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TPS65185: Circuit diagram review and power block inquiries

MJ Jeon
Genius 5240 points
Part Number: TPS65185

Hi,

My client company is developing EPD (Electric Paper Display) using TPS651851.

During EPD development, I have a request for a review of the circuit diagram.
(Review of attached circuit diagram)

EPD_PM-IC_SCHEMATIC2020104.pdf

In addition, the EPD power block diagram is attached.
There are Request Contents on pages 5 and 6 of the block diagram.
Please answer your questions.

EPD DISPLY PM IC CONTROL schematic.pptx

[page 5]

1.POWER CONTORL

     EPD PM-IC POWER: It will receive power from system PM-IC(ALL Voltage control)

     Is there no problem? (VSYS=5V)

[page 6]

2. EPD DISPLAY Temperature control

   Can I use the NTC circuit for EPD DISPLAY THERMAL CONTROL?

   Is it programmed to enable NTC control in TPS651851PM-IC?

   Is it possible to I2C control with EPD DRIVER IC?

Thank you.

Regards.

MJ

  • 0
    TI__Mastermind 28340 points

    Thread is assigned to the appropriate apps

  • 0
    TI__Genius 10490 points

    Hi MJ,

    Comments on the schematic:

    • The recommended inverting buck-boost output capacitance (VN OUT) is 3 x 4.7 uF. The schematic currently has 4 x 4.7 uF
    • VEE_DRV nominal capacitor value (C88) should be 10 nF 
    • VEE charge pump only requires 1 x 4.7 uF output capacitor (C91 or C87)
    • VDD charge pump only requires 1 x 4.7 uF output capacitor (C71 or C72)
    • For VGH = 28 V, R129 must be 37 kOhms
    • Technically, pin 49 is denoted PPAD rather than PGND. This avoids confusion since pin 49 should be connected to VN OUT. 

    Regarding your questions:

    1. POWER CONTROL

         EPD PM-IC POWER: It will receive power from system PM-IC(ALL Voltage control)

         Is there no problem? (VSYS=5V)

    3.3 V and V_SYS = 5 V are both acceptable for the TPS651851. I cannot comment on the IT8951 specifications. 

    2. EPD Display Temperature control

       Can I use the NTC circuit for EPD DISPLAY THERMAL CONTROL?

    This NTC can be used, but keep in mind the TPS651851 datasheet NTC specs assume the Murata NCP18XH103F03RB thermistor. 

       Is it programmed to enable NTC control in TPS651851PM-IC?

    The TPS651851 will only measure the NTC temperature when commanded, and generate an interrupt if the for hot/cold temperatures. The controller must decide when to measure the temperature and how to respond to hot/cold events.  

       Is it possible to I2C control with EPD DRIVER IC?

    Yes, TPS651851 temperature monitor settings can be controlled via I2C - please refer to the TMST1 and TMST2 registers in the datasheet.

    Thanks,

    Gerard