TS1051

Constant Voltage and Constant Current Controller

For Battery Chargers and Adaptors

5/8

Version: C07

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.