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UCC2808 Overcurrent Threshold Tolerance

Blake Ma
Intellectual 955 points

Hi,

Here I got a question about the overcurrent threshold of UCC2808 from customer. Here is his testing result:

@ Room Temperature:

No.

0009

0011

0012

0013

0015

Overload current

1250mA

1290mA

1230mA

1200mA

1300mA

@ 65 degree:

No.

0009

0011

0012

0013

0015

Overload current

1180mA

1220mA

1170mA

1150mA

1240mA

@ -15 degree: 

No.

0009

0011

0012

0013

0015

Overload current

1260mA

1290mA

1230mA

1190mA

1290mA

My questions are:

(1) Is the above testing result meet with the tolerance of CS threshold?

(2) What is the CS threshold tolerance of UCC2808?

(3) How much will the temperature influence this tolerance?

Waiting for the response... Thanks very much!

  • 0
    TI__Mastermind 31580 points

    Hi Blake,

    Is the customer making these measurements on the power supply? If they are using the power supply please note that other component values in circuit will be varying with temperaure as well. The biggest influence on the over load current threshold measurements is likely to be the inductance of the main transformer which can vary with temeprature as well.

    To determine the contribution of the UCC2808 CS threshold tolerance to the measured values, the customer should test the UCC2808 open loop and use a very well controlled DC voltage to drive the CS pin and measure any change in the CS pin threshold in that setup against temperature.

    The CS pin threshold varition in the datasheet is 0.7V to 0.8V from -40C to 85C.

    Regards

    Peter