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TPS26744E-Q1: Power Delivery

Part Number: TPS26744E-Q1
Other Parts Discussed in Thread: TPS65988

Tool/software:

Hi. I need to use dual TPS26744 controller. How to sync both of them to get 4 ports in sync. 

  • Hello,

    Can you please clarify your requirement?  Do you want to synchronize the DCDC clocks, enable power sharing across 4 ports, or something else?

    Thanks,
    Eric

  • Hi, , Total current source should be 5A in all 4 ports.

    Requirement - Input 110V AC 60Hz, AC DC converter 50W ( 2 ) each or 100W ( 1 ) , Power Delivery supports dual type C PD ports (2), All 4 PD ports, 5V/9V/15/20V, even for example 2 devices are connected , both should consume total of 5A, same with 3 devices, all 3 should consume 5A, Voltage will differ based on device battery. 

    Only Source no Sink or DPR is needed

    Need to enable power sharing in all 4 ports

    How to sync PD controllers and Type C PD ports together.

    Hope you got my requirement,

    Thanks

  • I can use another controller as well if this doesn't suits for my application. Please share which one to use and how to synchronize PD controllers as well as PD Ports

  • We don't typically limit the ports by output current.  We limit by power.  For example, it appears you have 100W available power to distribute across 4 ports.  There could be 5V/3A on every port, which sums to 12A, but only 60W.

    To share power between all 4 ports, connect I2C2 of one PD controller to I2C1 of the other PD controller.  I2C2 serves as I2C controller, I2C1 serves as I2C target.

    Regards,
    Eric

  • Yes I agree that we limit by power, Power Sharing you mentioned, how about Type C PD controller, do we have to sync them too for poewr sharing, all 4 ports

    Above reply there can't be 5V/3A in every port coz all ports can't exceed 5A in total. same with 20V/3A

  • Hello Geet. As Eric mentioned, the two PD controllers can be connected via I2C which will enable 4-port power sharing. This will then support a max power limit across all 4 ports that is dynamically adjusted based on the number of ports that will be connected to sinks at any time. Does this clarify the question?

    Regarding the input/output power, from the 110V AC input, what is the DC output voltage in your design (the supply voltage to the 2xTPS's and 4xDC-DC's)? This will then define the max output current of your AC-to-DC converter for a given power.

    In this use case, the TPS26744E-Q1 PD controller power sharing is based on total power of the 4 ports which is configurable - in this example my understanding is that this will be set to a max of 100W total. That means at any time 100W or less is available to output between all 4 ports. If 4 type-C sinks (VBUS = 5V) are connected, each drawing 15W, that will be a total of 4x15W = 60W. With each port consuming 5V/3A.

    If the AC-DC converter is capable of 100W, this should work as expected, correct? Or maybe I misunderstand your application?

  • Hi Eric / Zack,

    Thanks for your feedback.

    First there won't be 4 DC-DC converter as form factor will increase. Only 2 units of 50W converter or 1 unit of100W converter only.

    Second Each port can't carry 3A as total current itself is 5A. So, in case 1 port is taking 5V/3A ( 15W ) so another board can take only 2A suppose 5V/2A(10W) or with 20V device (40W) and rest ports will not charge the device.

  • Hi Geet,

    4 DC/DC converters are required for the proposed system.  Each PD port could have a different voltage, so each needs a DC/DC converter.  So you have:

    Input Voltage AC/DC rectification Common DC Voltage Voltage regulator per PD port Output Voltage
    110V AC 2x50W or 100W supply ?? V Port 1 DCDC VBUS Port 1
    Port 2 DCDC VBUS Port 2
    Port 3 DCDC VBUS Port 3
    Port 4 DCDC VBUS Port 4

    I am still not clear on the current limit requirement.  What causes the bottleneck at 5A?  I would be more worried about power.  For example, option 1 in your attachment shows 2x50W supplies.  Lets use the following scenario:

    Port 1: No load

    Port 2: No load

    Port 3: 20V/2A load (40W)

    Port 4: 20V/2A load (40W)

    Here, I am not violating the 5A output current requirement, but I am drawing far more power than the 50W supply can provide can provide.

    Instead, I suggest we limit sum(Port 3, Port 4)<=50W.  This could mean I have two 5V/3A loads (or 9V/3A + 5V/3A or 15V/2A + 5V/3A, etc).  This violates your total current requirement, but does not violate the power supply's rating.

    Regards,
    Eric

  • Reason of taking 50W 2 units is due to form factor limitation but let's take 100W supply.

    Example you took Port 1: No load

    Port 2: No load

    Port 3: 20V/2A load (40W)

    Port 4: 20V/2A load (40W) Similarly Port 1 - 10W, port 2 - 50W , Port 3 - 7.5W , port 4 - Load ( No Charge or slow charge). 

    Can this be done? 

    What if we don't limit our ports 3 and 4.

    Thanks. 

  • Hello Eric,

    Can we optimize the two DC to DC converter with some discrete logic to get the required power?

  • TPS26744 controller has many functions which can't be used. Can we take TPS65988 going forward , or any other with similar functionality where I2C2 of one PD controller to I2C1 of the other PD controller.  I2C2 serves as I2C controller, I2C1 serves as I2C target. 

  • Hi Geet,

    Do you need an automotive grade device?  TPS65988 is not automotive qualified.

    You need a DCDC converter per-port.  There's not getting around that.  Each of the 4 ports could request a different voltage, so you need a DCDC to supply each one.

    Power is redistributed when a new device attaches to the port or is removed from a port and is highly situational. We are not able to allocate power the way you described above.  We  typically treat all ports as equal.  That is, we allocate the remaining power budget evenly across ports.

    Regards,
    Eric

  • Hi Eric. Our application require non automotive but Automotive works in case there is no option. 4 DC DC occupy cost as well as dimension. Any chance we can use 2 converter instead of 4. Please share any architecture / requirement feasible within our range. Thanks

  • Hi Geet,

    It is not possible to use 2 converters to supply 4 ports.  Each port needs a dedicated converter because the output voltage may be different on each port.

    Example architecture:

    Regards,
    Eric