TS1051

Constant Voltage and Constant Current Controller

For Battery Chargers and Adaptors

3/9

Version: B07

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).