TSM1012
Low consumption voltage and current controller for battery chargers
and adapters
Datasheet - production data
Description
The TSM1012 is a highly integrated solution for
SMPS applications requiring the CV (constant
voltage) and CC (constant current) mode.
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TheTSM1012 device integrates one voltage
reference and two operational amplifiers (with
ORed outputs - common collectors).
Features
Constant voltage and constant current control
Low consumption
Low voltage operation
Low external component count
Current sink output stage
The voltage reference combined with one
operational amplifier makes it an ideal voltage
controller. The other operational amplifier,
combined with few external resistors and the
voltage reference, can be used as a current
limiter.
Figure 1. Pin connections (top view)
Easy compensation
High ac mains voltage rejection
Voltage reference
– Fixed output voltage reference 1.25 V
– 0.5% and 1% voltage precision
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Table 1. Order codes
Part number
Temperature range
TSM1012I
-40 to 105 °C
TSM1012AI
-40 to 105 °C
Package
D(1)
•
•
Vref (%)
Marking
1
M1012
0.5
M1012A
1. D = “Small Outline” package (SO) - also available in tape and reel (DT).
April 2016
This is information on a product in full production.
DocID10124 Rev 2
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www.st.com
Contents
TSM1012
Contents
1
Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3
Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5
Internal schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6
Principle of operation and application hints . . . . . . . . . . . . . . . . . . . . . 7
6.1
7
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6.1.1
Voltage control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1.2
Current control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.2
Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.3
Start-up and short-circuit conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.4
Voltage clamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1
8
Voltage and current control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
SO-8 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
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TSM1012
1
Pin descriptions
Pin descriptions
Table 2. SO-8 pinout
2
Name
Pin no.
Type
Function
VRef
1
Analog output
Voltage reference
CC-
2
Analog input
Input pin of the operational amplifier
CC+
3
Analog input
Input pin of the operational amplifier
CV-
4
Analog input
Input pin of the operational amplifier
CV+
5
Analog input
Input pin of the operational amplifier
GND
6
Power supply
Ground line. 0 V reference for all voltages.
OUT
7
Analog output
Output of the two operational amplifiers
VCC
8
Power supply
Power supply line
Absolute maximum ratings
Table 3. Absolute maximum ratings
Symbol
VCC
Vi
3
DC supply voltage
Value
Unit
DC supply voltage (50 mA =< ICC)
-0.3 V to Vz
V
Input voltage
-0.3 to VCC
V
Tstg
Storage temperature
-55 to 150
°C
Tj
Junction temperature
150
°C
Iref
Voltage reference output current
2.5
mA
ESD
Electrostatic discharge
2
kV
Rthja
Thermal resistance junction to ambient SO-8 package
175
°C/W
Operating conditions
Table 4. Operating conditions
Symbol
Parameter
Value
Unit
VCC
DC supply conditions
4.5 to Vz
V
Toper
Operational temperature
-40 to 105
°C
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Electrical characteristics
4
TSM1012
Electrical characteristics
Tamb = 25 °C and VCC = +18 V (unless otherwise specified).
Table 5. Electrical characteristics
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
180
µA
Total current consumption
ICC
Total supply current, excluding current in
voltage reference(1).
VCC = 18 V, no load
Tmin. < Tamb < Tmax.
100
Vz
VCC clamp voltage
ICC = 50 mA
28
V
Operators
Vio
Input offset voltage
TSM1012
Tamb = 25 °C
Tmin. Tamb Tmax.
Tamb = 25 °C
Tmin. Tamb Tmax.
TSM1012A
DVio
1
0.5
Input offset voltage drift
4
5
2
3
mV
V/°C
7
Iio
Input offset current
Tamb = 25 °C
Tmin. Tamb Tmax.
2
30
50
nA
Iib
Input bias current
Tamb = 25 °C
Tmin. Tamb Tmax.
20
50
150
200
nA
SVR
Supply voltage rejection ration
VCC = 4.5 V to 28 V
Vicm
Input common mode voltage range
CMR
Common mode rejection ratio
65
100
0
Tamb = 25 °C
Tmin. Tamb Tmax.
70
60
0.5
dB
VCC -1.5
85
V
dB
Output stage
Gm
Transconduction gain. sink current only(2)
Tamb = 25 °C
Tmin. Tamb Tmax.
Vol
Low output voltage at 5 mA sinking current
Tmin. Tamb Tmax.
Ios
Output short-circuit current. Output to (VCC
- 0.6 V). Sink current only.
Tamb = 25 °C
Tmin. Tamb Tmax.
1
1
250
6
5
mA/mV
400
10
mV
mA
Voltage reference
Vref
Reference input voltage
TSM1012 1% precision
Tamb = 25 °C
Tmin. Tamb Tmax.
Tamb = 25 °C
Tmin. Tamb Tmax.
TSM1012A 0.5% precision
Vref
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Reference input voltage deviation over the
temperature range
Tmin. Tamb Tmax.
DocID10124 Rev 2
1.238 1.25
1.225
1.244 1.25
1.237
20
1.262
1.273
1.256
1.261
V
30
mV
TSM1012
Electrical characteristics
Table 5. Electrical characteristics (continued)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
RegLine
Reference input voltage deviation over the VCC Iload = 1 mA
range.
20
mV
RegLoad
Reference input voltage deviation over the
output current.
10
mV
VCC = 18 V,
0 < Iload < 2.5 mA
1. Test conditions: pin 2 and 6 connected to GND, pin 4 and 5 connected to 1.25 V, pin 3 connected to 200 mV.
2. The current depends on the difference voltage between the negative and the positive inputs of the amplifier. If the voltage on
the minus input is 1 mV higher than the positive amplifier, the sinking current at the output OUT will be increased by
Gm x 1 mA.
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Internal schematics
5
TSM1012
Internal schematics
Figure 2. Internal schematic
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Figure 3. Typical adapter or battery charger application using TSM1012
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In the application schematic shown in Figure 3, the TSM1012 device is used on the
secondary side of a flyback adapter (or battery charger) to provide accurate control of the
voltage and current. The above feedback loop is made with an optocoupler.
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TSM1012
Principle of operation and application hints
6
Principle of operation and application hints
6.1
Voltage and current control
6.1.1
Voltage control
The voltage loop is controlled via a first transconductance operational amplifier, the resistor
bridge R1, R2, and the optocoupler which is directly connected to the output.
The relation between the values of the R1 and R2 should be chosen as written in Equation 1.
Equation 1
R1 = R2 x Vref / (Vout - Vref)
Where Vout is the desired output voltage.
To avoid the discharge of the load, the resistor bridge R1, R2 should be highly resistive. For
this type of application, a total value of 100 K (or more) would be appropriate for the
resistors R1 and R2.
As an example, with R2 = 100 K, Vout = 4.10 V, Vref = 1.210 V, then R1 = 41.9 K.
Note:
If the low drop diode should be inserted between the load and the voltage regulation resistor
bridge to avoid current flowing from the load through the resistor bridge, this drop should be
taken into account in Equation 1 by replacing Vout by (Vout + Vdrop).
6.1.2
Current control
The current loop is controlled via the second transconductance operational amplifier, the
sense resistor Rsense, and the optocoupler.
The Vsense threshold is achieved externally by a resistor bridge tied to the Vref voltage
reference. Its middle point is tied to the positive input of the current control operational
amplifier, and its foot is to be connected to the lower potential point of the sense resistor as
shown in Figure 4. The resistors of this bridge are matched to provide the best precision
possible.
The control equation verifies:
Equation 2
Rsense x Ilim = Vsense
Vsense = R5 x Vref / (R4 + R5)
Equation 3
Ilim = R5 x Vref / (R4 + R5) x Rsense
where Ilim is the desired limited current, and Vsense is the threshold voltage for the current
control loop.
Note that the Rsense resistor should be chosen taking into account the maximum dissipation
(Plim) through it during the full load operation.
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Principle of operation and application hints
TSM1012
Equation 4
Plim = Vsense x Ilim
Therefore, for most adapter and battery charger applications, a quarter-watt, or half-watt
resistor to make the current sensing function is sufficient.
The current sinking outputs of the two transconductance operational amplifiers are common
(to the output of the IC). This makes an ORing function which ensures that whenever the
current or the voltage reaches too high values, the optocoupler is activated.
The relation between the controlled current and the controlled output voltage can be
described with a square characteristic as shown in the following V/I output-power graph.
Figure 4. Output voltage versus output current
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6.2
Compensation
The voltage control transconductance operational amplifier can be fully compensated. Both
of its output and negative input are directly accessible for external compensation
components.
An example of a suitable compensation network is shown in Figure 6. It consists of
a capacitor Cvc1 = 2.2 nF and a resistor Rcv1 = 22 K in series.
The current control trans conductance operational amplifier can be fully compensated. Both
of its output and negative input are directly accessible for external compensation
components.
An example of a suitable compensation network is shown in Figure 6. It consists of
a capacitor Cic1 = 2.2 nF and a resistor Ric1 = 22 K in series.
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TSM1012
6.3
Principle of operation and application hints
Start-up and short-circuit conditions
Under start-up or short-circuit conditions the TSM1012 device is not provided with a high
enough supply voltage. This is due to the fact that the chip has its power supply line in
common with the power supply line of the system.
Therefore, the current limitation can only be ensured by the primary PWM module, which
should be chosen accordingly.
If the primary current limitation is considered not to be precise enough for the application,
then a sufficient supply for the TSM1012 device has to be ensured under any condition. It
would then be necessary to add some circuitry to supply the chip with a separate power line.
This can be achieved in numerous ways, including an additional winding on the transformer.
6.4
Voltage clamp
Figure 6 shows how to realize a low-cost power supply for the TSM1012 device (with no
additional windings). Please pay attention to the fact that in the particular case presented
here, this low-cost power supply can reach voltages as high as twice the voltage of the
regulated line. Since the absolute maximum rating of the TSM1012 supply voltage is 28 V.
In the aim to protect he TSM1012 device against such high voltage values an internal Zener
clamp is integrated.
Equation 5
Rlimit = (VCC - Vz) x Ivz
Figure 5. Clamp voltage
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Principle of operation and application hints
TSM1012
Figure 6. Typical application schematic
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7
Package information
Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK is an ST trademark.
7.1
SO-8 package information
Figure 7. SO-8 package outline
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Package information
TSM1012
Table 6. SO-8 package mechanical data
Dimensions (mm)
Symbol
Min.
Typ.
A
Max.
1.75
A1
0.10
A2
1.25
b
0.28
0.48
c
0.17
0.23
(1)
4.80
4.90
5.00
E
5.80
6.00
6.20
E1(2)
3.80
3.90
4.00
D
e
0.25
1.27
h
0.25
0.50
L
0.40
1.27
L1
k
1.04
0°
ccc
8°
0.10
1. Dimension “D” does not include mold flash, protrusions or gate burrs. Mold flash, protrusions or gate burrs
shall not exceed 0.15 mm in total (both sides).
2. Dimension “E1” does not include interlead flash or protrusions. Interlead flash or protrusions shall not
exceed 0.25 mm per side.
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Revision history
Revision history
Table 7. Document revision history
Date
Revision
01-Feb-2004
1
Initial release.
2
Removed Mini SO-8 package from the whole document.
Updated Section 7: Package information on page 11
(replaced Figure 7 on page 11 by new figure, updated
Table 6 on page 12).
Minor modifications throughout document.
15-Apr-2016
Changes
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TSM1012
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