HA17431HLP HITACHI [Hitachi Semiconductor], HA17431HLP Datasheet - Page 8

• Manufacturer Part Number: HA17431HLP
• Description: Shunt Regulator
• Manufacturer: HITACHI [Hitachi Semiconductor]

HA17431H Series
Application Hints (cont.)
No.
6
7
8
Rev.0, Sep. 2001, page 8 of 15
Application Example
Constant voltage regulator circuit
Discharge type constant current circuit
Induction type constant current circuit
V
GND
V
GND
GND
V
CC
CC
CC
R
1
Cf
R
R
2.5 V
2.5 V
R
R
Q
+
–
2
3
R
R
+
–
Q
Q
S
S
Vout
GND
I
I
L
L
Description
This is a 3-pin regulator with a discrete configuration, in
which the output voltage
R
cathode current and the output transistor Q base
current.
This circuit supplies a constant current of
I
since the HA17431H cathode current is also
superimposed on I
The requirement in this circuit is that the cathode
current must be greater than Imin = 0.2 mA. The I
setting therefore must be on the order of several mA or
more.
In this circuit, the load is connected on the collector
side of transistor Q in circuit 7 above. In this case, the
load floats from GND, but the HA17431H cathode
current is not superimposed on I
small (0.2 mA or less is possible). The constant current
value is the same as for circuit 7 above:
Vout = 2.5 V ×
I
L
L
1
≅
≅
is a bias resistance for supplying the HA17431H
2.5 V
2.5 V
R
R
S
S
[A] into the load. Caution is required
[A]
(R
2
R
L
+ R
.
3
3
)
L
, so that I
L
can be kept
L