BQ40Z80: PRES Pin Hall effect sensor and DC-DC

ThomasP

Part Number: BQ40Z80
Other Parts Discussed in Thread: DRV5032, , LMZM23601

Hello,

We use a Hall effect sensor (DRV5032FBDBZT) to detect if the battery is plugged in the System.

Is it possible to connect the Output of the Sensor to the PRES pin?
And the Vcc of the DRV5032 to the intern LDO 1,8V from the BQ40Z80?
If yes, at which output is 1.8V?

We also use a DC-DC 3,3V (LMZM23601) for a MCU, Bluetooth and some LED.
Now I would like to control the Enable from DC-DC via the BQ40z80.

BQ40z80 (Aktiv) -> EN on
BQ40z80 (Sleep) -> EN on
BQ40z80 (Ship) -> EN off

Could you please help me to config the Output Pin to Control the LMZM23601?
Which output should I use and how do I configure it?

Thank you very much!
Thomas

over 5 years ago

0 Wyatt Keller over 5 years ago

TI__Guru** 105760 points

Hello Thomas,

I'm not sure of the capabilities of the hall effect sensor, but if it is able to drive the PRES pin low to indicate the battery is present it should work.

The bq40z80 has an internal LDO, it doesn't have any access to the outside, it is a very low current regulator.

To configure one of the GPIO pins for your application you will need to follow the procedure in section 13.2 in the TRM: https://www.ti.com/lit/ug/sluubt5b/sluubt5b.pdf?ts=1592939043651&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ40Z80

This section goes through an example of setting up a GPIO pin.

Sincerely,

Wyatt Keller

0 ThomasP over 5 years ago in reply to Wyatt Keller

Prodigy 60 points

Hello Wyatt,

Many thanks for your response.

At the Datasheet on page 4 (Number 17) https://www.ti.com/lit/ds/symlink/bq40z80.pdf?ts=1592943625994

PRES: Connect to host to detect system present in put for a removable battery pack. Do not pullup this pin.
If the battery not plugged in the System i have 3,3V on the PRES pin from the Hall Sensor. Is this ok?

For the configuration of the GPIO pins which bit would you recommend to me to show the Active/Sleep/Ship Status?

At Active and Sleep the GPIO should HIGH
At Ship the GPIO should LOW

Thomas

0 Wyatt Keller over 5 years ago in reply to ThomasP

TI__Guru** 105760 points

Hello Thomas,

Yes that could be an issue if it's driving it high, you may need some other circuitry to block that voltage.

I'm actually not sure if the GPIO pins stay active in sleep mode, let me check and let you know. I think they are but I will double check, you should be able to use the sleep bit in operation status A to determine what mode you're in.

Sincerely,

Wyatt Keller

Power management

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BQ40Z80: PRES Pin Hall effect sensor and DC-DC