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TPS1H100-Q1: About Iout and Vcs

Yuta Nishie
Genius 4955 points
Part Number: TPS1H100-Q1

Tool/software:

Hi,

When Iout=2A, Rcs=1kΩ is set so that Vcs=4V. The current limit is set to 10A (typ) using Internal current limit. The CL pin is directly connected to the GND.

< Question >

1. With the above settings, what is the value of Vcs when Iout exceeds 2A?

In the actual measurement, Vcs=4V to 4.5V when Iout=2A to 2.5A, and Vcs=4.5V when Iout > 2.5A. Is this correct behavior?

2. Before the current limit (10 A) is reached, the value of Vcs exceeds the value of Vcs,H (min). Is this state recognized as a fault output state?

Best Regards,

Nishie

  • +1
    TI__Genius 10225 points

    Hello Nishie, 

    I looks like the RCS needs to be lowered for this case. Here is the equation from the datasheet that uses the same IOUT value that you are operating with. In addition to this if the IOUT was to be increased to 2.5 A this would lower the RCS to 600 ohms. 

    BR, 

    Alan

  • 0 in reply to Alan Whitehead
    Genius 4955 points

    Hi Alan-san,

    Thank you for your support.

    Could you tell me the reason for calculating by substituting 3V for Vcs?

    Also, with the constant setting I asked, is there a possibility that Vcs becomes Vcs,h when Iout is over 2A? It is assumed that Vcs is saturated when Iout flows over 2A, but is it possible to distinguish Vcs,h from saturated voltage?

    The output current in normal use is 0A-4A, and we would like to accurately detect the current between 0A and 2A.

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Genius 10225 points

    Hello Nishie, 

    In order to keep the 2-A nominal current in the 0- to 3-V range the 3 was used as a substitute for VCS in the above equation. 

    Yes the Vcs and Vcs,h can overlap if the Rcs is not sized correctly, using the equation below the IOUT should be about 20% more the maximum load current to account for the ADC accuracy.

    So for this application RCS = (4 * 500) / 2.4

    Best, 

    Alan