Technical enquri

The best way to disable the IC is to pull the EN/UV pin low with a transistor. This will disable the switching of the device.

Z. Cochrane

Dear sir

pls foward this mail along with ckt.

dear sir

thank for ur repaly. But i have som doubt remaining. so for clering this i here attach the ckt diagram for ur reference. pls chek it give us the advice.

regrds

Jijin

Technical asstant
usha electronics systems
Kerala, India

To turn off the device, install a NPN transistor with the collector connected with the EN/UV pin and the emitter to the Source pin (this transistor is in parallel with the OPTO transistor). Biasing the base of the transistor will turn the device off.

Z. Cochrane

Dear Sir,

We got a LED driver circuit from your site,its title is "High Efficiency (≥85%), High Power Factor(>0.9) 15 W T8 Isolated LED Driver Using LinkSwitchTM-PH LNK406EG"
It contains above 0.9 power factor, input working voltage range is 90-265V and a output of 50V , 0.3A using LNK406EG Ic. And we got another circuit using TNY278PN that I send it earlier.

Can u pls told me that which circuit is more suitable in LED streetlight application our line voltage is 230v ac @ 50Hz. In line voltage may contain a lot of fluctuations, so we must want a input protection circuits.

And our requirements for input parameter are

Applying input voltage - 100 to 300V AC
Required input THD - <20%
Required input PF - >0.9

Required output parameters
We want to develop 12W, 36W, & 72W automatic LED streetlight using
1W,2W or 3W LEDs.

we want it to operate it automatically, ie night on & day off . I think it is possible to shutdown these Ic's . So kindly help us how to shutdown these Ic using external ckt. we would like to operate it with a LDR. And can u told me that where we get the samples of Ic's. Kindly consider this as my request.

regrds
Jijin
Technical assistant
usha electronics systems
Kerala, India

I would recommend using a LNK405 or LNK406 for the 12 Watt application. The LNK406 will have higher efficiency than the LNK405, but the LNK405 costs less. I would recommend using the LNK409 for the 36 Watt application. Our largest LinkSwitch PH device is the LNK409. It can support up to 50 Watts. For your 70 Watt application, I would recommend using two 36 Watt designs.

You can shut down the LinkSwitch PH by applying 200 uA into the V pin. You can bias this pull up off of the Bypass pin.

You can order samples from our website or Digikey carries our products. I would also recommend downloading our free design software to help you design with LinkSwitch PH.

Z. Cochrane

Dear Sir,
we want to buy some samples of LNK 408. how can we get? How Can we pay the amount to you ? Also we do another circuit using ur TNY 264 now we want to buy it from u directly. we mainly used it as an control PCBs in FTL. In our local market we cant get enough quantity and the price is too high.

Regards
Jijin

Technical asstant
usha electronics systems
Kerala, India

Please contact your nearest PI sales office. in PI website main menu go to Buy. You will find where to buy our products.

Dear sir,
We in the application note of TNY 264P can u pls tel function of R2, C3, D6.In that circuit can we replace D6 1N4937 to UF 4007?

Regards,
JIJIN

These components are the drain snubber. This prevents the drain voltage from going too high due to the transformer's leakage inductance. As long as the voltage rating, forward current and reverse recovery time is as good or better, then it is OK to use. In your case, the UF4007 will work fine.

Z. Cochrane

Dear sir,
we got a circuit of 12V using TNY 264P, can u pls tell me any drawback or any complaint in this circuit. In this circuit transformer & IC is heated we add a load. Can u pls help me if any mistake in transformer winding or other. We also want to add a automatic section in this circuit (ie dusk to dawn control) using LDR. We use it to drive a 12V relay.

Regards
JIJIN

You will need to look at the drain current using a current probe and look at the drain voltage. The measurements must be made with an oscilloscope. Make sure that when the drain conducts, the output winding is not conducting. This is proper operation for a flyback design. Also make sure that the transformer is not saturating. Looking at the drain current for any curvature in the current ramp (when the drain is conducting). If the current curves up, the transformer is saturating. The current ramp should be straight.

Z. Cochrane

You will need to look at the drain current using a current probe and look at the drain voltage. The measurements must be made with an oscilloscope. Make sure that when the drain conducts, the output winding is not conducting. This is proper operation for a flyback design. Also make sure that the transformer is not saturating. Looking at the drain current for any curvature in the current ramp (when the drain is conducting). If the current curves up, the transformer is saturating. The current ramp should be straight.

Z. Cochrane

You will need to look at the drain current using a current probe and look at the drain voltage. The measurements must be made with an oscilloscope. Make sure that when the drain conducts, the output winding is not conducting. This is proper operation for a flyback design. Also make sure that the transformer is not saturating. Looking at the drain current for any curvature in the current ramp (when the drain is conducting). If the current curves up, the transformer is saturating. The current ramp should be straight.

Z. Cochrane

Dear Sir,
We want to add an automatic section using LDR, so can u pls tell me is it possible to shutdown the Ic TNY 294P. If it is, How can it be possible?

Regards
JIJIN

Tinyswitch can be disabled by pulling the EN/UV pin low. You can use a transistor or optocoupler to sink 240 uA out of this pin.

Z. Cochrane

Dear sir,
can you pls tell me that you mean that 240 uA or 240 uV
Regards,
JIJIN

Dear sir,
can you pls tell me that you mean that 240 uA or 240 uV. If a transistor is add in between the optocoupler and Pin no 4 (ie EN/UV), if any complaint in the Ic during the transistor is in OFF stage?
Regards,
JIJIN

You will need to place the transistor is in parallel with the optocoupler transistor. The EN/UV pin has a 240 uA current source. If you bias the transistor to sink at least 240 uA, then the device will stop switching. A simple way is to connect the collector to the EN/UV pin, the emitter to the source pin and the base is driven through a resistor to your shutdown signal. I would suggest you bias the base with at least 25 uA to ensure that the pin is pulled to less than 0.5 volt.

Z. Cochrane

Dear Sir,

      We  gave single phase power supply to the one input of 3-phase power converter circuit.
The circuit output voltage is 3.3V at 150mA but  output voltage generate 2.2 volt.
 
 We verified  feedback resister value is correct.
Give to the correct solution for 3.3V output voltage circuit.
 
Used Part No: LNK306DG-TL
 
Description   :IC OFFLINE SWIT OCP 8SOP
 
 
Thanks & Regards,


  Saravanakumar.N

  G.K Power Expertise
  chennai-16

Thanks for Posting your question into forum. Could you please send us the schematic so that we can understand what are you trying to do? If you are using TL431 , make sure the reference voltage of TL431 is as per the datasheet. What's the output voltage when it is no load? Whats your input specifications?

Regards,

PI-KSAN