UC3825B: UC3825B

Aniket Band

Part Number: UC3825B
Other Parts Discussed in Thread: UC3825

Dear Sir/Madam,

Greeting from Micropower!!!

We are happy to introduce ourselves as a leading manufacturer of SMPS brand “Micro Power” catering to various industrial applications in “Electronics and Surveillance” and “Industrial Automation”.

Please visit our website www.micropower-india.com

We are developing one new product for which we have used TI make UC3825BN PWM controller

But we are facing problem in problem with PWM controller.

Actually PWM controller not even started.

We did not got VCC at PWM, it will drop the internal start up VCC given by start up resistors.

We have then gave external VCC then PWM controller started but then also we didn't got the voltage value at soft start pin. no 8.

So can you please guide us in proper way.

Thanks & Regards,

Aniket Band

Head, R & D Department,

Sanstar Microsystems Pvt. Ltd.

EL-15, Electronics Zone,

M.I.D.C Hingna Road,

Nagpur-440016

+91 96079 70446 / +91 80078 77425

Web: www.micropower-india.com

An ISO 9001:2015 certified company!

over 6 years ago

0 Peter Meaney over 6 years ago

TI__Mastermind 31580 points

Hi Aniket,

Can you share your schematic so we can see how the controller is connected and the value of the components around the PWM controller?

Thanks

Peter

0 Aniket Band over 6 years ago in reply to Peter Meaney

Prodigy 30 points

6443.Schematic.pdf

0 Aniket Band over 6 years ago in reply to Aniket Band

Prodigy 30 points

Waiting for your valuable response.

0 Peter Meaney over 6 years ago in reply to Aniket Band

TI__Mastermind 31580 points

Hi Aniket,

Sorry for the very late reply, just looking at this now.

Peter

0 Peter Meaney over 6 years ago in reply to Peter Meaney

TI__Mastermind 31580 points

Hi Aniket,

I thought I had already replied to this but for some reason the post was never updated.

The Vcc is supplied through two series 150k resistors into a 10uF cap. Can you check the Vcc on start-up it may be discharged quickly before the output voltage can come into regulation. The Vcc will also need another supply source, like an aux winding from the transformer to keep the Vcc cap charged when the power stage is running as the UC3825 will consume 10 to 20mA of bias current which cannot the supplied through the 300K of resistance connected to Vin.

Regards

Peter

0 Peter Meaney over 6 years ago in reply to Peter Meaney

TI__Mastermind 31580 points

Hi Aniket,

If you have no more questions I will close this post. Please open a new post if you have more questions.

Regards

Peter

Power management

Power management forum

UC3825B: UC3825B