TPSI3050-Q1: Inquiry About EN Pin Leakage Current

Hello Manoj,

Thank you for reaching out regarding EN pin leakage current on TPSI3050-Q1. 

There is a 1MOhm Pulldown resistor from the EN pin to VSSP that results in a leakage current proportional to the EN pin voltage (Ven/1MOhm) when it is left floating or pulled to a logic level.

In Two-wire mode, the Enable pin currents at startup and steady state for minimum (RPXFR = 7.32 kOhm) and maximum (RPXFR = 20 kOhm) power transfer settings are expressed in this section of the data sheet: 

In Three-wire mode, power is supplied through VDDP and is transferred to the secondary side when the EN is toggled, the datasheet specifies the expected current on VDDP here: 

Please note that in Two-wire mode, power is supplied via the EN pin which then charges the external capacitance attached to VDDP (determines EN pin current) before transferring power to the secondary side (as mentioned in the data sheet):

The team is looking into expected leakage current over the full temperature range and will circle back in 24hrs.

Thank you.

Hussain

Hello Manoj,

Thanks for following up. May you please confirm the required state of the device (Disabled or Enabled) for the expected leakage current? 

Assuming that the device is enabled in 2-wire mode, the maximum current across the full temperature range (-55 C → 150 C) is as follows: 

At Startup:

IEN_START, MAX = 33 mA 

In Steady State:

RPXFR = 7.32 kΩ

IEN, Max = 2.1 mA 

----------------------------

RPXFR = 20 kΩ

IEN, Max = 7.4 mA 

Do note, these values are not guaranteed by TI as they are not in the datasheet. These values should serve as a design reference only.

Thank you.

Best,

Hussain

Hello Manoj,

Thanks for clarifying. We expect the leakage current of EN pin in 3-wire mode to be lower than values mentioned above for 2-wire mode across the operating temperature of the device. 

I have looped in relevant team members on my end to get an answer and will be in touch once we come to a conclusion.

Until then, please note the following expectations for the leakage current in 3-wire mode across temperature range:

Device Disabled:

IEN, Max = Ven/1MOhm → {Ven < VIL_EN}

Device Enabled:

 IEN, Max → pending investigation 

Thank you.

Best,

Hussain

Hello Manoj,

Thank you for your patience as internal team works to simulate the EN pin leakage across temperature.

I have escalated this issue and expect an update early next week. To assist with getting this data as quickly as possible, please feel free to shoot me an email at h-alsahhaf@ti.com.

Best regards,

Hussain