Rev0.7 May. 29, 2009(LF)

Technology

FS211F

Darlington-pair Transistor Output

The figure 6 is the circuit diagram of Darlington-pair transistor. Under the heavy current loading,

the power loss of the high saturation voltage can be calculated into the following formula:

According to the IC package and the curve of the power loss, the Pc should be applied to and

within the safety value.

30V is the voltage of Zener breakdown diode. However, if the voltage, excluding that of the

power supply, is more than 30V under the long-time operation, the diode will be destroyed.

2,3

Q2

+

_

+

_

V

B E

V

CE(SAT)

Q1

Fig. 6 Darlington-pair Transistor Output