Datasheet TSM101CN Specification

VOLTAGE AND CURRENT CONTROLLER

■ 1.24V SERIES VOLTAGE REFERENCE

WITH 10mA OUTPUT CURRENT AND 1%
PRECISION (TSM101A)

■ TWO OPERATIONAL AMPLIFIERS WITH

ORED OUTPUT AND 1MHZ GAIN BAND­WIDTH PRODUCT

■ BUILT-IN CURRENT GENERATOR WITH

ENABLE/DISABLE FUNCTION

■ 4.5 TO32V SUPPLY VOLTAGERANGE

■ SO8 AND DIP8 PACKAGES

DESCRIPTION

The TSM101/TSM101A integrated circuit incorpo­rates a high stability series band gap voltage refer­ence, 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.

TSM101/A

N

DIP8

(Plastic Package)

D

SO8

(Plastic Micropackage)

APPLICATIONS

This circuit is designed to be used in battery
chargers with a constant voltage and a limited out­put current.

It can be used in every types of application requir­ing a precision voltage regulation and current limi­tation.

Other applications include voltage supervisors,
over voltage protection...

ORDER CODE

Part Number

TSM101C/AC -20°C, +80°C ••
TSM101I/AI -40°C, +105°C ••

N=Dual in Line Package (DIP)
D=Small Outline Package (SO) - also available in Tape & Reel (DT)

June 2001

Temperature

Range

Package

ND

PIN CONNECTIONS (top view)

1

Vref

2

3

4

8

7

6

5

1/13

TSM101/A

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

T

T

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.

3. The magnitude of input and output voltages must never exceed -0.3V or VCC -1.5V.

DC supply Voltage

CC

I

out Output Current

P

Power Dissipation 200 mW

d

V

in Input Voltage

I

Input Current ±1mA

out

Storage Temperature -40 to +125 °C

stg

T

Maximum Junction Temperature 150 °C

j

Thermal Resistante Junction to Ambiant 130 to 200 °C/W

thja

OPERATING CONDITIONS

Symbol Parameter Value Unit

V

T

Supply Voltage 4.5 to 32 V

CC

Operating Free Air Temperature Range

oper

ELECTRICAL CHARACTERISTICS

T

=25°C, VCC= 15V (unless otherwise specified)

amb

1)

2)

3)

36 V
20 mA

-0.3, VCC-1.5

T

to T

max

min

V

OPERATIONAL AMPLIFIER: TSM101C/I/AC/AI

Symbol Parameter Min. Typ. Max. Unit

TotalSupply Current

I

CC

V

V

io

I

ib

I

sink

A

vo

SVR

CMR

GBP

I

o

i

V

= 1.5V

CC

Input Voltage Range 0
Input Offset Voltage

25°C
T

≤ T

amb

≤ T

max.

min.

Input Bias Current

@V

=1.2V on pin and Vin=0V on pin 5

25°C
T

min.

in

≤ T

amb

≤ T

max.

-700

-1000

Output Sink Current, Vol=2.5V

25°C

≤ T

T

min.

amb

≤ T

max.

Large Signal Voltage Gain

R

=2kΩ

L

≤ T

T

min.

amb

≤ T

max.

Supply Voltage Rejection Ratio

T

≤ T

amb

≤ T

max.

min.

Common Mode Rejection Ratio

T

≤ T

amb

≤ T

max.

min.

Gain Bandwith Product

V

=15V,F = 100kHz

cc

V

= 10mV, RL=2kΩ,CL= 100pF

in

Output Leakage Current

25°C
T

≤ T

amb

≤ T

max.

min.

-5

-7

-300 0

15

8

15

65 90

80

2

V

- 1.5V

CC

15

7

0

1 MHz

2
7

mA

V

mV

nA

mA

V/m

V

dB

dB

µA

2/13

ELECTRICAL CHARACTERISTICS

T

=25°C, VCC= 15V (unless otherwise specified)

amb

VOLTAGE REFERENCE : TSM101

Symbol Parameter

Reference Voltage

V

ref

I

= 1mA, Tamb =25°C

out

Temperature Stability

vt

K

T

min ≤Tamb ≤ Tmax 30 100 35 120

R

R

Load Regulation

eglo

1 < I
Line Regulation

egli

5

<

out

Vin<

< 10mA

32V

VOLTAGE REFERENCE : TSM101A

TSM101C TSM101I

Min. Typ. Max. Min. Typ. Max.

1.21 1.24 1.27 1.21 1.24 1.27

515 515

3.5 10 3.5 10

TSM101/A

Unit

V

ppm/°C

mV

mV

Symbol Parameter

Reference Voltage

V

ref

I

= 1mA, Tamb =25°C

out

Temperature Stability

vt

K

T

min ≤Tamb ≤ Tmax 30 100 35 120

R

R

Load Regulation

eglo

1 < I
Line Regulation

egli

5

<

out

Vin<

< 10mA

32V

CURRENT GENERATOR:TSM101, TSM101A

Symbol Parameter

I

Current Source 1.4 1.4 mA

o

Temperature Stability

K

cgt

T

min ≤Tamb ≤ Tmax 500 600

Line Regulation

C

glir

4.5 < V
Voltage at the enable pin to have

V

csen

Io = 1.4mA
T

Voltage at the enable pin to have

V

csdis

Io = 0mA
T

I

Input Current on the C

csen

T
Leakage Current

I

csleak

V

T

< 32V

cc

min ≤Tamb ≤ Tmax 0.6 0.6

min ≤Tamb ≤ Tmax 22

pin

min ≤Tamb ≤ Tmax

= 2V

cs

min ≤Tamb ≤ Tmax

sen

TSM101AC TSM101AI

Min. Typ. Max. Min. Typ. Max.

1.227 1.24 1.252 1.227 1.24 1.252

515 515

3.5 10 3.5 10

TSM101C/AC TSM101I/AI

Min. Typ. Max. Min. Typ. Max.

0.003 0.03 0.003 0.03

30 30

0.5 2 0.5 2

Unit

V

ppm/°C

mV

mV

Unit

ppm/°C

mA

V

V

µA

µA

3/13

TSM101/A

DESCRIPTION

Name Pin Type Function

V

ref

V

rin

C

rin

C

rref

C

sen

OUTPUT

V

cc

GND

1 OUTPUT Voltage Reference Output 1.24V, 10mA max. Do not short circuit
7 INPUT Voltage Regulation Loop input
5 INPUT Current Limitation Loop Input, connected to the sense resisto
3 INPUT Current Limitation Reference Input

Current source enable input. This current source can be used to offset the

2 INPUT

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.

6 OUTPUT

Output pin common to the voltage regulation and current limitation loops.

This output can drive the primary side (LED) of an optocoupler.
8 INPUT Power Supply Input (4.5 to 32V DC)
4 INPUT Ground

4/13

APPLICATION NOTE

A BATTERY CHARGER USING THE TSM101

This technical note shows how to use theTSM101
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

1

Vref

2

3

4

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 sup­plies is voltage regulated by using shunt program­mable voltage references like the TL431

(Figure 2).

8

7

6

5

The galvanic insulation of the control information
is done by using an opto-coupler in linear mode
with a variable photo current depending on thedif­ference 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 limita­tion loop use an internal 1.24V band-gap voltage
reference. This voltage reference has a good pre­cision (better than 1.5%) andexhibits avery stable
temperature behavior.

The current limitation isperformed by sensing the
voltage across the low ohmic value resistor R5
and comparing it to a fixed value set by the bridge
composed by R2and R3 (Figure 3).

When the voltage on R5 ishigher than the voltage
on R3 the output of the current loop operational
amplifier decreases. The optocoupler current in­creases 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.

5/13

TSM101/A

Figure 2 : SMPS Using a TL431 as Voltage Controller

The optocoupler current increases and tends to
reduce the output voltage by the way of the PWM
controller.

By enabling the TSM101 current source (pin 2) it
is possible to offset the current sensing by a volt­age equal to :

Voff # R4 * Io with Io= 1.4mA
This offset lowers the output charge current and
this function can be used to charge two types of

batteries having different capacities. The current
source is enabled by connecting pin 2 to ground

3 - CALCULATION OF THE ELEMENTS

The charge current is regulated at 700mA (if the
charge control input is left open) or 200mA (if the
charge control input is put to ground ), allowing the
charge of two different types of batteries.

3.1 - Voltagelimitation

The end-of- chargevoltage is limited at 1.45V/cell,
this is the recommended voltage for an ambient
temperature at 25oC.

A diode is generally inserted at the output of the
charger to avoid the discharge of the battery if the
charger is not powered. This diode is sometimes
directly integrated in the battery pack. The influ­ence of this diode on the charge is negligible if the
voltage drop (0.7V) is taken into account during
the design of the charger.

The voltage at the output of the charger is :

R6 R 7+

out

=

---------------------­R6

×

V

r

• V

and regarding R6 and R7 :

• R6=

------------------------------- -



Vout Vref–

R7×

Vref



P1, which is a part of R6 and R7 is not considered
in this equation.

The following values are used on the application
board :

• R7 = 12kΩ

• R6 = 1kΩ

• P1 = 220Ω, adjust for V

= 15.2V with the

output

battery replaced by a 1kΩ resistor

• R10 = short circuit

• C3 = 100nF

3.2 - Current regulation

R5 is the sense resistor used for current measure­ment.

The current regulation is effective when the volt­age drop across R5 is equal to the voltage on pin
5 of the TSM101 (assuming that the internal cur­rent source is disabled).

For medium currents (<1A), a voltage drop across
R5 of 200mV = Vr5 is a good value, R5 can be re­alized with standard low cost 0.5W resistors in
parallel.

• R5 = , R5 = 0.285Ω (four 1.2Ω resistor in
parallel)

Vr5

--------- ­Ich

R2 and R3 can be chosen using the following for­mula :

• R2 =

Vref Vr5–



R3

----------------------------

×



Vr5

CHARGE CONTROL

If the pin 2 is left open, the charge current is nom­inal at # 700mA.

6/13

TSM101/A

If pin2 is connected to ground, the internal current
source is enabled, the current measurement is
off-setted by a voltage equal to :

• Vr4 = Io x R4 withIo = 1.4mA
This can be used to lower the charging current or

eventually to stop the charge, if Vr4>V

r5

In our example, the current offset is equal to 700 ­200mA = 500mA, representing a voltage offset

Vr4 = 140mV across R4.
The following values are used on the application

board :

• R5 = 4 *1.2Ω 0.5W inparallel

• R4 = 100Ω

• R2 = 1.2kΩ

Figure 3 : SMPS Using the TSM101

• R3 = 220Ω

• R9 = short circuit

• R1 = 10kΩ

• C2 = 100nF

• C5 = 100nF

• C1 = output capacitor of the SMPS

• C4 = 10µF

4 - SCHEMATIC DIAGRAM

Figure 2 represents a schematic of the output cir­cuit of a “classical” SMPS using a TL431 for volt­age regulation. This circuit is modified to use
theTSM101 and the final circuit is represented in
figure 3.

5 - IMPROVEMENT

5.1. High frequency compensation

Two R-C devices (R9 + C2 & R10 + C3) are used
to stabilize the regulation at high frequencies.

The calculation of these values is not easy and is
a function of the transfer function of the SMPS.

A guess value for the capacitors C2 and C3 is
100nF.

5.2. Power supply for TSM101

In applications requiring low voltage battery
charge or when the chargeris in current regulation
mode, the output voltage can be too low to supply
correctly the TSM101.

The same problem occurs when the output is
short-circuited.

A solution to provide a quasi constant supply volt­age to theTSM101 is shown at figure 4 : an auxil-

iary winding is added at the secondary side of the
transformer.

This winding is forward coupled to the primary
winding, the voltage across it is directly propor­tional to the mainsrectified voltage, even if the fly­back voltage is close to zero.

As this auxiliary winding is a voltage source, it is
necessary to add a resistor (R11) on the cathode
of the rectifier (D3) to limit the current.

A low cost regulator (Q2 and Zener diode D4) is
used to power theTSM101. This is necessary with
autoranging SMPS with wide input voltages, for
example 90to240Vwithout switching. In standard
SMPS with voltage range from 200 to 240VAC or
100 to 130VAC, this regulator can be removed
and replacedby the small power supply shown on
figure 5 (Raux, Caux, D2).

7/13

TSM101/A

Figure 4 : An Auxiliary Winding for TSM101 Power Supply

5.3. Higher Precision for the Voltage Control

The voltage drop through the sense resistor R5
offsets the voltage measurement. In most battery
charging applications, this offset is not taken into
account because the error is negligeable com­pared to the end-of-charge voltage due to the fact

Figure 5 : Precise Output Voltage Control

that the charging current value decreases drasti­cally duringthe final phase of the battery charging.

But in other applications needing highest possible
precision in voltage control, another connecting
schematic is possible for TSM101 as shown on
figure 5.

In this schematic, the 0V reference is defined as
the common point betweenthe sense resistor, the
0V Output Voltage, the foot of the resistor bridge

8/13

R6/R7, and the ground (pin 4) of the TSM101.
TSM101A (1% internal voltage reference preci­sion) is required insuch applications.

TSM101/A

5.4. An example of application wherethe
charging current is different according to the
charging phase.

The following application includes a specific rec­ommendation which requires that the charging
current should be fixed to Ich1 = 800mA in normal
charging conditions, and Ich2 = 200mA when the
cell voltage is below Vl=2.5V to optimize the cell
life-time.

Moreover, an Charging Status LED should be
switched off when the cell voltage is above
Vh=6.5V.

Figure 6 shows how this can easily be achieved
using an additional dual comparator (type LM393)
where the first operator (C1) is used to activate the
TSM101 internal current generator to offset the
current measurement thanks to R4, and the sec­ond (C2) is used to switch the status LED off. On
figure 6, the status signal is determined by voltage
measurement, this could as well be achieved by
current measurement.

If V5 = 100mV is the maximum tolerable voltage
drop through the sense resistor R5 during normal
charging conditions, then the following calcula­tions apply :

Current Control :

R5 = V5 / Ich1 = 0.1 / 0.8 = 0.125
R5 = 125mΩ
V5 = V

and V

x R3 / (R2 + R3) with R2 + R3 ~ 12kΩ

ref

= 1.24V

ref

R3 = 1kΩ, R2 = 11.4kΩ
V5 = R4 x Io + R5 x Ich2, therefore, R4 = (V5 - R5

x Ich2) / Io with Io = 1.4mA
R4 = 53.6Ω
Vref = Vl x R15 / (R14 + R15) with Vl = 2.5V and

R14 + R15 ~ 20kΩ
R15 = R14 = 10kΩ
Voltage Control :
Vref = Vh x R6 / (R6 + R7) with Vh = 6.5V and
R6 + R7 ~ 12kW
R6 = 2.36kW, R7 = 10kW
Vref = Vh R17 / (R16 + R17)
R17 = 10kW, R16 = 42kW

Voltage Control :

Vref = Vh x R6 / (R6 + R7) with Vh = 6.5V and
R6 + R7 ~ 12kW
R6 = 2.36kW, R7 = 10kW
Vref = Vh R17 / (R16 + R17)
R17 = 10kW, R16 = 42kW

Figure 6 : Optimized Charging Conditions

9/13

EVALUATION BOARD -TECHNICAL NOTE

TSM101 integrates in the same 8 pin DIP or SO
package

• one 1.24V precision voltage reference

• two operationnal amplifiers

• two diodes which impose a NOR function on the

outputs of the operationnal amplifiers

• one current source which can be activated/ in-
hibited thanks to an external pin.
An immediate way to take advantage of the high
integration and reliability of TSM101 is to use it as
a voltage and current controller on power supplies
secondary. The application note AN896 describes
precisely how to use TSM101 in an SMPS battery
charger.

The TSM101 Evaluation Board is adaptable toany
power supply or battery charger (SMPS or linear)
as a voltage and current controller with minimal
constraints from the user.

HOW TO USE THE TSM101 EVALUATION
BOARD ?

The generic Electrical Schematic is shown on fig­ure 1. It represents an incomplete SMPS power
supply where the primary side is simplified.

Figure 1

The “IN+”and “IN-” power inputs of the evalua­tion board should be connected directly to the
power lines of the power supply secondary.

The “Vcc” input of the evaluation board should
be connected to the auxiliary supply line.

In the case of an SMPS power supply, the “Reg”
output of the evaluation board should be connect­ed to the Optocoupler input to regulate the PWM
block in the primary side. In the case of a linear
power supply, the “Reg” output should be con­nected to the base of the darlington to regulate the
power output.

A diode mightbe needed on the outputof the eval­uation board in the case of a battery charger appli­cation to avoid the discharge of the battery when
the charger is not connected.

COMPONENTS CALCULATIONS

The voltage control is given by the choice of the
resistor bridge R6/R7 (and the trimmer P1) due to
equation 1 :

• Vref = R6/(R6+R7)xVout eq1

where Vref = 1.24V

10/13

The current control is given by the choice of the
voltage drop through the sense resistor R5 (to be
linked to the nominal current of the application)
and bythe value of the sense resistor itself.

For medium currents (< 1A), a good value for the
voltage drop through R5 can be Vsense = 200mV
(dissipation < 200mW).

The resistor bridge R2/R3 should be chosen fol­lowing equation 2 :

• Vsense = R3/(R2+R3)xVref eq2

The total value of the resistor bridge should be in
the range of the kW in order to ensure a proper
charge for the voltage reference (in the range of
the mA).

To set the current limit, the sense resistor R5
should be chosen following equation 3 :

• Ilim = Vsense/R5 eq3

The internal current generator (Isce) can be used
to offset the current limitation with a lower value.

This current generator is activated by connecting
pin 2 to ground. It is inhibited ifpin 2 is connected
to the positive rail via the pull up resistor R1.

The current offset is given by the choice of there­sistor R4.

If Ilim1 is the current limit calculated in the previ­ous paragraph, and Ilim2 is the current limit that is
to be set when pin 2 is connected to ground, R4
should be chosen following equation 4 :

• R4 = (Vsense - Ilim2xR5)/Isce eq4

where Isce = 1.4mA
C4 andC5 are bypass capacitors used to smooth-

en the regulated outputs.
C2 andC3 are capacitors used for high frequency

compensation.

TSM101/A

Voltage/

Current
Control

R1 10kΩ 10kΩ 10kΩ
R2 1.2kΩ 1.2kΩ 1.2kΩ
R3 220kΩ 220kΩ 220kΩ
R4 100Ω 68Ω 68Ω
R5 1.2Ω x 4 0.8Ω x4 1Ωx1
R6 1kΩ 1kΩ 1kΩ
R7 12kΩ 8.2kΩ 5.6kΩ
P1 100Ω 100Ω 100Ω
2 straps 0Ω 0Ω 0Ω
C2 100nF 100nF 100nF
C3 100nF 100nF 100nF
C4 10µF22µF4.7µF
C5 100nF 100nF 100nF

Figure 2

15V
700mA
200mA

12V

1A

500mA

8.2V
200mA
100mA

EXAMPLES OF COMPONENT LISTS

Table 1 summerizes a few examples of compo­nent lists to generate quickly 15V/700mA/200mA,
12V/1A/500mA or 8.2V/200mA/100mA voltage
and current regulations.

11/13

TSM101/A

PACKAGE MECHANICAL DATA

8 PINS - PLASTIC DIP

Dim.

Min. Typ. Max. Min. Typ. Max.

A 3.32 0.131

a1 0.51 0.020

B 1.15 1.65 0.045 0.065
b 0.356 0.55 0.014 0.022

b1 0.204 0.304 0.008 0.012

D 10.92 0.430
E 7.95 9.75 0.313 0.384

e 2.54 0.100
e3 7.62 0.300
e4 7.62 0.300

F 6.6 0260

i 5.08 0.200
L 3.18 3.81 0.125 0.150
Z 1.52 0.060

Millimeters Inches

12/13

PACKAGE MECHANICAL DATA

8 PINS - PLASTIC MICROPACKAGE (SO)

TSM101/A

L

C

A

a2

b

e3

D

8

1

M

5

4

s

F

c1

a3

a1

E

b1

Millimeters Inches

Dim.

Min. Typ. Max. Min. Typ. Max.

A 1.75 0.069

a1 0.1 0.25 0.004 0.010
a2 1.65 0.065
a3 0.65 0.85 0.026 0.033

b 0.35 0.48 0.014 0.019

b1 0.19 0.25 0.007 0.010

C 0.25 0.5 0.010 0.020

c1 45° (typ.)

D 4.8 5.0 0.189 0.197
E 5.8 6.2 0.228 0.244
e 1.27 0.050

e3 3.81 0.150

F 3.8 4.0 0.150 0.157
L 0.4 1.27 0.016 0.050

M 0.6 0.024

S8°(max.)

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13/13