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TPS1HB08-Q1: Switch off of the ILIM.

Mark Philip Felipe
Genius 9705 points
Part Number: TPS1HB08-Q1
Other Parts Discussed in Thread: TPS1HA08-Q1

Hi Team, seeking some clarification.

1. On the application resport "How To Drive Inductive, Capacitive, and Lighting Loads With Smart High Side Switches" and it provided an idea to use HSS for capacitive loading. HSS will manage capacitive loading by limiting the output current to ILIM and the current stays at that value until the load capacitor is fully charged.

Looking at your TPS1HB08-Q1 and Sec. 9.3.1.2 of datasheet says that the switch will turn off if ILIM is reached. How will TPS1HB08-Q1 handle capacitive loads if it will turn off the switch at ILIM?

2. Fig. 36 says that pin LATCH is tied to ground. Does this mean "directly tied to ground" or "tied to ground via RPROT"?

Thank you.

Regards,

Mark

  • 0
    TI__Mastermind 25055 points

    Hello Mark,

    For #1, for our high side switches we have two different methods of current limiting: 

    • Shutting off immediately when current limit is hit
    • Clamping the current when the current limit is hit and keep limiting current until a thermal shutdown occurs

    The TPS1HB08-Q1 is a device where the device immediately shuts off when the current limit is hit. In order to use this part to charge a capacitor, you have to set the current limit high enough so that the initial inrush doesn't trigger the current limit. The F version of the TPS1HB08-Q1 has a static current limit of 94A that would be the right fit for this application. If you are looking for a current clamp device (that are usually more suitable for capacitor charging), an alternative device would be the TPS1HA08-Q1.

    For #2, for reverse polarity protection you should have it pulled to ground with a 10k RPROT resistor. If you have a diode on the input rail that would block reverse current, you can get rid of the RPROT resistor and tied it directly to ground.