TMS320F2800152-Q1: GPIO max current reliability

Nicolae-Andrei Campean

Hello E2E design support,

What would be the effects by having an current 4mA<Igpio<20mA ? In an automotive application the TMS320F2800152-Q1 drives some small signal mosfets with PWM (100Hz, 100kHz), gate charging current - 7mA (3V3, 470ohm series resistor).

How can i weigh how much will influence this the functionality and reliability of the uC?

Thank you in advance !

over 1 year ago

0 Hareesh Janakiraman over 1 year ago

TI__Guru* 95315 points

As shown in page 58 of www.ti.com/lit/SPRSP68, the max current that can be sourced from a GPIO pin is 4mA. The 20ma number is a absolute max number. As stated in the note(1) of section 6.1, drawing more current than allowed could impact reliability. Unfortunately, the precise way how reliability is impacted cannot be easily determined.

0 Nicolae-Andrei Campean over 1 year ago in reply to Hareesh Janakiraman

Prodigy 10 points

So to be on the reliable zone all the time would be recomended that the peak/mean value of the GIOP sink/sourced current to be smaller then 4mA all the time, right ?

0 Nicolae-Andrei Campean over 1 year ago in reply to Hareesh Janakiraman

Prodigy 10 points

Rephrasing the question, note(1) of section 6.1 applies as well when driving capacitive loads with GPIO?

0 Nicolae-Andrei Campean over 1 year ago in reply to Nicolae-Andrei Campean

Prodigy 10 points

Or what is the maximum capacitive load driving capability of the GPIO's ? Can drive (PWM, 100kHz) a capacity of 100pF ?

0 Hareesh Janakiraman over 1 year ago in reply to Nicolae-Andrei Campean

TI__Guru* 95315 points

I discussed this issue with two experts in-house and their feedback was as follows:

"...We faced such questions in the early days for MOSFET and IGBT drivers due to the majority of drivers demanding peak current exceeding our max current spec. We recommended customers use external buffers. The problem went away due to introduction of drivers that don’t demand such high peak current. We went through a similar journey on driver turn on voltage. It took some time for power semi companies to introduce drivers that works with the 3.3V GPIO output thresholds of our MCU...."

"For any HV switching MOSFET, there has to be a gate driver for source and sinking enough current in order to turn on/off the MOSFET. 4mA may be inadequate to what they need and so the PWM output from C2000 is typically applied through the gate driver".

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TMS320F2800152-Q1: GPIO max current reliability