BiCMOS Advanced Phase Shift PWM Controller - Unitrode
Description
application INFO available
BiCMOS Advanced Phase Shift PWM Controller
UCC1895 UCC2895 UCC3895
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 (150µA typical)
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 modulation in conjunction with resonant zero-voltage switching to provide high efficiency 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 capability.
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) package, 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).
SIMPLIFIED APPLICATION DIAGRAM
1 EAN
UCC3895
EAP 270
2 EAOUT
SS/DISB 19
3 RAMP
OUTA 18
4 REF
OUTB 17
5 GND
PGND 16
6 SYNC
VCC 15
7 CT
OUTC 14
8 RT
OUTD 13
9 DELAB
CS 12
10 DELCD
ADS 11
Q1 VBIAS
A B
VOUT
C VIN
D
SLUS157A - DECEMBER 1999
UDG-98139
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (IDD < 10mA) .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
17V Supply Current .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
Similar Datasheet