Help to identify--PIC or what? - Page 1
Forum section: electronics / general

author: kenny
author_rank: Newbie
timestamp: June 07, 2017, 01:14:07 pm
content: Howdy, i de-potted and trying to reverse a Panasonic EVSE battery charger control board to figure out how it works. Everything can be found except this 20-pin controller chip (IC1) located in the upper left quadrant marked "284K557". i thought it might be a PIC but haven't found one with that label.There are traces to a 3-pin programming header from pins 3,7 & 8. The chip sends a 1 kHz PWM signal with a duty-cycle that determines charging-current out on pin 18. It senses the voltage level of this signal back thru a circuit to pin 17.Has anyone seen or know what this chip is? Thanks for looking and any help, kenny

author: free_electron
author_rank: Super Contributor
timestamp: June 07, 2017, 02:04:16 pm
content: most likely a seiko or sanyo part , judging by the font used ...

author: DBecker
author_rank: Frequent Contributor
timestamp: June 07, 2017, 04:42:46 pm
content: What EVSE is that from?I've reverse engineered a few myself, including most of the ChargePoint models up to the CT4000.You should expect to find circuits for pilot signal generation, AC current sensors for charge current and differential/fault current, voltage monitoring and perhaps ground current injection (to verify that the ground conductor can support fault current).

author: kenny
author_rank: Newbie
timestamp: June 08, 2017, 01:53:51 am
content: That's from a Panasonic Level 1 (120vac) EVSE, which limits the current to about 6 to 8 amps--so charging takes a long time. Hoping to figure out how to adjust it for 12 to 15 amps and cut charging time in half. The relay on the other side of the board are rated 20A, 250 vac, so there should be some margin to tap into.

author: DBecker
author_rank: Frequent Contributor
timestamp: June 12, 2017, 09:33:23 pm
content: Be cautious when increasing the power. Many "20 amp" relays won't support that much current. Compare the typical "20 amp" relay with a 20 amp contactor. The contactor will have much larger.. everything. That's what is needed to continuously support the full rated current for hours, in every condition.What type of relay is used? There is a better chance of operating reliably if it has quick-connect terminals on the top rather than only circuit board pins. Not only is the electrical connection more robust, but the attached wires serve as heatsinks.On the plus side, the relays are for safety isolation only. Most production on-board chargers soft-start and stop drawing current immediately when the connector release is pushed. There should be only minimal make-break contact current.

author: kenny
author_rank: Newbie
timestamp: June 13, 2017, 12:53:19 pm
content: The relays are made by Omron, G4A-1A-PE-AQ19, 12v coil, 20A 250vac contacts.i have all the circuits traced and now drawing up a schematic, but still don't know what processor is being used. It is a ssop 20-pin package running on 5 volts. i've checked fujitsu, renesas, sony, sanyo, nxp, microchip--with no luck. It's probably a specially rolled chip, it looks like the surface was etched and then a new part number added.

author: SL4P
author_rank: Super Contributor
timestamp: June 14, 2017, 05:27:33 am
content: Well, if its as straightforward as you suggest in the first post... Voltage in=PWM out (plus some inputs and sensors), writing ypur own code wouldnt be a big job on tbe cpu of choice.

author: kenny
author_rank: Newbie
timestamp: June 14, 2017, 01:40:14 pm
content: Thank you, that's a good idea--and it may come down to that in the end. SSOP is not easy to dead-bug solder, but it could be done. i'm not ready to give up just yet, it was a lot of work to de-pot the board.Here is a picture with the pin functions labelled. One interesting thing i noticed was the top-to-bottom symmetry or mirror imaging of the functions--could be a clue as a feature of the chip, or just the personality of the designer.Outputs are driving the base of a transistor, inputs are sensing an analog voltage. The programming pins (active low, 10k pullups to Vdd) plus Vdd run to the external 3-pin header (not covered with the black conformal coating).

author: DBecker
author_rank: Frequent Contributor
timestamp: June 23, 2017, 04:41:18 pm
content: There isn't anything magical, or even slightly special, required of an EVSE, so it is most likely a very low cost microcontroller.The only challenging required feature is GFCI, which is better handled by a dedicated circuit. Other features that work better with special circuitry are ground impedance checks and perhaps accurate current/voltage/power monitoring, but these are easily done with existing chips rather than integrated.Panasonic has their own line of microcontrollers. It is rare to see them advertised and I've never known anyone to choose them, but they no doubt sell hundreds of millions in consumer products and have an internal cost of a few cents.

author: Sergeii
author_rank: Newbie
timestamp: January 13, 2019, 10:20:28 am
content: Решили с 284k557 тоже нужна помощь сгорела

author: otedawg
author_rank: Newbie
timestamp: November 03, 2020, 10:03:52 pm
content: I know I'm digging up an old thread, but I hate it when you can't find the answer on one of these.I'm trying to do the same thing as Kenny - trying to reprogram my EVSE. The ground detection ic is from Renesas, so after tons of digging, I found the Renesas R8C package 8-bit microcontroller. Follows the pinout (ish), so I'm going to give it a shot.Pin 3 - ResetPin 7 - VCCPin 8 - MODE - Async half-duplex serial comHave a good one.

author: amyk
author_rank: Super Contributor
timestamp: November 04, 2020, 01:28:11 am
content: I think you got it. Datasheet shows pins line up pretty much exactly:https://www.renesas.com/en-us/doc/products/mpumcu/001/rej03b0144_r8c1a1bds.pdfRenesas has one of the most confusing and illogical part numbering schemes, so I wouldn't be surprised if it was one of those parts.

author: m k
author_rank: Super Contributor
timestamp: November 04, 2020, 03:03:59 pm
content: I'm also voting Renesas.Not many has 'K' in it, what leads away from R8 but rare it's also to have a third one between xtal legs and it seems that nowadays they have 78K and R8 combinations.Unluckily they seem to hide old stuff and some are for internal/important customer use only.https://pdf1.alldatasheet.com/datasheet-pdf/view/412252/RENESAS/R8C-20PIN.htmlI've seen two connector things where other one is multiused.