JR611 SOIC-8 in bicycle lamp.

Ian Field

unread,

Nov 4, 2015, 1:36:23 PM11/4/15

to

Its a long shot, as its probably a house coded part.

Its a Crivit Sport LED bicycle lamp from the Lidl discount store.

Originally it was the LED that went intermittent, but when a second unit
died I decided I could spare one to experiment on.

Suitable LED parts are on order from Ebay, but I thought I'd have a go at
upgrading it with a switch mode current control. The circuit is ready, but I
need to identify the "glue logic" type stuff on the PCB.

The on/off button is a simple pushbutton, the latching is done
electronically. It also has a low battery warning LED - these features would
be nice to retain, but I need a little help identifying the stuff on the
board.

Thanks.

N_Cook

unread,

Nov 4, 2015, 1:57:06 PM11/4/15

to

Have you isolated and powered each power LED from a bench ps?

Ian Field

unread,

Nov 4, 2015, 2:21:25 PM11/4/15

to

"N_Cook" <div...@tcp.co.uk> wrote in message
news:n1dk9m$5ks$1...@dont-email.me...

Replacing the LED chip fixed the intermittent fault, so that pretty much
eliminates the circuit on the PCB.

But While I'm working on it - I'd like to upgrade it with SMPSU technology.

N_Cook

unread,

Nov 4, 2015, 4:08:46 PM11/4/15

to

Adding some extra heatsinking would not go amiss

Ian Field

unread,

Nov 4, 2015, 4:14:23 PM11/4/15

to

"N_Cook" <div...@tcp.co.uk> wrote in message

news:n1ds0h$5s5$1...@dont-email.me...

The whole point is to reduce dissipation - not disguise it.

The LED rating is no less than 1W and the bicycle lamp specification only
claims 0.6W - the LED barely gets warm.

whit3rd

unread,

Nov 4, 2015, 5:48:15 PM11/4/15

to

On Wednesday, November 4, 2015 at 11:21:25 AM UTC-8, Ian Field wrote:
> "N_Cook" <div...@tcp.co.uk> wrote in message
> news:n1dk9m$5ks$1...@dont-email.me...
> > On 04/11/2015 18:36, Ian Field wrote:
> >> Its a long shot, as its probably a house coded part.
> >>
> >> Its a Crivit Sport LED bicycle lamp from the Lidl discount store.

...

> >> Suitable LED parts are on order from Ebay, but I thought I'd have a go
> >> at upgrading it with a switch mode current control.

> Replacing the LED chip fixed the intermittent fault, so that pretty much
> eliminates the circuit on the PCB.

I'd worry about the light distribution from a replacement LED; an eBay
item usually doesn't have a good angular distribution specification...

> But While I'm working on it - I'd like to upgrade it with SMPSU technology.

There are some chips that do this; generally, though, it's going to be a small-outline
surface mount part, and will only work from a limited voltage input range.
This is a typical such part:
<http://www.micrel.com/_PDF/mic3289.pdf>
which, as I read it, is suitable for three alkaline cells in series (4.5V nominal).

If you are going to have a switchmode supply, it's most efficient to boost voltage
(the switches and diode have lower losses at lower current) and use multiple LEDs
in series.

Ian Field

unread,

Nov 5, 2015, 2:29:31 PM11/5/15

to

"whit3rd" <whi...@gmail.com> wrote in message
news:30e74932-cb49-4afe...@googlegroups.com...

It'd look pretty funny with multiple reflectors to fit over the multiple
LEDs - and I'd have to scrap a lot of bicycle lights to get them.

The modified buck I'm using puts the LED in series with charging the
inductor - and the catch diode gives it another bite of the cherry.