Part: TPS65132W
issue: the negative output = -2.1V (expected -5.4V)
1. measured input = 4.5V
2. measure positive output = 5.4v, ok
3. measured CFLY1 and CFLY2, need your help to check below.
4. meausre inductor, need your help to check
5. tried to set ENP and ENN = low, both positive and negative output = 0V.
The VNEG load circuit -> TPS7A30 - > 4 * OPA810.
1. I removed TPS7A30, the output of VNEG = -5.4V
2. I connected input pin and output pin of TPS7A30 pad with 10ohm resistor, the VNEG still -5.4V and works fine.
3. I measured another end of 10ohm resistor is -5.2V, so, calculate the current is 20mA. It doesn't exceed TPS65132 limit, I don't know why issue happen with TPS7A30.
You can see from above schematic. The TPS65132W goes up first, and then TPS7A30 enable, and then go to amplifer.
1) first, I didn't do any I2C communcation. So it's the default mode. Issue happens
2) I also tried use I2c to set 80mA mode, the issue still there.
3) I removed TPS7a30, short in and and output of TPS7A30, it works.
So from the test, it seems TPS7A30 caused this issue. But why? Should adjust NR/SS capacitor value?
Please review below schematic.
M5V4 is connected to TPS65132 VNEG.
M5VA are providing power to 4 pcs * OPA810 circuit.
Please see attached PDF for details.power issue.pdf
