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Power Path Charger - Part Suggestion

Borislau Jevic
Prodigy 205 points
Other Parts Discussed in Thread: TPS2540, TPS2041B, BQ24030, TUSB8040, TUSB2036, BQ24038
Hi,
 
I wanted to suggest a new part for the power path family. My suggestion is the following:
 
Multi-cell charger. Can charge one, two, three or four cells.
 
Pin selectable for Li-Ion/ Li- Pol and LiFePO4
 
Has two separate input paths, one USB (or x2 for a total of 1 Ah) the other wall charger.

Edit:
VIN for USB is 4.5-6.5v. This is due to that some people might use USB "chargers" that actually output 6v+. I have come across a couple of these a couple of years ago.
VIN for Charger to be 4.5v - 18v since some people when they use 12v chargers, they may actually output up to 18v. Protected against up to 24v. For the smaller packages, maybe up to 12v (power good), and also have an extra pin to indicate for Over voltage. I have not included that in the "diagramme" below. (End of Edit)
 
Has an on-board USB controller to request appropriate current, less external parts. This controller can check to request 100 mAh  or 500mAh, without the user having to select a pin for charging current, and also controls the inrush current. Like incorporating an TPS204xB / TPS205xB with USB negotiation.
 
If 500 mAh available, then each battery gets charged at 120 mAh each if four batteries as not to exceed the 500 mAh limit, 225 mAh if two batteries or 450 mAh if one battery attached.
 
If connected to the adaptor pin, then there can be an Isel pin for selecting the charge current up to 2 Ah max of which will give 500 mAh for each battery, of which will also be the limit per battery as to not overheat unprotected batteries.
 
Batteries in the system can be in series, or independent, not //. If in series, then each battery can be attached individually. between the positive and negative of each pole.
 
Batteries are attached in independent pin pairs of the charger, Batt1+ & Batt1 GRND + NTC1 ... Batt4+ & Batt4 GRND + NTC4.
If NTC not used, it can be connected to ground.
 
Charger will see how many batteries are connected to each input, and adjust available current.
 
The part will also balance the charging of each battery independently.
 
Has the following outputs:
 
LED drivers:
Pre-conditioning/ Deeply depleted battery
Normal Charge/ Full Rate
Finishing/Top-up/ Re-charge
Finish/Ready.
Power Good
USB Low current indicator LED if only using 100mAh
USB Power Good.
 
Two Bi-Color LED’s to report fault with battery. Each LED is for two batteries, or another version can have independent LED’s for each battery.
 
Power Path (LDO):
User selectable:
3.3v or 4.4v + 6v when using one battery
3.3v or 4.4v + 12v when using two batteries.
3.3v or 4.4v + 15v when using three batteries.
3.3v or 4.4v + 24v when using four batteries.
 
To select voltage: 2 pin select
If pin select for Vout1 is V+, then 3.3v
If pin select for Vout1 is V - then it is 4.4v
If pin select for Vout2 is V - then it is the maximum for that part dependant on amount of batteries connected.
If pin select for Vout2 is V+, then it is disabled and all current is available for Vout1.
 
The 3.3v / 4.4v can be current limited to 250mA dependant on Vout2.
 
Enable/Disable pin for charger.
 
Can work as an LDO if no battery is present.
 
TMR – User selectable.
 
Current detect, if the piece determines there is not enough current from the adaptor, and it is also connected to USB, then it will supplement from the USB port to reach 500 mAh on each output.
 
USB2 connection, can also be used as a OTG (On The Go) to supply power to other devices, when USB1 is not connected. Pin Selectable.
 
Can be in TSSOP or QFN package or W-DIP
 
Pins can be logically organised to left side and right side.
 
1    ADAPTOR IN     |----------|    Vout1 = 3.3v or 4.4v
2   USB 1 IN+         |----------|    Vout2 = 6v / 12v / 15v / 24v
3    USB 1 DATA      |----------|    Batt4+
4    USB 1 DATA      |----------|    Batt4 NTC
5    GROUND           |----------|    Batt4-
6    USB 2 IN +       |----------|    Batt3+
7    USB 2 DATA      |----------|    Batt3 NTC
8    USB 2 DATA      |----------|    Batt3-
9    USB PowerGood |----------|    Batt2+
10   STAT1 OUT       |----------|    Batt2 NTC
11    STAT2 OUT      |----------|    Batt2-
12    STAT3 OUT      |----------|    Batt1+
13    STAT4 OUT      |----------|    Batt1 NTC
14    B.FAULT 1 & 2  |----------|    Batt1-
15    B.FAULT 2 & 3  |----------|    I sel 
16    BATT CH Select|----------|    Sleep
17    Power Good     |----------|    Timer  
18    USB2 OTG Slct |----------|    USB Low current indicator LED
 
The “BATT CH Select” is for the Li-Ion/Polymer and LiFePO4. Connects to Vcc or Vdd.
 
This device can be highly integrated, so it will need just a few basic parts externally like filter/transient caps (ceramic) . No need for uH coils, fets, OR-Diode etc etc.
 
I hope someone from designing can have a look and advise if this will be considered to be made.
 
Maybe 2 versions can be made, 2 batteries and 4 batteries.

Others are welcome to add to this idea for a highly integrated part.

Edit: This part can also be used to charge protected batteries as well as unprotected.
Edit2: Maybe instead of USB-OTG, it can be made in to a 1port hub? with limit to 100mAh, if it is charging the batteries.

Regards,
Boris
  • TI__Guru 56650 points

    Thank you for posting your suggestion on the e2e forum.

    It seems that the IC put gas gauge and charger IC together. It also supports wide input voltage range. So, it has to be a switching charger. I didn't see any pin to connect to inductor. From Pin1 to Pin 9 for input source, it seems too many pin counts for the input.

  • in reply to Wang5577
    Prodigy 205 points
    Hello Wang,
     
    A few more pins will be needed to be added to the design, but not many. It was a rough draft.
     
    Actually I was thinking more of a marriage of the TPS2540(A)/1,  bq24030, TPS2041B & TUSB2036/TUSB8040 all in one.
     
    Strictly speaking, for it to be classed as a hub, a minimum of two downstreams are required, in that case pins 6 - 9 will be changed to DP1&2 and DM1&2.
     
    There will need to be a couple of more pins maybe added.
    When the part is AC or other source powered, then the TPS254x will be used as a USB battery charger only.
    Else if it is connected using USB - hence the two inputs that I have noticed on a few designs - then it
     
    Having had a look at p7 PDF for TPS254x, it shows 2.7v & 2v of which would give all power / more than 500mA (I think it was 1 Amp). This would be ok, for when the part is powered from the bus or AC. Having an option to select 2v & 2v instead of the 2.7v & 2v for a charging port when the IC is working from battery would give 500 mAh for charging according to the Apple scheme. Have found this out from a couple of websites that opened “emergency portable battery chargers” for Apple products.
     
    I do not see the need for an inductor. The reason I mention this, is that I am basing the design of existing parts that do not need one. 
     
    Correction for suggestion: Can have the batteries // too, as to increase current output for usage. End user can have this as a pin option. If V+ then //, if V- then series.
     
    bullet point version:
     
    From bq2403x series:
    Two inputs: AC & USB -p1,
    TS: NTC Thermistor Temp x4 -p21
    Iset 1&2 : Depending on design, it can be omitted (Iset2 for usb), if enumeration is enabled.
    Psel: p13-p15
    USB PG / AC PG: p9
    CE: p25
    VBSEL: Can be used for 4.1v or 4.2 when in Li-Ion/Li-Pol instead of 4.2/4.36 that is used for bq24038 p2 &
    TMR : p23
    Variation:
    VOUT1 pin select: User selectable. As per original bq2403x series, can be 4.4v or 6v. Addition of 3.3v. Pin select was not shown in original layout.
    As a suggestion: If pin select for Vout1 is V+, then 3.3v, If pin select for Vout1 is V - then it is 4.4v else if left floating 3.3v
    VOUT2 pin select: If V+ then maximum voltage and batteries are considered "in series". If V-, then Vout2 has same voltate as VOUT1 and batteries are considered //.
    For “pin 16” above, V+ can be LiFePO4, V- can be Li-Ion/Li-Pol and if left floating Ni-Mh.
    Maybe add in the errata that if Ni-Mh is to be used, it would need either 3 or 4 batteries, so as the VOUT1 would have enough voltage for the boost and would not be available for VOUT2 and it will divert to VOUT1.
    ----------
     
    From TUSB2036/TUSB8040/TPS2540:
    From the TUSB2036 & TUSB8040 part:
     
    Implementing a 2(or 3) port hub, incorporating USB 3.0.
    Can be with or without Serial EEPROM interface.
    Would need clock input, etc
     
     
    From the TPS2540:
    BC1.2
    CTL1 – CTL3
    I(SHORT) ILIM0 ILIM1 ILIM_SEL : p4 & p9
    The power supply would be limited to 500 mA if running on batteries.
     
    I hope I have cleared a few things up.
     
    As for this part, of which I think you might have been referring to for an inductor:
    User selectable:
    3.3v or 4.4v + 6v when using one battery
    3.3v or 4.4v + 12v when using two batteries.
    3.3v or 4.4v + 15v when using three batteries.
    3.3v or 4.4v + 24v when using four batteries.
    Then to simplify the design, it can be a fixed 12v or 15v for VOUT2. So there will not be a need for an inductor and extra circuitry.
     
    This can be used in mobile devices that have high capacity re-chargeable batteries and can be used to charge mobile phones and other accessories and also be a portable hub.
     
    This would normally involve either 3 or 4 hi capacity Ni-Mh, AA batteries are now at 3,000 mAh (in series), or LiFePO4 AA size or 2660 etc that start from about 600 mAh to 1500 mAh for AA to 3000 mAh, Li-Ion 18650’s up to 4000 mAh  etc not to mention the prismatic varieties.
     
    A couple of ideas where this can be used:
     
    Torch that use large batteries, can also be used to charge a phone and also be a USB hub for security guards.
     
    Using a prismatic battery, low profile usb hub with a charger. Ladies can use to take with them in their purses. Can have an integrated card reader.
     
    Portable Audio Amp. It uses very little power, can charge the source if portable, like an IpXX(pod, phone, pad etc).
     
    List can go on.

    I hope I clarified most of your question and future ones too.
  • in reply to Borislau Jevic
    Prodigy 205 points

     

     

     

    A load balance circuit would also be needed to maximise battery life.

    Also a  low batt indicator, dependant on chemistry, it would warn the end user when he needs to recharge or to stop charging another device if his power is becoming low.

    This would work as follows:

    Depending on chemistry, since each battery is attached separately, it would have its own low voltage reference.

    Regards,
    Boris

  • in reply to Borislau Jevic
    TI__Guru 56650 points

    In TI, several groups are working on customer designs that integrated charger IC. Would you give me your email address? I will forward your post to them and copy you. So, you can discuss it with them directly.