參數(shù)資料
型號(hào)： HA17431UPA
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： HA17431UPA
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
HA17431VUP Infrared Temperature Sensor; Sensor Output Type:K thermocouple; Field of View:10:1; Sensor Terminals:Cable; Accuracy: 1%; Features:Miniature Sensing Head with separate electronics; Response Time:200ms; Supply Voltage:24VDC
HA17431H Shunt Regulator
HA17431HLP Shunt Regulator
HA17431HLTP Shunt Regulator
HA17431HP Shunt Regulator
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HA17431VLP 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.
HA17431VLP-E 制造商:Renesas Electronics Corporation 功能描述:IC, HA17431VLP-E
HA17431VLPEL-E 制造商:Renesas Electronics 功能描述:Bulk 制造商:Renesas Electronics Corporation 功能描述:Shunt Regulator,2.500V 1%,50mA,MPAK-5V
HA17431VLTP 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.
HA17431VLTP-E 制造商:Renesas Electronics Corporation 功能描述:Power Sup,Shunt Req.,Vka=16V,Vref=2.500V
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