It is at the link below.
http://www.ti.com/lit/zip/snvu065
Thanks,
Garrett
8228.DC TO DC CIRCUIT 10.05.2016.pdfDear sir
In put Voltage: 9 to 16VDC and Out put Voltage:12.5V@6.0A ,Switching Frequency:300Khz.
Please give the calculated values.
Awaiting for your valuable replay.
With regards
B Venkat reddy
Venkat,
Below are a few component values that should be changed for proper operation. It is very easy to calculate these values using the quick-start tool that is linked above.
These changes will make the converter stable.
1. Ramp Capacitor: C6 = 330pF
2. Compensation Pole Capacitor: C10 = 1nF
3. Compensation Zero Capacitor: C11 = 33nF
4. Compensation Resistor: R7 = 8.8kOhm
These changes will let the UVLO and hiccup mode function properly.
1. R1 = 30kOhm
2. R3 and R4 in parrallel should be 8.35kOhm (This will set the UVLO to around 5.5V)
Also please make sure that sense resistor is kelvin connected to the CS and CSG pins, This will help with noise on the current sense signal.
-Garrett
Dear sir
we have modified as per above modification ,but out put current delivery 0.6A only.
Ramp Capacitor: C6 = 330pF one more capacitor connected to parallel 330pf , out put current increase to 1.30A.
product efficiency at 16.0VDC ,86% only. input Voltage below 16.0VDC efficiency decreases that is less then 75%.
Please find the attached photo graph.
Please give the calculated values. not under stand kelvin connected to the CS and CSG pins.
Please give the solution immediately.
With regards
B Venkat reddy.
PHOTOS.rarDear sir
we have modified as per above modification done.but out put current delivery 0.6A only.
Ramp Capacitor: C6 = 330pF , one more capacitor Connected to parallel 300pf out put current increases that is 1.30A.
Product efficiency at 16VDC 86% only,below 16.0VDC efficiency decrease that is less then 75%.
Please find attached photo graph.
Please give the calculated values. not under stand kelvin connected to the CS and CSG pins.
Please give the solution immediately.
With regards
B Venkat reddy.
Venkat,
The compensation values above are acceptable.
From what you described it sounds like you are hitting the inductor current limit. Please check the UVLO pin it see if it gets pulled low around every 256 clock cycles. This will indicate if the IC is in current limit.
Kelvin sensing will help with any noise on the current sense signal. Kevlin sensing is shown in the picture below. The CSG pin should be directly connect to the current sense resistor. It is also a good idea to have the RC filter on the sensed current pin to further help with noise.
Thanks,
Garrett
Venakt,
Please send me a personal message (PM) and we can debug the issue over email.
-Garrett
Dear sir
Please give the your personal message (PM) ID.
With regards
B Venkat reddy
Dear sir
Please give the your personal message (PM) ID.
With regards
B Venkat reddy
Dear sir
Iam awaiting for your valuable replay. and give the solution immediately .
Wth regards
B Venkat reddy
Dear sir
Iam awaiting for your valuable replay .
With regards
B Venkat reddy
Venkat,
Those numbers seem a little low. Can you tell me what is getting hot on the board?
The one thing that stands out to me right away is that that the diodes you selected have a forward drop of up to 0.92V. For this topology that can really kill efficiency, selecting a diode with a smaller voltage drop will help efficiency. Also the inductor may have high DCR and that could be effecting your efficiency
-Garrett.
Venkat,
Please provide your most recent schematic and BOM. This way I can help you check for any issues that maybe causing a drop in your efficiency measurement.
Thanks,
Garrett
DC TO DC CIRCUIT 21.06.2016.pdfDC TO DC CONVERTOR BOM 12.5V@6.0A 20.06.2016.xlsx.pdfDear sir
Please find the attached recent schematic and BOM.
Give the feed back immediately.
With regards
B Venkat reddy
Dear sir
Please give the feed back very soon.and that projuct very urgengy for customer .
Awaiting for your valuable replay.
With regards
B Venkat reddy
Dear sir
Please give the suggested out put diodes and mosfets.
and give the part number also.
With regards
B Venkat reddy
Dear sir
Please give the suggested out put diodes and mosfets.
and give the part number also.
With regards
B Venkat reddy
Dear sir
Please give the suggested out put diodes and mosfets.
and give the part number also.
With regards
B Venkat reddy
Venkat,
The diodes for the EVM are a good starting point. Here is the part number of the diode that we use on that module, VB40100C-E3/4W. Before you switch to this diode please make sure that it will handle the current levels.
-Garrett