Max current draw from vsyspwr

[Romsub]

Hiya, 

I was wondering if someone is aware of the maximum current that can be drawn by the daughter board ? It is recommended we use 1.8v (unless kernel modifications are made) but I cant find any information on the max current draw. I was also unable to find the datasheet for MAXIM 77596 IC (only the product brief). 

Cheers

Rams 

[Jacob Postman]

Hi Rams,

The short answer is 600mA on SYS1 and 300mA on V2P9, limited by the board-to-board connector (2 pins for SYS1, 1 pin for V2P9). If you pull near these limits though your board will probably clock down or enter a thermal shutdown pretty quick.

The longer answer: You have two options for supplying the daughterboard with power. In both cases you will be limited by the connector current capacity for peak current. The board-to-board connector (DF40C-30DP-0.4V(51)) is rated for 300mA per pin.

1. SYS1 (2 pins, 600mA) - is the main system power node that supplies all the other regulators and is basically the output of the battery after it passes through the pmic's fuel gauge.

This should only be limited by the connector current rating of 300mA per pin. 2 pins are available so 600mA is the max.

This is generally what I would suggest if you want to put your own voltage regulator on the daughterboard, as it is present even when the imx6sl is off and V2P9 is disabled. For instance sensor applications where you want to shut down the application processor and leave the daughterboard running.

2. V2P9 - The regulator supplying V2P9 (BUCK6) is rated for 800mA, but the connector is only rated for 300mA per pin.

Cheers,

Jacob

--
You received this message because you are subscribed to the Google Groups ">warpx.io" group.
To unsubscribe from this group and stop receiving emails from it, send an email to warpx+unsubscribe@googlegroups.com.
To post to this group, send email to wa...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/warpx/194ef64b-b07f-4279-a52a-b117da0abbda%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Romsub]

Hi Jacob, 

Many thanks for the detailed answer. That is just the information we needed. 

Cheers

Rams 

On Monday, 13 March 2017 07:34:48 UTC, Jacob wrote:

Hi Rams,

The short answer is 600mA on SYS1 and 300mA on V2P9, limited by the board-to-board connector (2 pins for SYS1, 1 pin for V2P9). If you pull near these limits though your board will probably clock down or enter a thermal shutdown pretty quick.

The longer answer: You have two options for supplying the daughterboard with power. In both cases you will be limited by the connector current capacity for peak current. The board-to-board connector (DF40C-30DP-0.4V(51)) is rated for 300mA per pin.

1. SYS1 (2 pins, 600mA) - is the main system power node that supplies all the other regulators and is basically the output of the battery after it passes through the pmic's fuel gauge.

This should only be limited by the connector current rating of 300mA per pin. 2 pins are available so 600mA is the max.

This is generally what I would suggest if you want to put your own voltage regulator on the daughterboard, as it is present even when the imx6sl is off and V2P9 is disabled. For instance sensor applications where you want to shut down the application processor and leave the daughterboard running.

2. V2P9 - The regulator supplying V2P9 (BUCK6) is rated for 800mA, but the connector is only rated for 300mA per pin.

Cheers,

Jacob

On Sat, Mar 11, 2017 at 6:40 AM, Romsub <ramy...@gmail.com> wrote:

Hiya, 

I was wondering if someone is aware of the maximum current that can be drawn by the daughter board ? It is recommended we use 1.8v (unless kernel modifications are made) but I cant find any information on the max current draw. I was also unable to find the datasheet for MAXIM 77596 IC (only the product brief). 

Cheers

Rams 

--
You received this message because you are subscribed to the Google Groups ">warpx.io" group.

To unsubscribe from this group and stop receiving emails from it, send an email to warpx+un...@googlegroups.com.

[Romsub]

Hiya, 

I have a follow up question on the VSYS_PWR.  The daughter board design quick start document says "A high efficiency switching regulator to generate 1.8V from VSYS_PWR is recommended." and we are measuring 4.13 Volts between the SYS1 and GND ports of the interposer. Putting these two things together, is it correct to expect the VSYS_PWR to be 4.13 Volts and a switching regulator has to be used to bring this to 1.8v for the components in the daughter board ? 

Cheers

Rams 

On Monday, 13 March 2017 07:34:48 UTC, Jacob wrote:

Hi Rams,

The short answer is 600mA on SYS1 and 300mA on V2P9, limited by the board-to-board connector (2 pins for SYS1, 1 pin for V2P9). If you pull near these limits though your board will probably clock down or enter a thermal shutdown pretty quick.

The longer answer: You have two options for supplying the daughterboard with power. In both cases you will be limited by the connector current capacity for peak current. The board-to-board connector (DF40C-30DP-0.4V(51)) is rated for 300mA per pin.

1. SYS1 (2 pins, 600mA) - is the main system power node that supplies all the other regulators and is basically the output of the battery after it passes through the pmic's fuel gauge.

This should only be limited by the connector current rating of 300mA per pin. 2 pins are available so 600mA is the max.

This is generally what I would suggest if you want to put your own voltage regulator on the daughterboard, as it is present even when the imx6sl is off and V2P9 is disabled. For instance sensor applications where you want to shut down the application processor and leave the daughterboard running.

2. V2P9 - The regulator supplying V2P9 (BUCK6) is rated for 800mA, but the connector is only rated for 300mA per pin.

Cheers,

Jacob

On Sat, Mar 11, 2017 at 6:40 AM, Romsub <ramy...@gmail.com> wrote:

Hiya, 

I was wondering if someone is aware of the maximum current that can be drawn by the daughter board ? It is recommended we use 1.8v (unless kernel modifications are made) but I cant find any information on the max current draw. I was also unable to find the datasheet for MAXIM 77596 IC (only the product brief). 

Cheers

Rams 

--
You received this message because you are subscribed to the Google Groups ">warpx.io" group.

To unsubscribe from this group and stop receiving emails from it, send an email to warpx+un...@googlegroups.com.

[Jacob Postman]

Hi Rams,

The VSYS_POWER is unregulated and will mirror the battery voltage so will vary between ~3.3V and 4.2V depending on the battery voltage and state of the charger input. If there is no battery connected, it should float near 4.2V.

In order to have a regulated voltage supply on the daughterboard that will remain on when the imx6sl power rails are disabled, you will want to add a regulator to pull power from VSYS_PWR.

The recommendation of 1.8V for this is really based on two factors:

1. the default configuration of the uart voltage that is dropped down to the daugherboard through the board-to-board connector is 1.8V

2. A lower supply voltage is desired where possible in the system to minimize power consumption

If, on the other hand, you don't intend to turn off the mainboard and have the daughterboard continue running, you can pull directly from the V2P9 supply that is dropped to the daugherboard.

This supply voltage (really all the supply voltages on the mainboard) is set by the PMIC and is adjustable. The range of valid values for correct board function is 2.9V-3.3V.

All of the logic level signals (GPIO, SPI, I2C, etc) that are dropped to the daughterboard are can be configured to either the high (V2P9) or low (V1P8) voltage domains by adjusting the LVE bit in the pad control register from the device tree.

Cheers,

Jacob

To unsubscribe from this group and stop receiving emails from it, send an email to warpx+unsubscribe@googlegroups.com.

To post to this group, send email to wa...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/warpx/093865ba-60c6-42cc-8d8b-0d88f6ee0223%40googlegroups.com.

[Romsub]

Hi Jacob, 

Thanks again for the quick and clear answer on the voltage issue. This is very helpful for us to proceed with the daughterboard design. 

Cheers

Rams 

Jacob