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TPS65185: Clarification on datasheet

Mitchell
Expert 4915 points
Part Number: TPS65185

Hi Team,

My question is actually in regards to the TPS651851, not TPS65185. For some reason the part number field box does not recognize the TPS651851 as a valid part number.

From the data sheet it shows 4 input rails which the system should provide to the PMIC--

  1. VIN pin 10 for Internal LDO and VCOM 
  2. VIN3P3 pin 45 for EPD panel 
  3. VB-SW pin 40 for DCDC1 
  4. VIN_P pin 24 for DCDC2 

Based off this, our questions are:

  1. In what domain is this IO voltage that is max voltage is 3.6V while the rest of the device seemingly can operate to 6V? 
  2. Recommended Operating Conditions for VB_SW (DCDC1) are not shown, are they the same as VIN_P (DCDC2)?
  3. Since 3.6V is also the max voltage for our EPD controller, what is the mechanism for operating the I/O signals at 3V3 yet the PMIC at, say, 5V to improve PMIC performance?

I am assuming that in table 7.3, VIN_P should have said VB_SW and that the VIN3P3 should have been 3.6 and that the I/O signalling is as referenced by VIN3P3 but I don't want to make any assumptions here.

Thanks,
Mitchell

  • 0
    TI__Genius 10490 points

    Hi Mitchell,

    To clarify, VIN, VIN_P, and VIN3P3 are defined as inputs. VB_SW is defined as an output in the pin functions table. Where are you seeing it described as an input? It is separated from the input voltage by the boost inductor. 

    1. For optimal size, speed, and other performance metrics, only certain blocks of the device are designed to operate with up to 6 V. The logic I/O and charge pump circuits are designed for operation with different supplies internally generated from the main supply (or supplies). These internal supply voltages will vary depending on the block. For example, the logic blocks can be supplied with around 3.3 V to support 3.3 V logic systems, while the charge pump feedback pins can be designed around a 1 V reference. 
    2. VB_SW is the positive boost converter switch node. It is defined as an output pin, so only the absolute maximum ratings (-0.3 V to 20 V) are specified and shown in Table 7.1 of the datasheet. The operating conditions of this pin will be different from VIN_P/DCDC2 since they are converting different voltages.
    3. As mentioned above, the input voltages are stepped down internally for the digital core and logic I/O. 

    Table 7.3 is correct, VIN, VIN_P, VIN3P3 are the only pins designed to connect directly to an externally generated input voltage like a battery or another power supply. VIN3P3 is used for the load switch and it's related circuitry, as shown in the functional block diagram:

    Thanks,

    Gerard