TSM101/A
VOLTAGE AND CURRENT CONTROLLER
s
1.24V SERIES VOLTAGE REFERENCE
s
s
s
s
WITH 10mA OUTPUT CURRENT AND 1%
PRECISION (TSM101A)
TWO OPERATIONAL AMPLIFIERS WITH
ORED OUTPUT AND 1MHZ GAIN BAND-
WIDTH PRODUCT
BUILT-IN CURRENT GENERATOR WITH
ENABLE/DISABLE FUNCTION
4.5 TO 32V SUPPLY VOLTAGE RANGE
SO8 AND DIP8 PACKAGES
DESCRIPTION
The TSM101/TSM101A integrated circuit incorpo-
rates a high stability series band gap voltage refer-
ence, two ORed operational amplifiers and a cur-
rent 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
chargers with a constant voltage and a limited out-
put current.
It can be used in every types of application requir-
ing a precision voltage regulation and current limi-
tation.
Other applications include voltage supervisors,
over voltage protection...
ORDER CODE
Part Number
TSM101C/AC
TSM101I/AI
Temperature
Range
-20°C, +80°C
-40°C, +105°C
Package
N
•
•
D
•
•
N
DIP8
(Plastic Package)
D
SO8
(Plastic Micropackage)
PIN CONNECTIONS
(top view)
1
2
3
4
Vref
8
7
6
5
N =
Dual in Line Package (DIP)
D =
Small Outline Package (SO) - also available in Tape & Reel (DT)
June 2001
1/13
TSM101/A
ABSOLUTE MAXIMUM RATINGS
Symbol
V
CC
I
out
P
d
V
in
I
out
T
stg
T
j
T
thja
1.
2.
3.
Parameter
DC supply Voltage
1)
Output Current
2)
Power Dissipation
Input Voltage
3)
Input Current
Storage Temperature
Maximum Junction Temperature
Thermal Resistante Junction to Ambiant
Value
36
20
200
-0.3, V
CC
-1.5
±1
-40 to +125
150
130 to 200
Unit
V
mA
mW
V
mA
°C
°C
°C/W
All voltages values, except differential voltage are with respect to network ground terminal.
The voltage reference is not protected against permanent short circuit.
The magnitude of input and output voltages must never exceed -0.3V or VCC -1.5V.
OPERATING CONDITIONS
Symbol
V
CC
T
oper
Supply Voltage
Operating Free Air Temperature Range
Parameter
Value
4.5 to 32
T
max
to T
min
Unit
V
ELECTRICAL CHARACTERISTICS
T
amb
= 25°C, V
CC
= 15V (unless otherwise specified)
OPERATIONAL AMPLIFIER:
TSM101C/I/AC/AI
Symbol
I
CC
V
i
V
io
Total Supply Current
V
CC
= 1.5V
Input Voltage Range
Input Offset Voltage
25°C
T
min.
≤
T
amb
≤
T
max.
Input Bias Current
@ V
in
=1.2V on pin and V
in
=0V on pin 5
25°C
T
min.
≤
T
amb
≤
T
max.
Output Sink Current, V
ol
=2.5V
25°C
T
min.
≤
T
amb
≤
T
max.
Large Signal Voltage Gain
R
L
=2kΩ
T
min.
≤
T
amb
≤
T
max.
Supply Voltage Rejection Ratio
T
min.
≤
T
amb
≤
T
max.
Common Mode Rejection Ratio
T
min.
≤
T
amb
≤
T
max.
Gain Bandwith Product
V
cc
=15V, F = 100kHz
V
in
= 10mV, R
L
= 2kΩ, C
L
= 100pF
Output Leakage Current
25°C
T
min.
≤
T
amb
≤
T
max.
0
-5
-7
1
Parameter
Min.
Typ.
Max.
2
V
CC
- 1.5V
5
7
V
mV
nA
-700
-1000
-300
0
0
mA
15
8
V/m
V
90
80
1
dB
dB
Unit
mA
I
ib
I
sink
A
vo
15
65
SVR
CMR
GBP
MHz
I
o
2/13
2
7
µA
TSM101/A
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 resisto
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 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 32V DC)
Ground
Function
Voltage Reference Output 1.24V, 10mA max. Do not short circuit
OUTPUT
V
cc
GND
6
8
4
OUTPUT
INPUT
INPUT
4/13
APPLICATION NOTE
A BATTERY CHARGER USING THE TSM101
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-cadmi-
um 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
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 dif-
ference 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 regula-
tion of the output current of the SMPS and a pre-
cise 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 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.
A great majority of low or medium end power sup-
plies is voltage regulated by using shunt program-
mable voltage references like the TL431
(Figure 2).
5/13
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