BQ24075: BQ24075RGTR out of sleep mode

Sripriya Raghavendran

Prodigy 100 points

Part Number: BQ24075

How do I get this chip BQ24075RGTR out of sleep mode?

Ref datasheet: The datasheet http://www.ti.com/lit/ds/symlink/bq24075.pdf

over 5 years ago

0 Raheem over 5 years ago

TI__Mastermind 21590 points

Hello,
You get the device out of sleep mode when VIN > UVLO and VIN(DT).

0 Sripriya Raghavendran over 5 years ago in reply to Raheem

Prodigy 100 points

Hi,
Thank you.
I have a couple follow up questions:
1. Can we configure this chip (BQ24075RGTR) to never go into sleep mode?
2. If not, is there a similar alternate chip you would recommend?
Thanks,
Sripriya

0 Raheem over 5 years ago in reply to Sripriya Raghavendran

TI__Mastermind 21590 points

Sripriya,
Is there any reason you're worried about this feature? The device has VINDPM which tries to maintain the input voltage above 4.5V and reduces the input current to ensure this. Do you expect your input voltage to be in the 3.3V range?

0 Sripriya Raghavendran over 5 years ago in reply to Raheem

Prodigy 100 points

Our power source is a wireless power receiver. It appears that during transient load changes, the input(VIN) to this battery charger IC collapses, causing it to enter sleep as expected. Therefore we suspect this IC puts VBAT (4.16V) on VIN, which appears to contend with the output of the wireless power receiver. This condition persists until the sleep timeout approximately 20mS later when the system restarts. We are hoping to disable sleep mode to test our theory.

0 Raheem over 5 years ago in reply to Sripriya Raghavendran

TI__Mastermind 21590 points

Hello,
There is no way to disable sleep mode on this device. VBAT leaking to VIN is not expected on this device as the Input FET shuts off in sleep mode and there is are backwards facing FETs on he input. Did you try placing a schottky diode on the input to see if VBAT still shows on VIN?

0 Raheem over 5 years ago in reply to Raheem

TI__Mastermind 21590 points

Also can you elaborate on the end equipment for this project and what the planned charge current is.

0 Sripriya Raghavendran over 5 years ago in reply to Raheem

Prodigy 100 points

The data sheet indicates that after 20mS into entering the sleep mode the FET is disconnected. We are concerned about the 20mS duration behavior.

9.4.1 Sleep Mode

When the input is between UVLO and VIN(DT), the device enters sleep mode. "After entering sleep mode for >20

mS the internal FET connection between the IN and OUT pin is disabled"

Please find a scope shot captured from our test.

Ch1 shows the Vin follows Vbat for 20mS then the FET gets turned off.

0 Sripriya Raghavendran over 5 years ago in reply to Raheem

Prodigy 100 points

We set the current to 500mA but host can overwrite it. Its a bar code reader.

0 Raheem over 5 years ago in reply to Sripriya Raghavendran

TI__Mastermind 21590 points

Hello,
Can you try this with a lower VBAT(around 3.2V) and post the scope capture. Also try to connect the anode of the diode you have on /PGOOD to SYSOFF so that the connection to the battery is turned off and let me know what happens. This is done to ensure VIN is absent before going into sleep mode.

0 Raheem over 5 years ago in reply to Raheem

TI__Mastermind 21590 points

Sripriya,
I was able to reproduce this in the lab and you're correct that this is due to the sleep mode of the device. The Input FET waits 20ms before shutting off into sleep mode.

0 Sripriya Raghavendran over 5 years ago in reply to Raheem

Prodigy 100 points

Thank you so much for your help.

In our design, we are powering this TI part with IDTP9027LP which is a Qi WPT receiver.

The IDT chip has a slow response to transient events.

If you have any suggestion how to hold the VIN to TI part when there is a certain demand of current, it would be helpful.

We are right now using capactiors upto 40uF at the VIn node.

We thank you again for your help.

Thanks,

Priya

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BQ24075: BQ24075RGTR out of sleep mode