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BQ25620: D+ D- with USB MCU?

Nicholas Zambetti
Prodigy 230 points
Part Number: BQ25620

I am implementing the BQ25620, and have two questions about D+ D-

Question 1) There are 22ohm line-termination resistors and ESD protection on D+ D- (see schematic below). Would these interfere with the BQ25620's DCD or BC charger detection?

Question 2) D+ and D- will also be connected to my MCU (not yet in the schematic below). I am planning to disable the MCU's USB interface until the BQ25620 indicates that it is done with detection. Is there any problem with having the D+ and D- connected to both the BQ25620 and my MCU? Generally, how is it recommended to share D+ & D- between the BQ25620 and a USB-capable MCU?

  • 0
    TI__Guru 57831 points

    Hi,

    1. It is possible. 

    2. D+/D- pins are used for USB input current limit detection when VBUS power is plugged in. During the charger input current limit detection process, the host must be able to HIZ D+/D- pins so that D+/D- pins are driven by the charger. If the host is unable to HIZ D+/D- pins, a USB switch is needed to isolate the D+/D- pins of the host and the charger. 

    Thanks,

    Ning.