- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄381159 > UCC2857 (Texas Instruments, Inc.) Isolated Boost PFC Preregulator Controller PDF資料下載
參數(shù)資料
| 型號(hào)： | UCC2857 |
| 廠商： | Texas Instruments, Inc. |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | Isolated Boost PFC Preregulator Controller |
| 中文描述： | 隔離升壓PFC前置穩(wěn)壓器控制器 |
| 文件頁(yè)數(shù)： | 6/10頁(yè) |
| 文件大?。?/td> | 127K |
| 代理商： | UCC2857 |
6
UCC1857
UCC2857
UCC3857
4
2
1
12
VIN
IAC
UVLO
13.75V / 10V
CRMS
RMS DETECT
AND
CONDITIONING
X
÷
X
MULT
10
VA–
3.0V
0.5V
ZERO POWER
9
SS
10
μ
A
11
VAO
7
CA–
ENBL
1.0V
ALWAYS
ON
SD
7.5V
REF
VREF
5
REF GOOD
3
ENBL
VOLTAGE AMP
13
PKLMT
CURRENT AMP
PEAK LIMIT
COMP
8
MOUT
CAO
20
CT
19
RT
OSCILLATOR
TOGGLE
F/F
Q
Q
PWM
LATCH
Q
R
R
S
R
PWM
COMP
SD
SD
TRAILING
EDGE
DELAY
DELAY
15
VD
14
MOSDRV
16
IGDRV1
18
IGDRV2
17 PGND
6
AGND
DRIVER
DRIVER
DRIVER
VD
VD
APPLICATION INFORMATION (continued)
BLOCK DIAGRAM
through the transformer and the output rectifier. It can
be seen that the
÷
operation on the primary side of the
circuit is that of a boost converter and UCC3857 pro-
vides input current programming using average current
mode control to achieve unity power factor. The trans-
former turns ratio can be used to get the required level
of output voltage (higher or lower than the peak line volt-
age). The transformer also provides galvanic isolation
for the output voltage.
Power stage optimization involves design and selection
of components to meet the performance and cost objec-
tives.
These include the power switches, transformer
and inductor design.
The choice of IGBTs is based on their advantage over
MOSFETs at higher voltages. For universal line opera-
tion, the voltage stress on the push-pull switches can
approach 1000V. However, the slow turn-off of IGBTs
can contribute high switching losses and the use of
MOSFET (QA) helps turn the IGBTs off with zero voltage
across them (ZCS turn-off). This is accomplished by
keeping QA on (beyond the turn-off of Q1 or Q2 – see
Fig. 1 for waveforms) to allow the inductor current to di-
vert from IGBT to MOSFET while the IGBT is turning off
and still maintain zero volts. The MOSFET delay time
(TD1) effectively adds to the boost inductor charge pe-
riod. The voltage stress of the MOSFET is half the stress
of the IGBTs under normal operating conditions. How-
ever, QA can see much higher voltage stress under
start-up and short circuit conditions as the converter oper-
ates in a flyback mode then. For different operating re-
quirements or constraints (e.g. single North American line
operation), the choice of switching components may be
different (e.g. MOSFETs for Q1 and Q2 and no QA) as
the voltage stress is different. In that case, UCC3857 can
still be used without using the MOSDRV output.
Transformer design is very critical in this topology. The
push-pull transformer must have minimal leakage induc-
tance between the primary and secondary windings. Simi-
larly, the leakage between the two primary windings must
be minimized. In practice, it is hard to achieve both tar-
gets without using sophisticated construction techniques
such as interleaving, use of foils etc. In many cases, it
may be beneficial to use a planar transformer to achieve
these objectives. The effects of higher leakage induc-
tance include higher voltage stresses, ringing, power
losses and loss of available duty cycle. The high voltage
levels make it difficult to design effective snubber circuits
for this leakage induced ringing.
UDG-98218
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UCC2946DTR | Industrial Control IC |
| UCC2946PWTR | 5.0 AMP POSITIVE VOLTAGE REGULATOR |
| UCC2960D | 5.0 AMP POSITIVE VOLTAGE REGULATOR |
| UCC2960DR | 5.0 AMP POSITIVE VOLTAGE REGULATOR |
| UCC2960P | Analog IC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UCC2858 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:High Efficiency, High Power Factor Preregulator |
| UCC2858 WAF | 制造商:Texas Instruments 功能描述: |
| UCC2858DW | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Power Factor Controller |
| UCC2858DWTR | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Power Factor Controller |
| UCC2858J | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。