UCC2819A UCC3819A
ą
SLUS579 − OCTOBER, 2003
PROGRAMMABLE OUTPUT POWER FACTOR PREREGULATOR
FEATURES D Controls Boost Pre...
UCC2819A UCC3819A
ą
SLUS579 − OCTOBER, 2003
PROGRAMMABLE OUTPUT POWER FACTOR PREREGULATOR
FEATURES D Controls Boost Preregulator to Near-Unity
Power Factor
D World Wide Line Operation D Over-
Voltage Protection D Accurate Power Limiting D Average Current Mode Control D Improved Noise Immunity D Improved Feed-Forward Line Regulation D Leading Edge Modulation D 150-µA Typical Start-Up Current D Low-Power Bi
CMOS Operation D 10.8-V to 17-V Operation D Programmable Output
Voltage (Tracking
Boost Topology)
BLOCK DIAGRAM
OVP/EN 10
DESCRIPTION
The UCC2819A/UCC3819A provides all the functions necessary for active power factor corrected preregulators. The controller achieves near unity power factor by shaping the ac-input line current waveform to correspond to that of the ac-input line
voltage. Average current mode control maintains stable, low distortion sinusoidal line current.
Designed in Texas Instrument’s Bi
CMOS process, the UCC3819A offers new features such as lower start-up current, lower power dissipation, over
voltage protection, a shunt UVLO detect circuitry and a leading-edge modulation technique to reduce ripple current in the bulk capacitor.
The UCC3819A allows the output
voltage to be programmed by bringing out the error amplifier noninverting input.
VCC 15
7.5 V REFERENCE
9 VREF
VAOUT 7 VSENSE 11
VAI 13 VFF 8
IAC 6 MOUT 5
VOLTAGE − ERROR AMP +
X2
÷X MULT X
MIRROR 2:1
1.9 V
− +
0.33 V
CURRENT AMP
−
+
ENABLE
ZERO POWER −
+ 8.0 V + OVP
−
− PWM + OSC
CLK
SQ
...