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BQ51050B: BQ51050B Quiescent Current

B Hofer
Prodigy 20 points
Part Number: BQ51050B
Other Parts Discussed in Thread: TPS22914

Dear E2E community!

Currently we are designing for a customer a device requiring wireless charging and the BQ51050B seems suitable for us. Quiescent current reduction is a key for this application, therefore we have some questions about the specifications in the datasheet (SLUSB42E –JULY 2012–REVISED MARCH 2015):

1. The specified quiescent current is at VBAT=4,2V and from 0°C ≤ TJ ≤ 85°C. Can you provide us with typical values for Tj=25°C and 50°C or do you have further details e.g. diagrams for this parameter?

2. Our device relies solely on wireless charging, so it would be reasonable to connect EN2 to VBAT ("disables wired charging source and wireless power is enabled if present.") However, the internal 200k pull down would lead to a quiescent current of up to 21uA. Does the wireless charging functionality still work if EN2 ist set to GND? Are there other things to consider in this case?

Thanks a lot in advance and kind regards,

B. Hofer

  • 0
    TI__Guru* 75486 points
    To reduce the Quiescent current several customer have used TPS22914 devices to disconnect the charger from battery when charger is disabled. TPS22914 are load switches that will operate at low voltage, package size is 0.78mm X 0.78mm. The device is placed between battery and charger with charger voltage controlling the ON pin.

    1.) Test data for Tj of 25C to 50C is not readily available--I will try to track it down.

    2.) A good solution here would be to Ground AD pin. Low at AD pin will disable wire charging. In this configuration EN2 pin can float with no risk of wired charging being active.