Shutting off TOP226
I have a circuit using a TOP226 that works well. I need to be able to shut it off with a logic signal. I know you have JX and HX series that have shutoff function, but I'd like to stay with the TOP226 if it's practical, as we have inventory and the PCB is largely working.
Pls see the attached; can i use the DC line to drive the Control pin as shown in blue? How low a current can i get by with for the control current? (There's a lot more to our circuit than shown here, but i've included the power portion)
If i must change to the HX or JX, please give me an idea of the difference in the two series; without rigorous analysis, they look identical.
This is somewhat urgent as i discovered this need late in the design. I'd appreciate any help you can offer.
Ron
Comments
Worf - thanks. I'm about to light up a TOP256YN in place of the TOP226 in my circuit; I needed a TO-220 pkg for an easy-to-find heatsink. The JX won't be as easy for us.
For on/off control, I'll try to use fig 24 in the HX brochure, viz., ground/open pin X. I guess i can add resistance in series w/ the X pin if i want to modify curr lim. Zero ohms on X pin is normall curr lim; pin X open is TOP off.
For the differences between HX and JX see page 19 of the below link
http://www.powerint.com/sites/default/files/product-docs/topjx_family_datasheet.pdf
One way to shut down the controller is bringing the control voltage down to zero. But you have to do it fast enough to do not bring up your output voltage.