PM6685TR View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

PM6685TR

Dual step-down main supply controller with auxilary voltages for notebook system power

STMicroelectronics 

Prev 41 42 43 44 45 46 47 48 49 50 Next

PM6685

Equation 27

Monitoring and protections

RTOT = RESR + Rout

The following condition should be satisfied:

Equation 28

fsw

> k × fZ

=

k

2π × Cout

× RTOT

Where k is a free design parameter greater than 3 and determines the minimum integrator

capacitor value CINT:

Equation 29

CINT

>

gm

2π × ⎜⎛ fsw

⎝k

−

fZ

⎟⎞

⎠

×

Vr

VOUT

In order to ensure stability it must be also verified that:

Equation 30

CINT

>

gm

2π × fZout

×

Vr

VOUT

C must be selected as shown:

Equation 31

C > 5 × CINT

R must be chosen in order to have enough ripple voltage on integrator input:

41/52

Share Link: