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SLUS794 – NOVEMBER 2007
Two-Phase Interleaved CCM PFC Controller
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FEATURES
Interleaved Average Current-Mode PWM
Control with Inherent Current Matching
Advanced Current Synthesizer Current
Sensing for Superior Efficiency and PF
Highly-Linear Multiplier Output with Internal
Quantized Voltage Feed-Forward Correction
for Near-Unity PF
Programmable Frequency (up to 300 kHz)
Programmable Maximum Duty-Cycle Clamp
Programmable Frequency Dithering Rate and
Magnitude for Enhanced EMI Reduction
– Magnitude: Up to 30 kHz
– Rate: Up to 30 kHz
External Clock Synchronization Capability
Enhanced Load and Line Transient Response
through Voltage Amplifier Output Slew-Rate
Correction
Programmable Peak Current Limiting
Bias-Supply UVLO, Over-Voltage Protection,
Open-Loop Detection, and PFC-Enable
Monitoring
External PFC-Disable Interface
Open-Circuit Protection on VSENSE and
VINAC pins
Programmable Soft Start
20-Lead TSSOP Package
APPLICATIONS
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High-Efficiency Server and Desktop Power
Supplies
Telecom Rectifiers
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DESCRIPTION
The UCC28070 is an advanced power factor
correction device that integrates two pulse-width
modulators (PWMs) operating 180° out of phase.
This Natural Interleaved PWM operation generates
substantial reduction in the input and output ripple
currents, and the conducted-EMI filtering becomes
easier and less expensive. A significantly improved
multiplier design provides a shared current reference
to two independent current amplifiers that ensures
matched average current mode control in both PWM
outputs while maintaining a stable, low-distortion
sinusoidal input line current.
The UCC28070 contains multiple innovations
including current synthesis and quantized voltage
feed-forward to promote performance enhancements
in PF, efficiency, THD, and transient response.
Features including frequency dithering, clock
synchronization, and slew rate enhancement further
expand the potential performance enhancements.
The UCC28070 also contains a variety of protection
features including output over-voltage detection,
programmable peak-current limit, in-rush current
detection, under-voltage lockout, and open-loop
protection.
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Typical Application Diagram
V
IN
L1
D1
V
OUT
+
C
OUT
–
12V to 21V
To CSB
C
CDR
R
RDM
R
A
1 CDR
2 RDM
3 VAO
4 VSENSE
5 VINAC
DMAX 20
RT 19
SS 18
GDB 17
GND 16
VCC 15
GDA 14
R
DMX
R
RT
C
SS
R
S
T1
M1
R
IMO
R
B
R
SYN
6 IMO
7 RSYNTH
8 CSB
9 CSA
10 PKLMT
L2
VREF 13
CAOA 12
To CSA
D2
CAOB 11
R
S
T2
R
A
From Ixfrms
C
ZV
C
PV
R
PK2
R
ZV
R
ZC
R
ZC
R
PK1
C
ZC
C
REF
C
PC
C
PC
C
ZC
M2
R
B
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCT PREVIEW information concerns products in the
formative or design phase of development. Characteristic data and
other specifications are design goals. Texas Instruments reserves
the right to change or discontinue these products without notice.
Copyright © 2007, Texas Instruments Incorporated
PRODUCT PREVIEW
TI [ TEXAS INSTRUMENTS ]
