LM5041AMTC/NOPB National Semiconductor, LM5041AMTC/NOPB Datasheet - Page 12

• Manufacturer Part Number: LM5041AMTC/NOPB
• Description: IC CTRLR PWM CASCADED 16TSSOP
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM5041AMTC/NOPB

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 1MHz
• Duty Cycle: 91%
• Voltage - Supply: 15 V ~ 90 V
• Buck: Yes
• Boost: Yes
• Flyback: No
• Inverting: Yes
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-TSSOP
• Frequency-max: 1MHz
• For Use With: LM5041EVAL - BOARD EVALUATION LM5041
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM5041AMTC; *LM5041AMTC/NOPB; LM5041AMTC

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Slope Compensation
The PWM comparator compares the current sense signal to
the voltage at the COMP pin. The output stage of the internal
error amplifier generally drives the COMP pin. At duty cycles
greater than 50 percent, current mode control circuits are
subject to sub-harmonic oscillation. By adding an additional
fixed ramp signal (slope compensation) to the current sense
ramp, oscillations can be avoided. The LM5041A integrates
this slope compensation by buffering the internal oscillator
ramp and summing a current ramp generated by the oscil-
lator internally with the current sense signal. Additional slope
compensation may be provided by increasing the source
impedance of the current sense signal.
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Soft-start and Shutdown
The soft-start feature allows the power converter to gradually
reach the initial steady state operating point, thereby reduc-
ing start-up stresses and surges. At power on, a 10uA cur-
rent is sourced out of the soft-start pin (SS) to charge an
external capacitor. The capacitor voltage will ramp up slowly
and will limit the maximum duty cycle of the buck stage. In
the event of a fault as indicated by V
Under-voltage the output drivers are disabled and the soft-
start capacitor is discharged to 0.7V. When the fault condi-
tion is no longer present, a soft-start sequence will begin
again and buck stage duty cycle will gradually increase as
the soft-start capacitor is charged.
Thermal Protection
Internal Thermal Shutdown circuitry is provided to protect the
integrated circuit in the event that the maximum junction
temperature is exceeded. When activated, typically at 165
degrees Celsius, the controller is forced into a low-power
standby state, disabling the output drivers and the bias
regulator. This feature is provided to prevent catastrophic
failures from accidental device overheating.
CC
Under-voltage, line