Help identifying a 6-pin SMD IC in a power supply. - Page 1
Forum section: electronics / beginners

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: September 26, 2017, 01:30:30 pm
content: Guys,Could you help me identify the 6-pin SMD integrated circuit, that functions in the schematic attached below (marked in blue)?The SOT23-6 package has the markings C1EH (or CIEH) and 9013, but I cannot find these markings in any datasheets I looked at.Thanks in advance,Gonzo

author: jdraughn
author_rank: Regular Contributor
timestamp: September 26, 2017, 10:12:15 pm
content: Looks pretty closehttp://www.richtek.com/m/Products/AC_DC/Flyback%C2%A0Controller/R7711A

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: September 26, 2017, 10:29:25 pm
content: Thank you for trying to help me, unfortunately the R7711A chip has the VDDon Pin3 and the Gate driver on Pin1, while this mystery chip has the VDDon Pin1 and the Gate driver on Pin3.Also, the SOT23-6 markings are different. See the attached datasheet...

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 15, 2017, 10:57:21 pm
content: Some additional info.The switching frequency of this mystery IC is 24kHz.

author: BrianHG
author_rank: Super Contributor
timestamp: October 16, 2017, 03:09:52 am
content: You have Pin1 mislabeled in your schematic. Rotate the R7711A by 180 degrees in the data sheet and see how the pins line up.However, I still can be wrong... Because now, pin 6 and 4 are actually backwards.Did you draw this schematic?

author: xavier60
author_rank: Super Contributor
timestamp: October 16, 2017, 06:53:17 am
content: If that diagram is drawn correctly, the control IC is expecting a negative voltage on its CS pin with respect to its ground pin, witch is unusual.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 18, 2017, 09:29:17 pm
content: Quote from: BrianHG on October 16, 2017, 03:09:52 amYes, I drew this schematic by reverse engineering the PCB. I arranged IC pins that way on this drawing, so there are minimum wire intersections.Below isthe sameschematic with these IC pins arranged in a different way. I triple checked that it is correct.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 18, 2017, 09:35:24 pm
content: Quote from: xavier60 on October 16, 2017, 06:53:17 amIf you mean Pin1, I don't know what you mean.IMO both the 22uF cap and the diode feeding it through the 10Ohm resistor, are arranged to feed Pin1 with a positive voltage.

author: xavier60
author_rank: Super Contributor
timestamp: October 18, 2017, 10:26:12 pm
content: I should have said Current Sense pin 6.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 19, 2017, 07:25:05 pm
content: Quote from: xavier60 on October 18, 2017, 10:26:12 pmIndeed the voltage is negative on Pin6 while the MOSFET is conducting,

author: xavier60
author_rank: Super Contributor
timestamp: October 19, 2017, 10:01:31 pm
content: Quote from: GonzoTheGreat on October 19, 2017, 07:25:05 pmUsually that kind of power supply circuit uses an IC that is also intended for conventional flyback designs which use an isolating transformer.Are you certain that the circuit is drawn correctly?

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 20, 2017, 08:49:15 pm
content: Quote from: xavier60 on October 19, 2017, 10:01:31 pmYes, I verified it again.I even took apart the inductor. It consists of 2 windings (25 turns and 103 turns) connected in series.

author: ebclr
author_rank: Super Contributor
timestamp: October 20, 2017, 09:19:10 pm
content: https://www.richtek.com/assets/product_file/RT9013/DS9013-10.pdf

author: xavier60
author_rank: Super Contributor
timestamp: October 20, 2017, 10:16:28 pm
content: Quote from: ebclr on October 20, 2017, 09:19:10 pmIs that the correct link?

author: ebclr
author_rank: Super Contributor
timestamp: October 21, 2017, 01:57:59 am
content: Just opened nowhttps://www.richtek.com/assets/product_file/RT9013/DS9013-10.pdf

author: Circlotron
author_rank: Super Contributor
timestamp: October 21, 2017, 02:12:20 am
content: The way it is drawn is difficult to follow but it looks like some kind of non-isolated buck regulator with the ground reference point of the control ic flapping up and down with the inductor input voltage.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 23, 2017, 04:25:39 pm
content: Going out on a limb: Perhaps the power MOSFET and this Mystery IC came in some kind of a kit from the same manufacturer.So if we could identify who made this MOSFET, maybe that will also point to the manufacturer of this IC.The logo on the MOSFET does not resemble Signetics nor Siliconix. Any ideas who made it ?See the photo attached below.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 23, 2017, 04:32:31 pm
content: Quote from: Circlotron on October 21, 2017, 02:12:20 amIndeed it is a non-isolated constant current regulator (320mA, 50-80VDC out). I admit, it was my assumption that Pin2 is the GND.What would be a better way of drawing the schematic?P.S.Indeed, the scope shows the Pin2 flapping at 24kHz.

author: iainwhite
author_rank: Unknown
timestamp: October 23, 2017, 05:05:42 pm
content: Re: the MOSFETI did a google search for D5N50 and came up with a SiHD5N50D Mosfet from Vishay Siliconix - do you think that is it? Could it be an earlier logo for Siliconix ??Update:I put the phrase "Siliconix C1EH" into google and it pointed me to a Texas Instruments step down TPS64203 regulatorMaybe i'm running off in the wrong direction here ??

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 25, 2017, 01:41:00 am
content: Quote from: iainwhite on October 23, 2017, 05:05:42 pmI don't think so because if you zoom-in the photo of the blown MOSFET, its number appears to be ?SD5N50 since there is a fragment of the letter "S" in front of the "D".Quote from: iainwhite on October 23, 2017, 05:05:42 pmThe entire device is maximum 2 years old ...and I don't think that DPAK cases existed 15 years ago.Quote from: iainwhite on October 23, 2017, 05:05:42 pmThat was a good try but the pinout is different and I cannot find the string "C1EH" anywhere in the TPS64203 datasheet.Thanks for trying

author: iainwhite
author_rank: Unknown
timestamp: October 25, 2017, 02:40:41 pm
content: Quote from: GonzoTheGreat on October 25, 2017, 01:41:00 amLooks like I let my creative thinking run away too much!

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 25, 2017, 03:22:10 pm
content: Quote from: ebclr on October 21, 2017, 01:57:59 amIsn't this a linear regulator ?

author: Anatoly
author_rank: Newbie
timestamp: November 26, 2017, 04:45:43 pm
content: Hi, your chip looks very similar to chinese SF6761Shttp://www.sifirsttech.com/admin/datasheet/SF6761S_DS_final_v1.0.pdfHowever, if your diagram is drawn right: 1). You must solder this chip upside down 2) This chip has positive current sense voltage. Must say, I've never seen modern pwm chips with negative CS, so it looks really very strange to me... Maybe you can post photos of your PCB so we can see this wonder?...

author: vuko
author_rank: Newbie
timestamp: August 24, 2018, 08:55:23 am
content: I was looking for chip with similar markings and found this:http://www.icpower.com.cn/UploadFile/Soft/SD6900%20datasheet_1.4.pdf

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: December 05, 2018, 04:07:49 pm
content: Quote from: vuko on August 24, 2018, 08:55:23 amThis one seems to be a match !What were your markings ?

author: vuko
author_rank: Newbie
timestamp: January 17, 2019, 06:50:01 pm
content: Markings are: "e2eh 9l21". I have ended replacing it with SQ6211. It has similar pinout but with dimming input.