The UCC28070A is an extended frequency range derivative of UCC28070, capable of operating at low switching frequencies desired for IGBT power switch based PFC converters in high power applications

UCC28070A

Manufacturer Part NumberUCC28070A
DescriptionThe UCC28070A is an extended frequency range derivative of UCC28070, capable of operating at low switching frequencies desired for IGBT power switch based PFC converters in high power applications
ManufacturerTexas Instruments
UCC28070A datasheet
 


Specifications of UCC28070A

Uvlo Thresholds On/off(v)10.2/9.2Operating Supply(max)(v)21
Startup Current(ma)20Operating Supply Current(ma)20
Vref(v)6Vref Tol(%)3
Duty Cycle(max)(%)99Practical Operating Frequency(max)(mhz)0.3
Pin/package20TSSOP  
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Extended Frequency Range (10 kHz to 300 kHz),
Interleaving Continuous Conduction Mode PFC Controller
FEATURES
1
Interleaved Average Current-Mode PWM
Control with Inherent Current Matching
Advanced Current Synthesizer Current
Sensing for Superior Efficiency
Highly-Linear Multiplier Output with Internal
Quantized Voltage Feed-Forward Correction
for Near-Unity PF
Extended Range Programmable Frequency (10
kHz to 300 kHz)
Programmable Maximum Duty-Cycle Clamp
Programmable Frequency Dithering Rate and
Magnitude for Enhanced EMI Reduction
– Magnitude: 3 kHz 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
From Ixfrms
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Check for Samples:
UCC28070A
APPLICATIONS
Air Conditioners and White Goods
PFC Applications with IGBT Power Switches
High-Efficiency Server and Desktop Power
Supplies
Telecom Rectifiers
Industrial Equipment
DESCRIPTION
The UCC28070A is an extended frequency range
derivative of UCC28070, capable of operating at low
switching frequencies desired for IGBT power switch
based PFC converters in high power applications.
The UCC28070A is capable of operating in frequency
range 10 kHz to 300 khz, thus extending the range of
operation compared to UCC28070 whose minimum
operating frequency was limited to 30 khz. All the
other features and benefits of UCC28070 are also
available in UCC28070A. The 180 degree out-of-
phase interleaved operation generates substantial
reduction in input and output ripple currents and
conducted EMI filtering becomes easier and less
expensive.
Simplified Application Diagram
V
IN
12V to 21V
To CSB
C
CDR
1
CDR
DMAX
20
R
DMX
R
RDM
2
RDM
RT
19
R
R
RT
A
3
VAO
SS
18
C
SS
4
VSENSE
GDB
17
5
VINAC
GND
16
R
IMO
6
IMO
VCC
15
R
R
B
7
RSYNTH
GDA
14
SYN
8
CSB
VREF
13
9
CSA
CAOA
12
To CSA
10
PKLMT
CAOB
11
C
C
C
R
ZV
ZC
ZC
PK1
C
REF
C
C
C
PV
PC
PC
R
PK2
R
R
R
ZV
ZC
ZC
UCC28070A
SLUSAW0 – MARCH 2012
L1
D1
V
OUT
C
OUT
R
T1
S
M1
L2
D2
R
T2
S
R
A
M2
R
B
Copyright © 2012, Texas Instruments Incorporated

UCC28070A Summary of contents

  • Page 1

    ... UCC28070, capable of operating at low switching frequencies desired for IGBT power switch based PFC converters in high power applications. The UCC28070A is capable of operating in frequency range 10 kHz to 300 khz, thus extending the range of operation compared to UCC28070 whose minimum operating frequency was limited to 30 khz. All the other features and benefits of UCC28070 are also available in UCC28070A ...

  • Page 2

    ... SLUSAW0 – MARCH 2012 DESCRIPTION (CONT.) Like UCC28070, UCC28070A also features 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 ...

  • Page 3

    ... JT , using a procedure described in JESD51-2a (sections 6 and 7 estimates the junction temperature of a device in a real system and is extracted JB , using a procedure described in JESD51-2a (sections 6 and 7). JA Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 UNIT V MIN MAX UNIT ...

  • Page 4

    ... 2.2 nF 100 kΩ CDR RDM C = 0.3 nF 100 kΩ CDR RDM Measure at CDR (sink and source) Measured at C (rising) CDR Product Folder Link(s): UCC28070A www.ti.com = 75 kΩ 68.1 RT DMX = 0 mA (unless otherwise noted) MIN TYP MAX UNITS ...

  • Page 5

    ... Measured at VAO, in addition to VAO source current. Measured at SS (rising) VSENSE = 0.5 V, VAO = 1 V VSENSE = 0 VSENSE = 2 Measured as VSENSE – SS VSENSE = 0 0.2 V Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 = 75 kΩ 68.1 RT DMX = 0 mA (unless otherwise noted) MIN TYP MAX ...

  • Page 6

    ... VINAC = 0 V, VAO = 5 V Measured at VINAC (rising) RSYNTH = 25°C A RSYNTH = 6 V Measured as Phase A’s input offset minus Phase B’s input offset VSENSE = 0.5 V, CAOx = 0.2 V Product Folder Link(s): UCC28070A www.ti.com = 75 kΩ 68.1 RT DMX = 0 mA (unless otherwise noted) MIN TYP MAX ...

  • Page 7

    ... LOAD LOAD LOAD LOAD VCC = 2.5 mA GDA GDB Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 = 75 kΩ 68.1 RT DMX = 0 mA (unless otherwise noted) MIN TYP MAX UNITS 2.91 3 3.09 0.10 0.15 0. ...

  • Page 8

    ... RDM VAO 3 SS VSENSE 4 17 GDB VINAC 5 16 GND IMO 6 15 VCC RSYNTH 7 14 GDA CSB 8 13 VREF CSA 9 12 CAOA PKLMT CAOB 10 11 TERMINAL FUNCTIONS DESCRIPTION . LB Product Folder Link(s): UCC28070A www.ti.com , VINAC, IN Copyright © 2012, Texas Instruments Incorporated ...

  • Page 9

    ... PWM maximum duty-cycle based on the ratio of R Copyright © 2012, Texas Instruments Incorporated TERMINAL FUNCTIONS (continued) DESCRIPTION until Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 exceeds 3 V. Upon recovery from certain fault /R . DMX RT Submit Documentation Feedback 9 ...

  • Page 10

    ... ReStart 10uA + PWM 1 CA1 + GmAmp OutA OffA OutB IpeakA Fault + PWM 2 CA2 VINAC + GmAmp VSENSE OffB IpeakB Fault Product Folder Link(s): UCC28070A www.ti.com + VSENSE OVP 3.18V 3.08V 0.75V + Ext.Disable 0.60V SS 0.90V + ZeroPwr 0.75V VAO VINAC 250nA 3 VAO + ...

  • Page 11

    ... C 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0. 100 120 140 - Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 REFERENCE VOLTAGE vs TEMPERATURE VREF ( mA) VREF - 140 Temperature - C J Figure 2. I BIAS CURRENT VSENSE vs TEMPERATURE - 140 Temperature - ...

  • Page 12

    ... VINAC = 2.85 V 0.0 −0.2 −0.4 −0.6 −0.8 −1.0 VINAC = 2.0 V −60 −40 −20 90 140 0 C Product Folder Link(s): UCC28070A www.ti.com MULTIPIER CONSTANT vs TEMPERATURE VAO = 3.0 V VAO = 5.0 V VAO = 1.5 V VAO = 1 100 120 Temperature - C J Figure 6. SWITCHING FREQUENCY vs TEMPERATURE Typ 290 kHz ...

  • Page 13

    ... C CURRENT AMPLIFIER TRANSCONDUCTANCE vs TEMPERATURE -60 -40 - Temperature - C J Figure 11. Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 vs VSENSE 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 VSENSE - V Figure 10. 100 120 140 Submit Documentation Feedback 3.5 13 ...

  • Page 14

    ... C TEMPERATURE (at 2.0 V common mode -10 - 100 120 140 -60 - Product Folder Link(s): UCC28070A www.ti.com CA1 TO CA2 RELATIVE OFFSET vs A-B +3s A-B AVG A-B -3s - 100 120 Temperature - C J Figure 13. CA1 TO CA2 RELATIVE OFFSET vs ...

  • Page 15

    ... Copyright © 2012, Texas Instruments Incorporated TEMPERATURE (at 3.6 V common mode -10 - 100 120 140 -60 - Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 CA1 TO CA2 RELATIVE OFFSET vs A-B +3s A-B AVG A-B -3s - 100 120 Temperature - C J Figure 17 ...

  • Page 16

    ... OUT ö ÷ 1 ÷ ø ö ÷ 1 ÷ ø = average PFC output voltage Product Folder Link(s): UCC28070A www.ti.com sizes. Additionally, reduced high PWM = peak of the M . The rms currents Crms1φ Copyright © 2012, Texas Instruments Incorporated (1) (2) ...

  • Page 17

    ... Programming the PWM Frequency and Maximum Duty-Cycle Clamp The PWM frequency and maximum duty-cycle clamps for both GDx outputs of the UCC28070A are set through the selection of the resistors connected to the RT and DMAX pins, respectively. The selection of the RT resistor (R ) directly sets the PWM frequency (f ...

  • Page 18

    ... SLUSAW0 – MARCH 2012 External Clock Synchronization The UCC28070A has also been designed to be easily synchronized to almost any external frequency source. By disabling frequency dithering (pulling CDR > 5 V), the UCC28070A’s SYNC circuitry is enabled permitting the internal oscillator to be synchronized with pulses presented on the RDM pin. In order to ensure a precise 180 ...

  • Page 19

    ... VSENSE and VINAC Open Circuit Protection Both the VSENSE and VINAC pins have been designed with an internal 250-nA current sink to ensure that in the event of an open circuit at either pin, the voltage is not left undefined, and the UCC28070A remains in a “safe” operating mode. ...

  • Page 20

    ... R B CSB1 From Ixfrms CSA1 Vin CSB2 From Ixfrms CSA2 Synchronized Clocks o w/ 180 Phase Shift Figure 18. Simplified Four-Phase Application Diagram Using Two UCC28070A 20 Submit Documentation Feedback R 1 DMX 1 CDR DMAX 20 2 RDM VAO SS 18 ...

  • Page 21

    ... Meanwhile, the continuous monitoring of the input and output voltage via the VINAC and VSENSE pins permits the UCC28070A to internally recreate the inductor current’s down-slope during each output’s respective off-time. Through the selection of the RSYNTH ...

  • Page 22

    ... SLUSAW0 – MARCH 2012 Programmable Peak Current Limit The UCC28070A has been designed with a programmable cycle-by-cycle peak current limit dedicated to disabling either GDA or GDB output whenever the corresponding current-sense input (CSA or CSB respectively) rises above the voltage established on the PKLMT pin. Once an output has been disabled via the detection of peak current limit, the output remains disabled until the next clock cycle initiates a new PWM period ...

  • Page 23

    ... Linear Multiplier The multiplier of the UCC28070A generates a reference current which represents the desired wave shape and proportional amplitude of the ac input current. This current is converted to a reference voltage signal by the R resistor, which is scaled in value to match the voltage of the current-sense signals. The instantaneous multiplier ...

  • Page 24

    ... P = 0.76 V, hence Q = 0.398 and input V VFF I 1 414 . I = ´ rms ) Product Folder Link(s): UCC28070A www.ti.com (13) will adjust slightly upwards or VAO voltage range to compensate for VFF varies, both within a level IN input, the discrete RMS varies within RMS ...

  • Page 25

    ... PKLMT threshold, the full variation of maximum input power will be seen, but the input currents will inherently be below the maximum acceptable current levels of the power stage. The performance of the multiplier in the UCC28070A has been significantly enhanced when compared to previous generation PFC controllers, with high linearity and accuracy over most of the input ranges. The ...

  • Page 26

    ... Load transients on the other hand can only be handled by the voltage loop, therefore, VFF the UCC28070A has been designed to improve its transient response by pulling up on the output of the voltage amplifier (VAO) with an additional 100 μA of current in the event the VSENSE voltage drops below 93% of regulation (2.79 V). During a soft-start cycle, when VSENSE is ramping up from the 0.75-V PFC Enable threshold, the 100-μ ...

  • Page 27

    ... Adaptive Soft Start In order to maintain a controlled power up, the UCC28070A has been designed with an adaptive soft-start function that overrides the internal reference voltage with a controlled voltage ramp during power up. On initial power up, once V exceeds the 0.75-V enable threshold (V VSENSE released, and the 1.5-mA adaptive soft-start current source is activated. This 1.5-mA pull-up almost immediately pulls the SS pin to 0 ...

  • Page 28

    ... SLUSAW0 – MARCH 2012 PFC Start-Up Hold Off An additional feature designed into the UCC28070A is the “Start-Up Hold Off” logic that prevents the device from initiating a soft-start cycle until the VAO is below the zero-power threshold (0.75 V). This feature ensures that the SS cycle will initiate from zero-power and zero duty-cycle while preventing the potential for any significant inrush currents due to stored charge in the VAO compensation network ...

  • Page 29

    ... Current Loop Compensation The UCC28070A incorporates two identical and independent transconductance-type current-error amplifiers (one for each phase) with which to control the shaping of the PFC input current waveform. The current-error amplifier (CA) forms the heart of the embedded current control loop of the boost PFC pre-regulator, and is compensated for loop stability using familiar principles [4, 5] ...

  • Page 30

    ... C ZC CXO further attenuate ripple and noise at f PWM , across the R pc NOTE should be determined at maximum inductance. ZC Product Folder Link(s): UCC28070A www.ti.com amplitude RMP is the transconductance of mc CXO . phase margin ZC ZC CXO < ...

  • Page 31

    ... For every 1% of 3rd- harmonic input distortion allowable, the small-signal gain G frequency should allow no more than 2% ripple over the full VAO voltage range. In the UCC28070A, V range from zero load power to ~4.2 V(see note below) at full load power for a Δ 64-mV peak ripple ...

  • Page 32

    ... C , and solve for and C may be manipulated to observe their effects NOTE voltage ripple on C only. Other sources of distortion, such as OUT Product Folder Link(s): UCC28070A www.ti.com is the average OUT(avg therefore, 2LF OV 2LF ) ´ /10 allows one to ...

  • Page 33

    ... These two current signals are summed together to form the entire inductor current, but this is not the case for the UCC28070A. A major advantage of the UCC28070A design is the current synthesis function, which internally recreates the inductor current down-slope during the switching period off-time. This eliminates the need for the diode-leg CT in each phase, significantly reducing space, cost and complexity ...

  • Page 34

    ... The design condition should be at the lowest maximum input power CMCAO CSx , and R SER LK to quickly rise to its maximum, programming a maximum duty-cycle at CAOx Product Folder Link(s): UCC28070A www.ti.com is too low, there may be high CT and one-turn primary LK d CSx D ...

  • Page 35

    ... In order to accommodate various CT circuit designs and prevent the potentially destructive result due to CT saturation, the UCC28070A’s maximum duty-cycle needs to be programmed such that the resulting minimum off- time accomplishes the required worst-case reset. (See the PWM Frequency and Duty-Cycle Clamp section of the ...

  • Page 36

    ... Current Sense Offset and PWM Ramp for Improved Noise Immunity To improve noise immunity at extremely light loads, a PWM ramp with a dc offset is recommended to be added to the current sense signals. Electrical components R C form a PWM ramp that is activated and deactivated by the gate drive outputs of the UCC28070A. Resistor TB R and R ...

  • Page 37

    ... Figure 27. False Current Sense Signal and and OFF OFF Product Folder Link(s): UCC28070A UCC28070A SLUSAW0 – MARCH 2012 to ensure that when the unit goes OB (35) (36) ) less the offset can then be S (37) (38) Submit Documentation Feedback 37 ...

  • Page 38

    ... Design Seminar Manual SEM700, 1990. Texas Instruments Literature Number SLUP093 Dixon, "High Power Factor Preregulator for Off-Line Power Supplies", Unitrode Power Supply Design Seminar Manual SEM600, 1988. Texas Instruments Literature Number SLUP087 38 Submit Documentation Feedback Product Folder Link(s): UCC28070A www.ti.com Copyright © 2012, Texas Instruments Incorporated ...

  • Page 39

    ... Orderable Device (1) Package Type Package Status UCC28070APW PREVIEW TSSOP UCC28070APWR PREVIEW TSSOP (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. ...

  • Page 40

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  • Page 41

    ... Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’ ...