SEA05

Compensation

Doc ID 17014 Rev 1

7/10

reference. Its middle point is tied to the positive input of the current control operational

amplifier, and its foot has to be connected to lower potential point of the sense resistor as

shown in Figure 4. The resistors of this voltage divider are matched to provide the best

possible precision. The current sinking outputs of the two trans-conductance 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.

(with power supply of the device independent from the output voltage)

Figure 5.

Output voltage versus output current

7

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 as shown in Figure 4.

V

Io

Voltage regulation

Current regulation

(Vcc of the device independent from output voltage)

Vo

Io

Voltage regulation

Current regulation

(Vcc of the device independent from output voltage)