TPS65070: TPS65070 power path manager maximum INPUT

Madhu Wesly said:

1. What is the maximum INPUT supply we can give at AC?? Can I power-up the PMIC with 9V(max)??

 

Realistically, no, the PMIC will not operate as expected if VAC = 9V because the over-voltage protection will prevent 9V from being present on the SYS pin. Since the SYS pin is usually the input voltage to the VINDCDCx pins and these pins are only rated up to 6.3V, it would not be possible to run the system off of a 9V input. 

The maximum input voltage that will not result in an over-voltage condition is specified as 5.8V

Madhu Wesly said:

2. Can anyone of the DCDC regulators in the TPS65070 PMIC supports surge current of 2A with a duration 300msec once in every 5mins??

Here, you want to look at the ILIMF spec for all of the DCDC converters: DCDC2 and DCDC3 will not shut off the FETs until at least 2.1A, so it is possible they would be able to withstand a short surge in load. However, the maximum current through the inductor will be higher than the load current and 300ms will be longer than a single clock cycle. You will need to test this to determine if it will work in your system. The TPS65070EVM-430 could be useful in helping you test this scenario, but you will need to swap out the LPS3015-222ML inductor for one that has a current rating.

Hi Brian Berner,

Thanks for your reply.

- In TPS65070 datasheet, the max input supply given as 17V at VAC, doesn't the power path manager stepdown the input supply and give it to VinDCDCs??

- Could you please suggest me any other TI's PMIC with similar specifications as TPS65070 but supports minimum input AC adapter supply of 9V?? 

Awaiting your reply.

Thanks in advance.

Madhu,

The max input to VAC is 17V, but that simply means it will withstand this voltage without damaging the PMIC. Anything over 5.8V will produce an over-voltage condition and disable the connection from AC-->SYS. Both of these values are shown on page 7 of the TPS65070 datasheet.

I understand this may be confusing terminology, but the Power Path Management (PPM) is consistent across many parts including the TPS65070, TPS65217, and all BQxxxx discrete battery chargers: the PPM simply selects the best path for current to flow to the SYS pin. It can best be described as a Mux to select between AC, USB, and BAT, but it has the additional feature of being able to reverse the direction of the BAT<---->SYS FET and act as an LDO to charge the battery from AC or USB when available. However, since it is not a DC-DC converter, it would be very inefficient to charge a single-cell battery from 9V through an LDO.


The most common way to solve this problem is to use a "pre-regulator", a DC-DC in front of the PMIC that will generate 5V from a higher voltage upstream (9V or 12V). The TPS54424 will work for up to 4-A load current, resulting in 5V*4A = 20W of output power for the PMIC. If your new 5V rail can also be the supply to more components in your system, the TPS64824 deliver up to 8-A load current.

Hi Brian Berner,

Thanks for your suggestion. I will do that.

I have one more doubt please clarify it:

1. Will there be an increment in ripple(or Noise) at output supply when the load takes Surge current of 2A??

2. What will be the efficiency of the DCDC2 converter in the TPS65070 PMIC when the load is taking 2A surge current??

Thanks in advance.

These follow-up questions have been asked in a new thread and I am closing this thread.
e2e.ti.com/.../702546