UCC1895

UCC2895

UCC3895

DESCRIPTION

The UCC3895 is a phase shift PWM controller that implements control of a

full-bridge power stage by phase shifting the switching of one half-bridge

with respect to the other. It allows constant frequency pulse-width modula-

tion in conjunction with resonant zero-voltage switching to provide high effi-

ciency at high frequencies. The part can be used either as a voltage mode

or current mode controller.

While the UCC3895 maintains the functionality of the UC3875/6/7/8 family

and UC3879, it improves on that controller family with additional features

such as enhanced control logic, adaptive delay set, and shutdown capabil-

ity. Since it is built in BCDMOS, it operates with dramatically less supply

current than it’s bipolar counterparts. The UCC3895 can operate with a

maximum clock frequency of 1MHz.

The UCC3895 and UCC2895 are offered in the 20 pin SOIC (DW) pack-

age, 20 pin PDIP (N) package, 20 pin TSSOP (PW) package, and 20 pin

PLCC (Q). The UCC1895 is offered in the 20 pin CDIP (J) package, and 20

pin CLCC package (L).

BiCMOS Advanced Phase Shift PWM Controller

FEATURES

• Programmable Output Turn-on Delay

• Adaptive Delay Set

• Bidirectional Oscillator Synchronization

• Capability for Voltage Mode or Current

Mode Control

• Programmable Soft Start/Soft Stop

and Chip Disable via a Single Pin

• 0% to 100% Duty Cycle Control

• 7MHz Error Amplifier

• Operation to 1MHz

• Low Active Current Consumption

(5mA Typical @ 500kHz)

• Very Low Current Consumption

During Undervoltage Lock-out

(150

mA typical)

SLUS157B - DECEMBER 1999 - REVISED JANUARY 2001

1

10

11

12

13

14

15

16

17

18

19

7

7

7

7

7

7

7

7

7

20

2

3

4

5

6

7

8

9

UCC3895

EAN

EAP

EAOUT

RAMP

REF

GND

SYNC

CT

RT

DELAB

DELCD

ADS

CS

OUTD

OUTC

VCC

PGND

OUTB

OUTA

SS/DISB

Q1

D

B

AC

V

IN

V

OUT

V

BIAS

SIMPLIFIED APPLICATION DIAGRAM

UDG-98139

application

INFO

available