TSM101/A
VOLTAGE AND CURRENT CONTROLLER
June 1999
1
2
3
4
8
5
6
7
Vref
PIN CONNECTIONS
.
1.24V SERIES VOLTAGE REFERENCE WITH
10mA OUTPUT CURRENT AND 1% PRECI-
SION (TSM101A)
.
TWO
OPERATIONAL AMPLIFIERS WITH
ORED OUTPUT AND 1MHZ GAIN BAND-
WIDTH PRODUCT
.
BUILT-IN CURRENT GENERATOR WITH EN-
ABLE/DISABLE FUNCTION
.
4.5 TO 32V SUPPLY VOLTAGE RANGE
.
SO8, DIP8 AND TSSOP8 PACKAGES
DESCRIPTION
The TSM101/TSM101Aintegrated circuit incorpo-
rates a high stability series band gap voltage refer-
ence, two ORed operational amplifiers and a
current source.
This IC compares the DC voltage and the current
level at the output of a switching power supply to
an internal reference. It provides a feedback
through an optocoupler to the PWM controller IC in
the primary side.
The controlled current generator can be used to
modify the level of current limitation by offsetting
the information coming from the current sensing
resistor.
APPLICATIONS
This circuit is designed to be used in battery charg-
ers with a constant voltage and a limited output
current.
It can be used in every types of applicationrequiring
a precision voltage regulation and current limita-
tion.
Other applications include voltage supervisors,
over voltage protection...
ORDER CODES
Part Number
Temperature
Range
Package
N
D
P
TSM101C/AC
-20, +80
o
C
TSM101I/AI
-40, +105
o
C
N
DIP8
(Plastic Package)
D
SO8
(Plastic Micropackage)
P
TSSOP8
(Thin Shrink Small Outline Package)
1/15
OPERATING CONDITIONS
Symbol
Parameter
TSM101C/AC/I/AI
Unit
Value
V
CC
Supply Voltage
4.5 to 32
V
T
oper
Operating Free Air Temperature Range
T
min.
to T
max.
o
C
ELECTRICAL CHARACTERISTICS
T
amb
= 25
o
C, V
CC
= 15V (unless otherwise specified)
OPERATIONAL AMPLIFIER : TSM101C/I/AC/AI
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
I
CC
Total Supply Current
V
CC
= 15V
2
mA
V
i
Input Voltage Range
0
V
CC
-1.5V
V
V
io
Input Offset Voltage
25
o
C
T
min.
<T
amb.
<T
max.
-5
-7
1
5
7
mV
I
ib
Input Bias Current
@ V
in
= 1.2V on pin 7 and V
in
= 0V on pin 5
25
o
C
T
min.
<T
amb.
<T
max.
-700
-1000
-300
0
0
nA
I
sink
Output Sink Current, V
ol
= 2.5V
25
o
C
T
min.
<T
amb.
<T
max.
8
15
mA
A
vo
Large Signal Voltage Gain
R
L
= 2k
T
min.
<T
amb.
<T
max.
15
V/mV
SVR
Supply Voltage Rejection Ratio
T
min.
<T
amb.
<T
max.
65
90
dB
CMR
Common Mode Rejection Ratio
T
min.
<T
amb.
<T
max.
80
dB
GBP
Gain Bandwidth Product
V
CC
= 15V, F = 100kHz
V
in
= 10mV, RL = 2k
C
L
= 100pF
1
MHz
I
oh
Output Leakage Current
25
o
C
T
min.
<T
amb.
<T
max.
2
7
A
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
CC
DC Supply Voltage - (note 1)
36
V
I
out
Output Current - (note 2)
20
mA
P
d
Power Dissipation
200
mW
V
in
Input Voltage - (note 3)
-0.3, V
CC
-1.5
V
I
in
Input Current
1
mA
T
stg
Storage Temperature
-40 to +125
o
C
T
j
Maximum Junction Temperature
150
o
C
T
thja
Thermal Resistante Junction to Ambiant
130 to 200
o
C/W
Notes : 1. All voltages values, except differential voltage are with respect to network ground terminal
2. The voltage reference is not protected against permanent short circuit
TSM101/A
2/15
ELECTRICAL CHARACTERISTICS
T
amb
= 25
o
C, V
CC
= 15V (unless otherwise specified)
VOLTAGE REFERENCE : TSM101
Symbol
Parameter
Test Conditions
TSM101C
TSM101I
Unit
Min.
Typ.
Max.
Min.
Typ.
Max.
V
ref
Reference Voltage
I
out
= 1mA, T
amb.
= 25
o
C
1.21
1.24
1.27
1.21
1.24
1.27
V
K
vt
Temperature Stability
T
min.
<T
amb.
<T
max.
30
100
35
120
ppm/
o
C
R
eglo
Load Regulation
1 < I
out
< 10mA
5
15
5
15
mV
R
egli
Line Regulation
5 < V
in
< 32V
3.5
10
3.5
10
mV
VOLTAGE REFERENCE : TSM101A
Symbol
Parameter
Test Conditions
TSM101AC
TSM101AI
Unit
Min.
Typ.
Max.
Min.
Typ.
Max.
V
ref
Reference Voltage
I
out
= 1mA, T
amb.
= 25
o
C
1.227
1.24
1.252
1.227
1.24
1.252
V
K
vt
Temperature Stability
T
min.
<T
amb.
<T
max.
30
100
35
120
ppm/
o
C
R
eglo
Load Regulation
1 < I
out
< 10mA
5
15
5
15
mV
R
egli
Line Regulation
5 < V
in
< 32V
3.5
10
3.5
10
mV
CURRENT GENERATOR : TSM101, TSM101A
Symbol
Parameter
Test Conditions
TSM101C/AC
TSM101I/AI
Unit
Min.
Typ.
Max.
Min.
Typ.
Max.
I
o
Current Source
1.4
1.4
mA
K
cgt
Temperature Stability
T
min.
<T
amb.
<T
max.
500
600
ppm/
o
C
C
glir
Line Regulation
4.5 < V
CC
< 32V
0.003
0.03
0.003
0.03
mA
V
csen
Voltage at the enable
pin to have
I
O
= 1.4mA
T
min.
<T
amb.
<T
max.
0.6
0.6
V
V
csdis
Voltage at the enable
pin to have
I
O
= 0mA
T
min.
<T
amb.
<T
max.
2
2
V
I
csen
Input Current on the
C
sen
pin
T
min.
<T
amb.
<T
max.
30
30
A
I
csleak
Leakage Current
V
cs
= 2V
T
min.
<T
amb.
<T
max.
0.5
2
0.5
2
A
TSM101/A
3/15
Vre f
Vre f
Gnd
Vrin
Cs e n
Crin
Crre f
+Vcc
OUTP UT
1
8
6
4
7
2
5
3
DESCRIPTION
Name
Pin
Type
Fun ction
V
ref
1
OUTPUT
Voltage Reference Output 1.24V, 10mA max. Do not short circuit
V
rin
7
INPUT
Voltage Regulation Loop Input
C
rin
5
INPUT
Current Limitation Loop Input, connected to the sense resistor
C
rref
3
INPUT
Current Limitation Reference Input
C
sen
2
INPUT
Current source enable input. This current source can be used to
offset the voltage measurement on the sense resistor and therefore to
modify the charge current. The current source is enabled when the
input voltage on pin 2 is lower than 0.8V.
OUTPUT
6
OUTPUT
Output pin common to the voltage regulation and current limitation
loops. This output can drive the primary side (LED) of an optocoupler.
V
CC
8
INPUT
Power Supply Input (4.5 to 32VDC)
GND
4
INPUT
Ground
TSM101/A
4/15
APPLICATION NOTE
A BATTERY CHARGER USING THE TSM101
by S. LAFFONT and R. LIOU
This technical note shows how to use the TSM101
integrated circuit with a switching mode power
supply (SMPS) to realize a battery charger.
An example of realization of a 12V Nickel-cadmium
battery charger is given.
1 - TSM101 PRESENTATION
The TSM101 integrated circuit incorporates a high
stability series band gap voltage reference, two
ORed operational amplifiers and a current source
(Figure 1)
1
2
3
4
8
5
6
7
Vref
Figure 1 : TSM101 Schematic Diagram
This IC compares the DC voltage and the current
level at the output of a switching power supply to
an internal reference.It provides a feedb ack
through an optocoupler to the PWM controller IC in
the primary side.
The controlled current generator can be used to
modify the level of current limitation by offsetting
the information coming from the current sensing
resistor.
A great majority of low or medium end power
supplies is voltage regulated by using shunt pro-
grammable voltage references like the TL431
(Figure 2).
The galvanic insulation of the control information is
done by using an opto-coupler in linear mode with
a variable photo current depending on the differ-
ence between the actual output voltage and the
desired one.
A current limitation is used to protect the power
supply against short circuits, but lacks precision.
This limitation is generally realized by sensing the
current of the power transistor, in the primary side
of the SMPS.
The role of the TSM101 is to make a fine regulation
of the output current of the SMPS and a precise
voltage limitation.
The primary current limitation is conserved and
acts as a security for a fail-safe operation if a
short-circuit occurs at the output of the charger.
2 - PRINCIPLE OF OPERATION
The current regulation loop and the voltage limita-
tion loop use an internal 1.24V band-gap voltage
reference. This voltage reference has a good pre-
cision (better than 1.5%) and exhibits a very stable
temperature behavior.
The current limitation is performed by sensing the
voltage across the low ohmic value resistor R5 and
comparing it to a fixed value set by the bridge
composed by R2 and R3 (Figure 3).
When the voltage on R5 is higher than the voltage
on R3 the output of the current loop operational
amplifier decreases. The optocoupler current in-
creases and tends to reduce the output voltage by
the way of the PWM controller.
The voltage regulation is done by comparing a part
of the output voltage (resistor bridge R6, R7 and
P1) to the voltage reference (1.24V).
If this part is higher than 1.24V, the output of the
voltage loop operational amplifier decreases.
TSM101/A
5/15
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