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TPS1H200A-Q1: Cascading high side switches in parallel for higher current limit

Ashish Sapkota
Prodigy 20 points
Part Number: TPS1H200A-Q1
Other Parts Discussed in Thread: TPS1HB08-Q1

I am using two TPS1H200AQDGNRQ1 in parallel with 5A current limit setting (ie Rcl= 400ohms for 5A setting) on each to get 10A current limit option.

My input is 40/ 11A power supply and output is connected to a constant current programmable DC load.

If I take a single TPS1H200AQDGNRQ1 and put current limit setting of 3A, it works properly (ie, output turns OFF to 0V when 3.1A is set to programmable DC load)

But, if I take two TPS1H200AQDGNRQ1 and have 5A setting it is only able to current limit 6.5A. I have delay setting of 0.2s.

My question is: 1) Does cascading two current limiter not work to get higher current limit setting?

                         2) How to design 10A current limit setting using high side switches (max voltage=42V)?

                         

  • +1
    TI__Mastermind 32650 points

    Hi Ashish,

    We do not recommend this operation as there is no guarantee that the split of current is going to be exact between the two devices. This means that one device can hit current limit before the other. To support 10A DC, we recommend using a low Ron device like TPS1HB08-Q1. Also note that the internal limit for this device is typical 4.8A with a minimum of 3.5A and a max of 6A. It is not possible to set an external limit that is larger than the internal limit of the device. Therefore, external limits are to be set lower than the minimum internal limit of the device.

    We also do not recommend the use of electronic loads in CC mode. This is because the eload will pull a set amount of current and two schema are competing on what the output voltage are supposed to be (i.e., the internal CL block and the eLoad). Furthermore, the device is not meant to be operated as a current source in DC. The device's current limit capability s to protect the load and supply in the event of a high current event like a short of filling a capacitor. current limitations comes at the cost of power dissipation which can cause the device to turn off due to thermal shutdown.

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    Prodigy 20 points

    Thank you Shreyas for your reply