UTCUC3842A/3843A LINEARINTEGRATEDCIRCUIT

4

QW-R103-002,A

ERROR AMPLIFIER CONFIGURATION

2

1

0.5mA

2.5V

Zf

Zi

Error amplifier can source or sink up to 0.5mA

CURRENT SENSE CIRCUIT

5

3

1

2R

R1V

C

Rs

R

Is

Error

Amplifier

Current Sense

Comparator

Peak current (Is) determined by the formula:

Ismax=10V/Rs.

A small RC filter be required to suppress switch transients.

SLOPE COMPENSATION

8

4

3

Isense

R1

R2

Rsense

C

RT

CT

A fraction of the oscillator ramp can be resistively summed with the current sense signal to provide slope

compensation for converts requiring duty cycles over 50%.Note that capacitor C, forms a filter with R2 to suppress

the leading edge switch spikes.