SLUU195 − June 2004
With the chosen inductor described in Inductance Value, (section 4.2, of this document) the following values are used.
•R=19.6 kΩ
•C=10 nF
•RNTC=100 kΩ
•R1=124 kΩ
•R2=22.6 kΩ
VDCR
L
L
DCR
VIN
DCR
R
C
VIN
R
C
VC
VOUT
R1
R2
RNTC
RTHE
UDG−03136
Figure 6. DCR Current Sensing Circuit with Copper Temperature Compensation
4.7Overcurrent Limit Protection
The overcurrent function monitors the voltage level separately on each current sense input and compares it to the voltage on ILIM pin set by the divider from the controller’s reference.
If the threshold of VILIM/2.7 is exceeded, the PWM cycle on the respected phase is terminated. Voltage level on the ILIM pin is determined by (11).
VILIM + 2.7 IPH(max) | RCS; IPH(max) | + IOUT ) | VIN * VOUT | VOUT | (11) | |
2 LOUT | fSW | VIN |
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where
•IPH(max) is the maximum allowable value of the phase current
•RCS is the value of the current sense resistor
12TPS40090
