cancel
Showing results for 
Search instead for 
Did you mean: 

L9663 power limitation on the output of psi5 interface

AMan.1
Associate

Hello,

I have a problem with the l9663 and the output is limited to 9.4V aprox no matter how much I use on it's input(maximum value tried 15V).In the datasheet it states that the transceiver is compatible with psi5 ver 2.x and 1.3.According to the psi5 protocol the transceiver should work between 5 and 11 volts. I tried many configurations of registers but no avail .When I read the status register one (SR1) it indicates an overvoltage on the Vas even though I disabled it using the CHCNT register during the programing phase of the transceiver.

Is the Vas somehow still active and limiting the output of the transceiver or is some other problem at hand?

1 REPLY 1
TEvan.3
Associate II

I'm guessing you're trying to get 10V-12V in order to program a sensor. Probably the NXP ones. The L9663 can't do that. The Over-Voltage detector is always running, can't be disabled and triggers between 8.2V and 8.8V and shuts off the output.

But if you want to get 11V across the sensor (for programming), then just connect its negative pin to a -5.5V supply. Carefully. Expect to blow things up if you get this wrong. You'll probably have to bring it up at 5V and then slowly ramp the negative pin down to the required voltage.