TS1051
Constant Voltage and Constant Current Controller
For Battery Chargers and Adaptors
SOT-26
Pin Definition:
1. V
CTRL
6. V
CC
2. V
ND
5, V
SENSE
3. Out
4. I
CTRL
SOP-8
Pin Definition:
1. V
CTRL
8. V
ND
2. V
CC
7, Out
3. V
SENSE
6. I
CTRL
4. N.C
5. N.C
General Description
TS1051 is a highly integrated solution for SMPS applications requiring CV (constant voltage) and CC (constant current)
mode. TS1051 integrated one voltage reference, two operational amplifiers, and a current sensing circuit. The voltage
reference combined with one operational amplifier make it an ideal voltage controller, and the other low voltage
reference combined with the other operational amplifier make it an ideal current limiter for output low side current
sensing.
The current threshold is fixed, and precise. The only external components are:
* A resistor bridge to be connected to the output of the power supply (Adapter, battery charger) to set the voltage
regulation by dividing the desired output voltage to match the internal voltage reference value.
* A sense resistor having a value and allowable dissipation power which need to be chosen according to the internal
voltage threshold.
Features
●
●
●
●
●
●
●
Constant Voltage and Constant Current Control
Low Voltage Operation
Precision Internal Voltage Reference
Low External Component Count
Current Sink Output Stage
Easy Compensation
Low AC Mains Voltage Rejection
Ordering Information
Part No.
TS1051CX6 RF
TS1051CS RL
Package
SOT-26
SOP-8
Packing
3Kpcs / 7” Reel
2.5Kpcs / 13” Reel
Block Diagram
Application
●
●
Battery Charger
Adapters
Pin Function Description
Name
V
CTRL
V
ND
Out
I
CTRL
V
SENSE
V
CC
Type
Analog Input
Power Supply
Current Sink Output
Analog Input
Analog Input
Power Supply
Function
Input Pin of the Voltage Control Loop
Ground Line. 0V Reference For All Voltage
Output Pin. Sinking Current Only
Input Pin of the Current Control Loop
Input Pin of the Current Control Loop
Position Power Supply Line
1/9
Version: B07
TS1051
Constant Voltage and Constant Current Controller
For Battery Chargers and Adaptors
Absolute Maximum Rating
Parameter
DC Supply Voltage
Input Voltage
Operating Temperature
Maximum Junction Temperature Range
Thermal Resistance Junction to Ambient
SOP-8
SOT-26
Symbol
V
CC
V
IN
T
OP
T
J
Rθja
Value
14
-0.3 to V
CC
0 to +85
150
130
250
Unit
V
V
o
o
o
o
C
C
C/W
C/W
Operating Condition
Parameter
DC Supply Voltage
Symbol
V
CC
Value
2.5 to 12
Unit
V
Electrical Specifications
(Ta=25
o
C, V
IN
=5V unless otherwise noted)
Parameter
Total Current Consumption
Total Supply Current – not taking the output sinking current into
account
Voltage Control Loop
Trans-conduction Gain (Vctrl) sink Current Only (Note 1)
Voltage Control Loop Reference (Note 2)
Input Bias Current (Vctrl)
Current Control Loop
Trans-conduction Gain (Ictrl) sink Current only (Note 3)
Current Control Loop Reference, (Note 4) I
OUT
=2.5A,
Current Out of Pin Ictrl at – 200mV
Output Stage
Low Output Voltage at 10mA sinking Current
Output Short Circuit Current. Output to V
CC.
Sink Current Only
V
OL
I
OS
--
--
200
27
--
50
mV
mA
G
MI
V
SENSE
I
IBI
1.5
196
--
7
200
25
--
204
--
mA/mV
mV
µA
G
MW
V
REF
I
IBV
1
1.198
--
3.5
1.21
50
--
1.222
--
mA/mV
V
nA
I
CC
--
1.1
2
mA
Symbol
Min
Typ
Max
Unit
Note:
1: If the Voltage on Vctrl (the negative input of the amplifier) is higher than the positive amplifier input (Vref-1.21V), and
it is increased by 1mV, the sinking current at the output will be increased by 3.5mA.
2: The internal Voltage reference is set at 1.21V (bandgap reference). The voltage control loop precision takes into
account the cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the
trans-conductance operational amplifier. The internal voltage reference is fixed by bandgap, and trimmed to 0.5%
accuracy at room temperature.
3: When the positive input at Ictrl is lower than -200mV, and the voltage is decreased by 1mV, the sinking current
at the output will be increased by 7mA
4: The internal current sense threshold is set to -200mV. The current control loop precision takes into account the
cumulative effects of the internal voltage reference deviation as well as the input offset voltage of the
trans-conduction operational amplifier
2/9
Version: B07
TS1051
Constant Voltage and Constant Current Controller
For Battery Chargers and Adaptors
Typical Adapter or Battery Charger Application Circuit
* In the above application schematic, the TS1051 is used on the secondary side of a fly-back adapter (or battery
charger) to provide an accurate control of voltage and current. The above feedback loop is made with an optocoupler.
Principle of Operation and Application Hints
Voltage Control
The voltage loop is controlled via a first trans-conductance operational amplifier, the resistor bridge R1, R2, and the
optocoupler which is directly connected to the output.
The relation between the values of R1 & R2 should be chosen as following:
*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 100KΩ (or more) would be appropriate for the resistors R1 & R2. As an example, with R2=100KΩ,
Vout=4.10V, Vref=1.21V, then R1=41.9KΩ.
Note that 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 into the above
calculations by replacing Vout by (Vout + Vdrop).
3/9
Version: B07
TS1051
Constant Voltage and Constant Current Controller
For Battery Chargers and Adaptors
Principle of Operation and Application Hints (continues)
Current Control
The current loop is controlled via the second trans-conductance operational amplifier, the sense resistor Rsense, and
the optocoupler. The control verifies as following
* Rsense x llim = Vsense
* Rsense = Vsense / llim
Ilim is the desired limited current, Vsense is the threshold voltage for the current control loop.
As an example, with llim = 1A, Vsense = -200mV, then Rsense = 200mΩ.
Note that the Rsense resistor should be chosen taking into account the maximum dissipation (Plim) through it during
full load operation.
* Plim = Vsense x llim
As an example, with llim=1A, and Vsense=200mV, Plim=200mW.
Therefore, for most adapter and battery charger applications, a quarter-watt, or half-watt resistor to make the current
sensing function is sufficient.
Vsense threshold is achieved internally 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 lower potential point of
the senseresistor as shown on the following figure. The resistors of this bridge are matched to provide the best
precision possible. The current siking outpits of the two trans-conductance operational amplifiers are common (to the
outpit 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
Output Voltage vs. Output Current
4/9
Version: B07
TS1051
Constant Voltage and Constant Current Controller
For Battery Chargers and Adaptors
Principle of Operation and Application Hints (continues)
Compensation
The voltage control trans-conductance operational amplifier can be fully compensated. Both of its output and negative input are
directly accessible for external compensation components.
And example of a suitable compensation network is shown in typical application circuit. It consists of a capacitor Cvc1=2.2nF and a
resistor Rcv1=470KΩ in series, connected in parallel with another capacitor Cvc2=22pF.
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 suitable compensation network is shown in typical
application circuit. It consists of a capacitor Cic1=2.2nF and resistor Ric1=22KΩ in series. When the Vcc voltage reaches 12V it
could be interesting to limit the current coming through the output in the aim to reduce the dissipation of the device and increase the
stability performances of the whole application. An example of suitable Rout value could be 330Ω in series with the optocoupler in
case Vcc=12V.
Start Up and Short Circuit Conditions
The TS1051 is not provided with a high enough supply voltage in under start-up or short-circuit conditions. 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 TS1051 has
to be ensured under any condition. It would then be necessary to add some circuitry to supply the chip with separate
power line. This can be achieved in numerous ways, including an additional winding on the transformer. The following
schematic shows how to realize a low-cost power supply for the TS1051 (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 TS1051 supply voltage is 14V, this
low-cost auxiliary power supply can only be used in applications where the regulated line voltage does not exceed 7V.
5/9
Version: B07
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