L6986 datasheet(34/68 Pages) STMICROELECTRONICS

Part #	L6986

Description	38 V, 2 A synchronous step-down switching regulator with 30 A quiescent current

PDF	68 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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34 / 68 page

Closing the loop

L6986

34/68

DocID025376 Rev 7

Closing the loop

Figure 24. Block diagram of the loop

5.1

GCO(s) control to output transfer function

The accurate control to output transfer function for a buck peak current mode converter can

be written as:

Equation 18

where RLOAD represents the load resistance, gCS the equivalent sensing transconductance

of the current sense circuitry,



p the single pole introduced by the power stage and z the

zero given by the ESR of the output capacitor.

FH(s) accounts the sampling effect performed by the PWM comparator on the output of the

error amplifier that introduces a double pole at one half of the switching frequency.

GCO s



RLOAD gcs



RLOAD TSW



-----------------------------------

mC 1D

–





0.5

–





--------------------------------------------------------------------------------------------------------



------







------





---------------------- FH







L6986 Datasheet(PDF) 34 Page - STMicroelectronics

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