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bq500212A

Intellectual 475 points

Replies: 2

Views: 782

Hi, could some one tell me what is the IC pin or the concept to reduce the power tranfer with the BQ500212A. I analized TIDA-00334 to have 2w of power instead of 5W of EVB, but I didn't understand how to realize that, I presume through I-SENSE but I am not sure.

Thank.

2 Replies

  • Hello Gianluca Pererle

    Two approaches and be used to limit output power on the bq500212A.

    1.) See TIDA-00415, Diode D3, R13, C15 and R12 form a filter ckt for Pin 1.  This is a coil peak voltage detect circuit that can be used to limit power.  As power out increases the coil voltage will increase this can be used to trip the Peak Det ckt to stop power transfer and trigger a reset.

    2.) The DPL circuit can also be used to limit input power but more design and testing is required.  DPL will use input voltage sensed at pin 46, if this drops below about 600mV the unit will reduce output power.  Output from the current sense amp could be used to monitor input current.  The circuit would use this input to pull down pin 46 when current reaches a predetermined point.

    Also take a look at TIDA-00762 this is another low power TX with fewer external parts.  It does have a current sense amp and DPL feature, same type of circuit could be used.

    Best Regards,

    Bill Johns,  Applications Engineer

    Texas Instruments Inc

    Dallas, Texas

    For more information on Battery Charger Solutions see Link

    Search "FAQ" on E2E Forum for common questions on battery charger solutions. 

  • In reply to Bill Johns:

    Hi Bill, I tried the solution number 1 with some components that I have in my laboratory that are close to that of TIDA-00415 and tried also the idea to decrease the voltage to pin 46 but I have some futher questions:

    - what is the rule to follow for peak detection circuit design, I mean, I have 1.5 V on COMM+ on average with 0.6 Vpp of reaple when the board works as normal operation, when it goes to limit conditions COMM+ voltage has always 1.5V but a reaple of 1.2 V, how can I design the circuit peak detection properly?

    - I think to use a circuit coparator do short pin 46 to ground when voltage on I-SENSE goes over a particular set point, could be?

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