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TPS546C23: TPS546C23 Current Share Question in Two Phase Circuit

Dimon
Prodigy 40 points
Part Number: TPS546C23

Hi;

Could you please tell me how the I-share circuit works in TPS546C23 with 1pin coonection for 2 phase application?

As I understand, both master and slave do the current share/balance.

The I-Share pin should send the current to the other block and also receive that; how do we do that with 1 pin and analog signal?

The circuit is not described in the datasheet.

Thank you.

  • 0
    TI__Expert 4365 points
    Same as previous request. We will look into this tomorrow
  • 0 in reply to Alan Martin
    TI__Guru**** 191445 points
    The ISHARE signal is not actually a current rather it is a voltage proportional to the current of the master device. The slave uses this control voltage to add to the COMP circuit proportional to the current differential between master and slave. the control lop drives this error toward zero. It is explained in section 7.3.10 of the datasheet. The current sharing function of TPS546C23 works internal to the IC. All that is needed is a simple connection between master and slave. It can use one pin, remember both devices share a common ground return.
  • 0 in reply to JohnTucker
    Prodigy 40 points

    Thank you John;

    I understand that. Then, the only part do the current balance is SLAVE? Based on your explain and my understanding:

    _ The master device will be responsible for Voltage control (since the master is the only device that has the external voltage feedback loop and components)

    _ The Slave device will check the voltage proportional to the current of the master device (through I-Share pin) and will be responsible for current balancing and control by changing the COMP.

    Is that correct?

    Thanks;

    Dimon

  • 0 in reply to Dimon
    TI__Prodigy 580 points

    Hi, Dimon,

    In short, the current sharing between Master and Slave devices is achieved through ISHARE connection while the duty cycle information is transferred though VSHARE connection.

    You are right the Master device is responsible for output voltage regulation, which means the voltage feedback loop is active in Master device only. The output of voltage loop error amplifier, which is the control signal for main portion of duty cycle, is transferred to slave device through VSHARE connection.

    Meantime, both Master and Slave device would try drive the ISHARE with a voltage signal proportional to the load current the corresponding device is sourcing through an internal resistor, as a result, the voltage level on the ISHARE voltage is representing the average load current and can be interpreted as reference/command for the current sharing loop.

    Based on the difference between individual load current and this current reference on ISHARE pin, the current sharing loop in both device would add an offset upon the VSHARE voltage and utilize this signal to generate the individual duty-cycle.

    From control point of view, the current sharing between Master and Slave is implemented by two separate current sharing loops in these two devices. Both Master and Slave would adjust the individual load current to reach a equilibrium where there is no error between individual current and the current reference.

    Thanks.

    Best regards,

    Ray Chen

  • 0 in reply to Ray Chen
    Prodigy 40 points
    It make sense; thank you Ray.

    Dimon