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TPS7H2140-SEP: Trip-off time for LCL application

Mouhameth TALL
Prodigy 20 points
Part Number: TPS7H2140-SEP
Other Parts Discussed in Thread: TPS7H4011-SEP, TPS7H2140EVM

Tool/software:

Hi,

I am currently working on Latching Current Limiters (LCL) based on the TPS7H2140-SEP for a Power Conditioning & Distribution Unit (PCDU) for a satellite. The input voltage requirement imposed is 22V-34V, whereas I see that the component is rated for up to 32V. My main question concerns the tripping and current limiting response times. Can these timings be controlled at the component level? I don't see where this is mentioned in the datasheet. If it is possible, how can it be implemented? This function is critical for our LCLs.

Another question: If I want the component to operate in auto-retry mode (automatic restart after a trip) or in latch-off mode (requiring a command to restart after a trip), how do I configure it? These are standard functions for LCLs.

Thanks in advance for your support.

Best regards,

Mouhameth

  • +1
    TI__Expert 5321 points

    Hi Mouhameth,

    While 34V is still within the range of the absolute maximum ratings, I must caution that this is above the recommended operating voltage range of the device. In addition, the SEE testing for this device was only performed to 32V.

    Addressing your question about the current limit, the TPS7H4011-SEP implements a constant-current limit, where the output current is clamped to the configured current limit, but the output channel is not completely shut off. The "response time" or "tripping time" of the current clamping when current limit is triggered is not configurable on this device.

    Additionally, while there is no auto-retry or latch-off mode for the current limit (the current limit simply releases when the output current demand falls below the configured current limit value) the device does implement these options for thermal shutdown. The THER pin on the device configures if the device will automatically restart after an over temperature event, or if it will require the EN signal to be toggled before enabling again.

    The TPS7H2140-SEP also implements a current sense pin that allows the current on each channel to be sensed (one channel at a time) using an internal current mirror and MUX. This feature can be combined with an external microcontroller (or other circuitry) providing the EN signal to produce additional desired behavior. 

    Additional oscilloscope screenshots showing device functionality can be found in the device datasheet section 9 "Application and Implementation" and in the TPS7H2140EVM user's guide.

    Thanks,

    Andy