UC2902: MathCAD tool download

Hi

The UC2902 is an older device. Why does your customer use the UC2902 when the newer UCC29002 is available and has the Mathcad design tool to support design in.

Regards

Peter

Hi Peter

Due to VDD=15V, UC2902 supports 20V and UCC29002 supports 13.5V

Hi user4819061,

The UCC29002 has a better current sense amplifier and it can be used from a 15V supply.

The method is shown in Figure 5 of the data sheet

Regards

John

Hi John,

I am the guy who use UC2902. I read the spec carefully before I chose the Load-Share Controller. I found that the UCC29002 recommended supply is 13.5V(max), and the absolute maximum supply is 15V. I don't know whether it's a good idea to chose the UCC29002 in my design for extended periods. So I chose the UC2902 in my design. Can I still supposed to choose the UCC29002 for my design?

Besides, I am worry about my design, because I use the buck controller and transformer for my supply, the feedback path is long , I am not sure it can work properly. Could you help review my design? Thanks.

BR.
Frank

Hi Frank,
You can use the UCC29002 for voltages much higher than 13.5V if you use the simple NPN driver interface shown in Fig 5 of the data sheet. This drawing is labelled "High Voltage application"
You can see that the emitter ( connected to VADJ ) will have a bias voltage of VBASE-0.7 and VDD will have a bias voltage set by the voltage divider RBIAS1 and RBIAS2. This is how the UCC29002 sees an input of less than 13.5V.
The length of the feedback path may not matter as much as you think. The important path is how the loads are connected. The sensed voltage in each sensing resistor should be an adequate representation of each modules actual current.
I can review your design if you wish to email me
johngriffin@ti.com

Regards
John

Hi John,

Thank you very much. I will send a email to you.

BR.

Frank