TPS2HB35-Q1: current-limited threshold

Ivy Jin

Part Number: TPS2HB35-Q1
Other Parts Discussed in Thread: TPS2HB16-Q1

Tool/software:

Hi team,

According the datasheet, if the ILIMx pin is left floating, the device will be set to the default internal current-limited threshold 36A. However, in the customer's actual test, when the ILIMx pin is left floating, the chip was directly broken. (Auto-Retry mode)

The customer did more testing as follows:

1. When RLIMx=3Kohm, the chip was directly broken.

2. When RLIMx=3.9 Kohm, ICL = KCL / RILIM=36A, the chip is not damaged.

Could you please help check below questions? Thank you!

1. Is it normal for the TPS2HB35-Q1 is broken when the ILIMx pin is left floating? This seems to be different from what is described in the datasheet.

2. Could the TPS2HB35-Q1 be able to run reliably over a long period of time at RLIMx=3.9 kOhm？

3. If the customer uses the latch mode, will there be any improvement to this problem?

Regards,

Ivy

3 months ago

0 Patrick Shalton 3 months ago

TI__Mastermind 28420 points

Hi Ivy,

Is there any capacitance on the ILIM pin, parasitic or otherwise? This can cause a delay in the ILIM trip time.

How is the customer testing short to GND? Do they have an AEC Q100-012 setup, or are they just shorting the device to GND with a cable?

Thanks,

Patrick

0 Liang Yao 3 months ago in reply to Patrick Shalton

Prodigy 30 points

vBB=24.5V Output capacitor connected,1000uF . MCU activates the channel. The result is that HSD is faulty: the input and output of HSD are directly short-circuited.

0 Patrick Shalton 3 months ago in reply to Liang Yao

TI__Mastermind 28420 points

Hi Liang,

Can the customer make 2 modifications:

1. Change the 10k GND resistor to 4.7k.

2. Add a 220nF capacitor to the output for transient support. This will quickly provide current to the output during fast short to GND events and protect against ESD events.

Thanks,

Patrick

0 Liang Yao 3 months ago in reply to Patrick Shalton

Prodigy 30 points

1、220nF have always existed，

2、After changing to 4.7K, there are still some failures. Cannot be protected

0 Liang Yao 3 months ago in reply to Patrick Shalton

Prodigy 30 points

If the ILIMx pin cannot left floating,

datasheeet Recommended resistance : 5K~25K

however

140 / 36 = 3.89kΩ OK？？？？

0 Patrick Shalton 3 months ago in reply to Liang Yao

TI__Mastermind 28420 points

Hi Liang,

If the ILIM resistance is outside of 5k-25k, the device will default to the 36A current limit, which is not bounded by min/max limits.

Please use a current limit resistor within 5k-25kOhm, or use TPS2HB16-Q1 if you need a higher max current limit.

Thanks,

Patrick

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TPS2HB35-Q1: current-limited threshold