LTC2977 datasheet(103/138 Pages) AD

103 / 138 page

LTM4664A

103

Rev. 0

For more information www.analog.com

PMBus COMMAND DETAILS

IOUT_OC_FAULT_LIMIT

The IOUT_OC_FAULT_LIMIT command sets the value of the peak output current limit, in Amperes. When the controller

is in current limit, the overcurrent detector will indicate an overcurrent fault condition. The following table lists the

progammable peak output current limit value in mV between ISENSE+ and ISENSE–. The actual value of current limit is

(ISENSE+ – ISENSE–)/MFR_IOUT_CAL_GAIN in Amperes.

MFR_PWM_MODE[7] = 1b,

High Current Range (mV)

ILPEAK (A)

IOUT (A)

MFR_PWM_MODE[7] = 0b,

Use ILIM Low Range Low

Current Range (mV)

ILPEAK (A)

IOUT (A)

18.86

Not Needed

10.48

29.9

23.9

20.42

Not Needed

11.34

32.4

26.4

21.14

Not Needed

11.74*

33.54

27.54

22.27

Not Needed

12.37

35.3

29.3

23.41

Not Needed

13.01**

37.1

31.1

24.55

Not Needed

13.64

38.9

32.9

25.68

Not Needed

14.27

40.8

34.8

26.82

Not Needed

14.90

42.6

36.6

* = Recommended for 25A Current Limit Plus Some Headroom

** = Recommended for 30A Current Limit Plus Some Headroom for Up to 1.2V Output

Note: This is the peak of the current waveform. The READ_IOUT command returns the average current. The peak output

current limits are adjusted with temperature based on the MFR_IOUT_CAL_GAIN_TC using the equation:

Peak Current Limit = MFR_IOUT_CAL_GAIN • (1 + MFR_IOUT_CAL_GAIN_TC • (READ_TEMPERTURE_1-27.0)).

The LTM4664A automatically converts currents to the appropriate internal bit value.

The IOUT range is set with bit 7 of the MFR_PWM_MODE command.

The IOUT_OC_FAULT_LIMIT is ignored during TON_RISE and TOFF_FALL.

If the IOUT_OC_FAULT_LIMIT is exceeded, the device:

• Sets the IOUT bit in the STATUS word

• Sets the IOUT Overcurrent fault bit in the STATUS_IOUT

• Notifies the host by asserting ALERT, unless masked

This command has two data bytes and is formatted in Linear_5s_11s format.

**MFR_PWM_MODE[7]=1 is the high current range for ultra low DCR sensing. This range should be used since these

current threshold values are too large for the LTM4664A.

*Recommended for 35% up above 25A current limit

LTC2977 Datasheet(PDF) 103 Page - Analog Devices

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