®
TSM101/A
VOLTAGE AND CURRENT CONTROLLER
.
.
.
.
.
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
N
DIP8
(Plastic Package)
D
SO8
(Plastic Micropackage)
P
TSSOP8
(Thin Shrink Small Outline Package)
ORDER CODES
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...
June 1999
Part Number
TSM101C/AC
TSM101I/AI
Temperature
Range
-20, +80
o
C
-40, +105 C
o
Package
N
•
•
D
•
•
P
•
•
PIN CONNECTIONS
1
2
3
4
Vref
8
7
6
5
1/15
TSM101/A
ABSOLUTE MAXIMUM RATINGS
Symbol
V
CC
I
out
P
d
V
in
I
in
T
stg
T
j
T
thja
Output Current - (note 2)
Power Dissipation
Input Voltage - (note 3)
Input Current
Storage Temperature
Maximum Junction Temperature
Thermal Resistante Junction to Ambiant
Parameter
DC Supply Voltage - (note 1)
Value
36
20
200
-0.3, V
CC
-1.5
±1
-40 to +125
150
130 to 200
o
Unit
V
mA
mW
V
mA
o
o
C
C
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
OPERATING CONDITIONS
Symbol
V
CC
T
oper
Supply Voltage
Operating Free Air Temperature Range
Parameter
TSM101C/AC/I/AI
Value
4.5 to 32
T
min.
to T
max.
Unit
V
o
C
ELECTRICAL CHARACTERISTICS
T
amb
= 25
o
C, V
CC
= 15V (unless otherwise specified)
OPERATIONAL AMPLIFIER :
TSM101C/I/AC/AI
Symbol
I
CC
V
i
V
io
I
ib
Parameter
Total Supply Current
Input Voltage Range
Input Offset Voltage
Input Bias Current
@ V
in
= 1.2V on pin 7 and V
in
= 0V on pin 5
Output Sink Current, V
ol
= 2.5V
Large Signal Voltage Gain
Supply Voltage Rejection Ratio
Common Mode Rejection Ratio
Gain Bandwidth Product
25 C
T
min.
<T
amb.
<T
max.
25 C
T
min.
<T
amb.
<T
max.
25 C
T
min.
<T
amb.
<T
max.
R
L
= 2kΩ
T
min.
<T
amb.
<T
max.
T
min.
<T
amb.
<T
max.
T
min.
<T
amb.
<T
max.
V
CC
= 15V, F = 100kHz
V
in
= 10mV, RL = 2kΩ
C
L
= 100pF
25 C
T
min.
<T
amb.
<T
max.
o
o
o
o
Test Conditions
V
CC
= 15V
Min.
0
-5
-7
-700
-1000
8
Typ.
Max.
2
V
CC
-1.5V
Unit
mA
V
mV
nA
1
5
7
0
0
-300
15
I
sink
A
vo
SVR
CMR
GBP
mA
V/mV
15
65
90
80
1
dB
dB
MHz
µA
I
oh
Output Leakage Current
2
7
2/15
TSM101/A
8
Vre f
Gnd
Vrin
Cse n
Crre f
Crin
2
3
5
6
OUTP UT
1
4
7
Vre f
+Vcc
DESCRIPTION
Name
V
ref
V
rin
C
rin
C
rref
C
sen
Pin
1
7
5
3
2
Type
OUTPUT
INPUT
INPUT
INPUT
INPUT
Voltage Regulation Loop Input
Current Limitation Loop Input, connected to the sense resistor
Current Limitation Reference 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 pin common to the voltage regulation and current limitation
loops. This output can drive the primary side (LED) of an optocoupler.
Power Supply Input (4.5 to 32VDC)
Ground
Function
Voltage Reference Output 1.24V, 10mA max. Do not short circuit
OUTPUT
V
CC
GND
6
8
4
OUTPUT
INPUT
INPUT
4/15
TSM101/A
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)
Figure 1 :
TSM101 Schematic Diagram
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.
1
2
3
4
Vref
8
7
6
5
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.
5/15
Talking
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