L5107

Preliminary

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

7 of 8

www.unisonic.com.tw

QW-R125-026.b



POWER TOPOLOGY(Cont.)

Output Over Voltage Protection (OVP)

The UTC L5107 provides an OVP circuitry with a reference value of 1.25V in order to protect the system from an

over voltage fault condition. This OVP point can be programmed through the use of external resistors (R1 and R2 in

Figure 2). This OVP voltage can be calculated using Equation 3:

Eq. (3)

2

2

1

OVP

R

)

R

(R

1.25

V







Current Limit

The UTC L5107 features a current limit protection feature to prevent any current runaway conditions. The current

limit circuitry monitors current on a pulse by pulse basis. It limits the current through the inductor by sensing the

normally until the IS pin reaches 0.45V and it is truncated once again. This will continue until the output load is

decreased.

Eq. (4)



PK_LIMIT

MIN

MAX

L

SW

IN

OUT

CS

I

F

L

D

V

-

V

0.45

R









Slope Compensation

The UTC L5107 requires slope compensation for the peak current mode controller. The UTC L5107 uses an

Eq. (5)





SW

CS

IN

OUT

SLC

F

Α

250

L

R

V

V

R

MIN

MAX











μ