ICE3AR1580VJZ Datasheet, PDF (15/43 Pages) Infineon Technologies AG – Of f -Line SMPS Cur rent Mode Cont rol ler wi th integrated 800V

CoolSET™ F3R80
ICE3AR1580VJZ
Functional Description
In the Startup Phase, the IC provides a Soft Start period to control the primary current by means of a duty cycle
limitation. The Soft Start function is a built-in function and it is controlled by an internal counter.
Figure 11: Soft Start Phase
When the V_VCC exceeds the on-threshold voltage, the IC starts the Soft Start mode (Figure 10).
The function is realized by an internal Soft Start resistor, a current sink and a counter. And the amplitude of the
current sink is controlled by the counter (Figure 12).
5V
SoftS
R_SoftS
Soft Start ^{32I 8I 4I 2I I}
Counter
Figure 12: Soft Start Circuit
After the IC is switched on, the V_SoftS voltage is controlled such that the voltage is increased step-wisely (32
steps) with the increase of the counts. The Soft Start counter would send a signal to the current sink control in
every 300µs such that the current sink decrease gradually and the duty ratio of the gate drive increases
gradually. The Soft Start will be finished in 10ms (t_Soft-Start) after the IC is switched on. At the end of the Soft Start
period, the current sink is switched off.
Within the soft start period, the duty cycle is increasing from zero to maximum gradually (see Figure 13).
Data Sheet
15
V2.0, 2014-01-20