Help identifier component 3 pins TO-92 chip

Q

Quim 14 years ago

Hello

It is one chip mounted in a 3 pins transistor package. Only have marqued in the package the reference numbers: 004. Num. reference: 004 Package type TO-92

3 pins It is installed in one head light for controller the current for the led. He alone with only one resistor of 1 Ohm generates and run at 500Khz controlling the current and voltage. Also power up the voltage. The condenser it is aditional component and does not internene in the operation for generate Images:

formatting link

Any information for to find oany datashed or manufacturer will be welcomed

Regards

--- Posted via news://freenews.netfront.net/ - Complaints to snipped-for-privacy@netfront.net

Vote

F

Franc Zabkar 14 years ago

On Fri, 20 Apr 2012 14:26:57 +0200, "Quim" put finger to keyboard and composed:

Can you supply a direct link to the images, without the popups, banners, ads, etc?

- Franc Zabkar

Please remove one 'i' from my address when replying by email.

Vote

Q

Quim 14 years ago

formatting link

Regards

"Franc Zabkar" escribió en el mensaje news: snipped-for-privacy@4ax.com...

--- Posted via news://freenews.netfront.net/ - Complaints to snipped-for-privacy@netfront.net

Vote

F

Franc Zabkar 14 years ago

On Mon, 23 Apr 2012 12:13:49 +0200, "Quim" put finger to keyboard and composed:

The only switchmode device in a TO-92 package that I managed to find was this one:

formatting link

However, it doesn't look anything like yours. Its sense resistor is internal to the package. Moreover, I would have expected a coil somewhere in the circuit.

It may help us if you could draw a circuit diagram.

- Franc Zabkar

Please remove one 'i' from my address when replying by email.

Vote

Q

Quim 14 years ago

Many thanks Franc I seee that works directly at mains voltage this supertex driver, it is interesting

The circuit :

formatting link

Not have any coil, I think that surely the cables themselves serve as inductance at this frequence 500khz.

Regards

"Franc Zabkar" escribió en el mensaje news: snipped-for-privacy@4ax.com...

--- Posted via news://freenews.netfront.net/ - Complaints to snipped-for-privacy@netfront.net

Vote

F

Franc Zabkar 14 years ago

On Tue, 24 Apr 2012 01:21:57 +0200, "Quim" put finger to keyboard and composed:

inductance

If your circuit is correctly drawn, then I suspect that the component that you have identified as a 1 ohm resistor may in fact be an inductor.

According to the IC's output waveform, if the component were indeed a

1 ohm resistor, then it would be passing 3A current pulses. If the duty cycle were 50%, then the power dissipation in the resistor would be 4.5W. I don't believe any designer would be silly enough to waste this much energy in a battery powered torch. Moreover, I doubt that a TO-92 package would be robust enough for that kind of continuous current rating.

Otherwise, if the component were indeed an inductor, then your circuit would look like a boost converter, with the IC incorporating a PWM controller and an N-channel MOSFET, possibly with current sensing as well. In this case I suspect that your torch may be just as bright using two 1.2V NiMH or NiCd cells, or maybe even a single cell.

- Franc Zabkar

Please remove one 'i' from my address when replying by email.

Vote

Q

Quim 14 years ago

Yes, yo're right, I have disambled other time the head lamp, unsoldered this resistor, and Ok, it is one inductor, the tipical as one resistor 1/4W with the body a litle green. I measured it and indicate 0,012mH, really are brown, brown, black, 11uH.

Yes, the current and voltage is estabilized within certain limits. I see the limit down are in the input 1,33v for to work well, and the output are 2,7vpp in the waveform, and the led ligths. Input Volts dc - output to the led, waveform voltage zero to peak

3 - 3,2 2,5 - 3,1 2 - 2,9 1,5 - 2,8 1,33 - 2,7 1 - waveform not square and I can't syncronize.

Regards

"Franc Zabkar" escribió en el mensaje news: snipped-for-privacy@4ax.com...

--- Posted via news://freenews.netfront.net/ - Complaints to snipped-for-privacy@netfront.net

Vote

F

Franc Zabkar 14 years ago

On Wed, 25 Apr 2012 17:35:27 +0200, "Quim" put finger to keyboard and composed:

and

in

In retrospect we could have estimated the value of the inductor from your first measurements.

Your 1W LED would have a rating of about 300mA at 3.2V.

The voltage across the inductor would be given by ...

V = L . dI/dt

So dI = V . dt / L

Assuming a 50% duty cycle at 500kHz, then dt = 1 usec.

So dI = 3 . 1E-6 / 11E-6 = 270mA

AISI, your "004" device probably has an internal current setting of around 350mA. I still haven't managed to identify it, though. :-(

- Franc Zabkar

Please remove one 'i' from my address when replying by email.

Vote

Q

Quim 14 years ago

Very well the formulas and the calculatios.

"Franc Zabkar" escribió en el mensaje news: snipped-for-privacy@4ax.com...

--- Posted via news://freenews.netfront.net/ - Complaints to snipped-for-privacy@netfront.net

Vote

Help identifier component 3 pins TO-92 chip

Join the Discussion

Didn't find your answer?