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BQ25173: Schematics review request (BQ25173)

Grady Lee
Expert 2935 points
Part Number: BQ25173

Hi, TI expert

There is a request for a schematic review from a customer. (BQ25173 applied)

Application is an integrated remote control, not using batteries, but USB charging (using Super-Cap) RCU (Remote Control Unit).

Is there anything in the circuit that needs to be modified?

Please review the overall schematics.

[ Attach the Schematics below ]

3771.Schematics (ECO-RCU)_220103.pdf

Please check. Thank you.

  • +1
    TI__Guru 65836 points

    Hello

    The BQ5173 circuit looks OK:

    1.) Charge current is set to 800mA

    2.) Regulation voltage is set to 1.6V

    Note -- /PG and FB max voltage is 5.5V, no problems with this circuit with OUT at 1.6V.  

    Any area of the circuit you are concerned with?

  • 0 in reply to Bill Johns
    Expert 2935 points

    Hi, Bill

    The customer has an additional question.

    BQ25173 Fixed some applied circuits.

    /PG Pin is used to detect USB power.

    - USB power input → /PG pin LOW
    - No USB input → /PG pin HIGH

    Q1) Is there any problem with using the circuit?

    Q2) If the /CE pin is left floating, does the current consumption always consume 0.45~0.6mA?

           If the current is consumed even when the USB power is not connected, it seems that the /CE pin needs to be controlled.

    please check.

    [ Attach the Schematics below ]

    MOVON_BQ25173.pdf

    Please check. Thank you.

  • +1 in reply to Grady Lee
    TI__Mastermind 19195 points

    Hi Grady,

    Some feedback on the schematic,

    1. recommend min 1uF for IN and OUT cap. 
    2. We can guarantee the 0.45-.6mA rating for the test conditions we have listed. For lower current consumption best to pull /CE high with host to disable IC when charging not needed.
    3. Customer may want to consider using higher value resistors for R42 / R43. When adapter is disconnected the FB divider network would consume 1.6V/590 Ohm = 2.7mA. For lowest iq my recommendation would be R42 + R43 = 900kohm, just do not exceed 1Mohm. They can also have PG pin  as the GND connection in the feedback divider to minimize iq for Vreg < 5V.

    Best regards,

    Nick