參數(shù)資料
型號(hào)： HA17431P
廠商： Hitachi,Ltd.
英文描述： Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.
中文描述： 關(guān)于在諸如日立電器和日立二十，文件提及的瑞薩科技公司名稱變更
文件頁(yè)數(shù)： 19/26頁(yè)
文件大?。?/td> 236K
代理商： HA17431P
HA17431 Series
Rev.1, Sep. 2002, page 17 of 24
Design Guide for AC-DC SMPS
(Switching Mode Power Supply)
Use of Shunt Regulator in Transformer Secondary Side Control
This example is applicable to both forward transformers and flyback transformers. A shunt regulator is
used on the secondary side as an error amplifier, and feedback to the primary side is provided via a
photocoupler.
R
1
R
2
R
3
R
4
Transformer
Photocoupler
Light
emitting diode
Phototransistor
Output
C
1
R
5
REF
GND
A
K
V
K
I
B
I
F
HA17431
V
F
SBD
PWM IC
HA17384
HA17385
Vref
V
0
(+)
(
–
)
Figure 2 Typical Shunt Regulator/Error Amplifier
Determination of External Constants for the Shunt Regulator
DC characteristic determination:
In figure 2, R
1
and R
2
are protection resistor for the light emitting diode
in the photocoupler, and R
2
is a bypass resistor to feed I
K
minimum, and these are determined as shown
below. The photocoupler specification should be obtained separately from the manufacturer. Using the
parameters in figure 2, the following formulas are obtained:
R
1
=V
0
–
V
F
–
V
K
I
F
+ I
B
, R
2
=V
F
I
B
V
K
is the HA17431 operating voltage, and is set at around 3 V, taking into account a margin for fluctuation.
R
2
is the current shunt resistance for the light emitting diode, in which a bias current I
B
of around 1/5 I
F
flows.
Next, the output voltage can be determined by R3 and R4, and the following formula is obtained:
V
0
=R
3
+ R
4
R
4
×
Vref, Vref = 2.5 V Typ
The absolute values of R
3
and R
4
are determined by the HA17431 reference input current Iref and the AC
characteristics described in the next section. The Iref value is around 3.8
μ
A Typ. (V version: 2
μ
A Typ)
相關(guān)PDF資料
PDF描述
HA17431PA 250000 SYSTEM GATE 1.5 VOLT FPGA
HA17431VLP 250000 SYSTEM GATE 1.5 VOLT FPGA
HA17431VP Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.
HA17431UA Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.
HA17431UPA Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HA17431PA 制造商:Panasonic Industrial Company 功能描述:IC
HA17431PA-E 制造商:Renesas Electronics 功能描述:Precision Bulk 制造商:Renesas 功能描述:V-Ref Adjustable 150mA 3-Pin TO-92 Mod
HA17431PAJ 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
HA17431PA-TZ-E 制造商:Renesas Electronics Corporation 功能描述:Power Sup,Shunt Req.,Vka=40V,Vref=2.495V
HA17431P-E 制造商:Renesas Electronics 功能描述:Adjustable Bulk
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