TPS25910 questions about EN and current limit

Hi Xiao,

Please find my response below
1. In case of over current, the device TPS25910 maintains pre-set current limit value till the device goes into Thermal shutdown. TPS25910 has Auto Retry function.
2. It is recommended to use external FET as interface
3. Though we have not tried paralleling on this device but it should be possible. The devices may not share the load equally. When the devices are fully ON, current sharing becomes a simple function of path resistances.

What range of current support you are looking for? and what is your end application?

Best Regards,
Rakesh

Hi Rakesh,

1. Could you please describe its Auto-Retry behavior? there is no info in datasheet.

2. why recommend a FET to control EN? and what does this sentence mean in page7 of datasheet: "Because high impedance pullup and or down resistors are used to reduce current draw, any external FET controlling this pin must be low leakage"?

we may use in I_normal=2A, I_peak=5A or more, Vin=19V ( TPS25610 may be not enough if considering derating). End application is Medical Ultrasound Device.

Thanks.

Hi Xiao,

1) The TPS25910 device operates in power-limit mode during an overload condition and increases the voltage drop
across power switch. The thermal sensor turns off the power switch when the die temperature exceeds 160°C.
Hysteresis is built into the thermal sensor, and the switch turns on after the device has cooled approximately
20°C

2) As mentioned in Page7 of datasheet: ENB is pulled to VIN by a 10-MΩ resistor, pulled to GND by 16.8 MΩ. External FET with high leakage shuts the internal 16.8 MΩ and can ENABLE the device. FET with low leakage would not affect the ENB level.
At higher VIN, the voltage at ENB gets clamp to 7V which cannot be handled by LVCMOS3V3 devices.

Regards,
Rakesh

Hi Rakesh,

2) to choose a FET for controlling EN, how "low" should the leakage be? For example, an ordinary N-MOSFET 2N7002 has drain leakage current of typical=0.01uA and max.=1uA, will this be low enough?

Thanks!

Hi Xiao,

up to 2uA should be fine for 12Vin system. Yes, N-MOSFET 2N7002 can be used. To have better freedom in choosing external FET, configuration like below will help in overcoming the dependency on leakage current.

Regards,

Rakesh

Thanks, Rakesh.