AN3399
L99PM62GXP external voltage regulation
with bipolar transistor
Introduction
The following application note describes the L99PM62GXP external schematic and relevant
characteristics for operating an external voltage regulation for driving a load up to 200 mA.
The first paragraph contains the detailed schematic description. The second paragraph
contains exhaustive static so that dynamic evaluations and demonstrates the regulation
stability in case of V
S
and/or current load variations.
September 2013
Doc ID 018824 Rev 2
1/24
www.st.com
Contents
AN3399
Contents
1
Voltage regulation circuit schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1
1.2
1.3
1.4
Regulation with external PNP without current limitation . . . . . . . . . . . . . . . 5
Regulation with external NPN without current limitation . . . . . . . . . . . . . . . 6
Voltage regulation and current limitation with external PNP . . . . . . . . . . . . 7
Voltage regulation and current limitation with external NPN . . . . . . . . . . . 8
2
Evaluations of circuit with PNP and current limitation . . . . . . . . . . . . . 9
2.1
Static characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.1
2.1.2
2.1.3
Standby current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Line regulation 6-18 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Load regulation up to 250 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2
Dynamical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2.1
2.2.2
2.2.3
2.2.4
V
3
switching ON / OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Load switch ON/OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Influence of C
i
and C
1
on the V
3
switch and load variation response . . 14
V
S
cranking measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Appendix A Reference document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2/24
Doc ID 018824 Rev 2
AN3399
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
V
3
to V
S
dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
V
3
to I
3
dependence for V
S
= 6, 12, 18 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Capacitors combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Doc ID 018824 Rev 2
3/24
List of figures
AN3399
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Voltage regulation with external PNP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Voltage regulation with external NPN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Voltage regulation and current limitation with external PNP . . . . . . . . . . . . . . . . . . . . . . . . . 7
Voltage regulation and current limitation with external NPN. . . . . . . . . . . . . . . . . . . . . . . . . 8
Removing residual current by turning L99PM62GXP in standby mode . . . . . . . . . . . . . . . . 9
V
3
to V
S
dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
V
3
to I
3
dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Screenshot of load regulation (from 0 to 220 mA - current limitation). . . . . . . . . . . . . . . . . 12
V
3
switch ON / OFF (I
3
= 0 mA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V
3
switch ON /OFF (I
3
= 200 mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
V
3
switch ON /OFF to shortcut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Load switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Combination n°1 - I
3
= 0; I
3
= 200 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Combination n°1 - C
i
= 0; C
1
= 0; load switch ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Combination n°2 - I
3
= 0; C
i
= 1 nF; C
1
= 0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Combination n°2 - I
3
= 200 mA; C
i
= 1 nF; C
1
= 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Combination n°2 - C
i
= 1 nF; C
1
= 0; load switch ON/OFF. . . . . . . . . . . . . . . . . . . . . . . . . 16
Combination n°3 - I
3
= 0; C
i
= 10 nF; C
1
= 0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Combination n°3 - I
3
= 200 mA; C
i
= 10 nF; C
1
= 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Combination n°3 - C
i
= 10 nF; C
1
= 0; load switch ON/OFF. . . . . . . . . . . . . . . . . . . . . . . . 17
Combination n°5 - I
3
= 0; C
i
= 1 nF; C
1
= 10 µF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Combination n°5 - I
3
= 200 mA; C
i
= 1 nF; C
1
= 10 µF . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Combination n°5 - C
i
= 1 nF; C
1
= 10 µF; load switch ON/OFF . . . . . . . . . . . . . . . . . . . . . 18
Combination n°6 - I
3
= 0; C
i
= 10 nF; C
1
= 10 µF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Combination n°6 - I
3
= 200 mA; C
i
= 10 nF; C
1
= 10 µF . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Combination n°6 - C
i
= 10 nF; C
1
= 10 µF; load switch ON/OFF . . . . . . . . . . . . . . . . . . . . 19
V
S
cranking (1 ms pulse) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
V
S
cranking (pulse 2 ms) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
V
S
cranking (pulse 5 ms) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4/24
Doc ID 018824 Rev 2
AN3399
Voltage regulation circuit schematics
1
1.1
Voltage regulation circuit schematics
Regulation with external PNP without current limitation
Figure 1.
Voltage regulation with external PNP
The
Figure 1
is an example of recommended circuit for voltage regulation with external
transistor. As a reference voltage source was used 5V1 voltage regulator of L99PM62GXP.
Parameters of circuit at
Figure 1
are:
●
●
●
Output voltage = 5.0 V
Output current from 0 to approx. 1 A (no limitation), for V
S
+-12 V
V
S
operation range from 5.5 to 18 V; for output current up to 200 mA the theoretical
minimum operational range is from 5.2 V. (V
S
is the voltage after reverse polarity
protection).
The output voltage is possible set by change of R1 and R2 value. In case of R3 = R4 the U3
is possible express from equation:
R
1
+
R
2
R
4
U
3
=
U
5V1
-------------------- + --------------------
V
-
-
R
+
R
R
3
4
2
Important requirement is to ensure the voltage on OP_- and OP_+ inputs is bellow 3 V.
Doc ID 018824 Rev 2
5/24
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