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.

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.

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.

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

"N_Cook" wrote in message
...
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.

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.

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

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.

On 04/11/2015 19:21, Ian Field wrote:


"N_Cook" wrote in message
...
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.

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.

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

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.

Adding some extra heatsinking would not go amiss

"N_Cook" wrote in message
...
On 04/11/2015 19:21, Ian Field wrote:


"N_Cook" wrote in message
...
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.

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.

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

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.

Adding some extra heatsinking would not go amiss

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.

On Wednesday, November 4, 2015 at 11:21:25 AM UTC-8, Ian Field wrote:
"N_Cook" wrote in message
...
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.

"whit3rd" wrote in message
...
On Wednesday, November 4, 2015 at 11:21:25 AM UTC-8, Ian Field wrote:
"N_Cook" wrote in message
...
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.

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.