UCC1806

UCC2806

UCC3806

Low Power, Dual Output, Current Mode PWM Controller

FEATURES

• BiCMOS Version of UC1846 Families

• 1.4mA Maximum Operating Current

• 100µA Maximum Startup Current

• 1.0A Peak Output Current

• 125nsec Circuit Delay

• Easier Parallelability

• Improved Benefits of Current Mode

Control

DESCRIPTION

The UCC1806 family of BiCMOS PWM controllers offers exceptionally im-

proved performance with a familiar architecture. With the same block dia-

gram and pinout of the popular UC1846 series, the UCC1806 line features

increased switching frequency capability while greatly reducing the bias

current used within the device. With a typical startup current of 50

µA and a

well defined voltage threshold for turn-on, these devices are favored for ap-

plications ranging from off-line power supplies to battery operated portable

equipment. Dual high current, FET driving outputs and a fast current sense

loop further enhance device versatility.

All the benefits of current mode control including simpler loop closing, volt-

age feed-forward, parallelability with current sharing, pulse-by-pulse current

limiting, and push-pull symmetry correction are readily achievable with the

UCC1806 series.

(continued)

10

7

3

8

SYNC

9

RT

4.4V

1.5V

OSC

LO

CT

3X

4

5

EA

6

120

µA

1

S

1

QB

R

S

2

13

VC

11

AOUT

14

BOUT

12

GND

T

Q

QB

SHUTDOWN

LOCK OUT

S

1

Q

R

S

2

200

µA

Q

R

S

16

200k

1.00V

0.35V

Q

R

S

CURRENT LIMIT

RESTART

UNDER VOLTAGE LOCKOUT

15

15V

5.1V

REFERENCE

REGULATOR

REFERENCE LOW

4.25V

2

CURLIM

SHUTDOWN

VREF

0.5V

–

+

COMP

7.0V

7.5V

CS–

CS+

NI

INV

COMP

VIN

BLOCK DIAGRAM

SLUS272A - FEBRUARY 2000

UDG-99035

application

INFO

available

Pin numbers refer to DIL-16 package.