BQ40Z50: CHGFET or DSGFET doesn't turn ON/OFF when triggered from BQStudio

Aji Santoso89

Part Number: BQ40Z50
Other Parts Discussed in Thread: BQSTUDIO

Hi,

I'm here to ask about FET control on hardware. Why DSGFET or CHGFET doesn't turn ON/OFF while triggered from BQStudio ? When i toggled ON CHGFET, XCHG register shows green and CHG red. I measured on Vgate, the voltage is 12.38Volts. When i toggled OFF CHGFET, XCHG register shows red and CHG is green, but the voltage doesn't go down to near 0V. I measured it at 12.20 Volts. And it happened same on DSGFET. What is wrong with my design ? Because of grounding or something else ?

Here i attached my design in ZIP file document.

Kindly Please answer this question.

Thank you.

Best Regards

Aji SantosoBQ40Z50 layout.zip

over 7 years ago

0 Jasper Yi over 7 years ago

TI__Intellectual 1365 points

Hi Aji,
If CHG bit was red and XCHG bit was Green, the gauge FW turned on the CHG FET if you set your color bit High in red and Low in Green.
If you read Operation Status bit registers, you would verify this bits are set to "1" or "0" to make it sure. Vgate voltage should be around 20V when it is turned on. Please, remove your FETs with plugging in charger and then measure Vgate. Is it happening at all boards ?

0 Aji Santoso89 over 7 years ago in reply to Jasper Yi

Prodigy 230 points

Hi Jasper,
I already checked the registers. CHGFET is High and XCHG is Low. Also i had removed my FETs, plug my charger. I measured Vgate is still around the same at around 12.38V when CHGFET high, XCHG low, and 12.20V when CHGFET low, XCHG high. Next, when i connected my load and i toggled DSGFET ON, the registers shows DSGFET high, XDSG low and so on. But i measured Vgate is still around the same at around 12.38V when DSGFET high, XDSG low, and 12.20V when DSGFET low, XDSG high. So what's wrong with my design ?

0 Jasper Yi over 7 years ago in reply to Aji Santoso89

TI__Intellectual 1365 points

Hi Aji,

Please, upload the schematic with pdf format. I wonder there is a short to CHG,DSG pin internally or externally.

0 Aji Santoso89 over 7 years ago in reply to Jasper Yi

Prodigy 230 points

Hi Jasper,

Here is my schematic document in PDF format.Battery gauge Modified 2 rev2.PDF

0 Jasper Yi over 7 years ago in reply to Aji Santoso89

TI__Intellectual 1365 points

Hi Aji,

Does VC4 to VC1 voltage is applied in stable ? Can you communicate with the gauge successfully ? Can you see the pulse on TS1 pin when PACK voltage is applied ? If everything is OK and Vgate(CHG/DSG) pin is 10V, then please switch the IC with EVM to see IC is damaged.

Power management

Power management forum

BQ40Z50: CHGFET or DSGFET doesn't turn ON/OFF when triggered from BQStudio