7 / 18 page

C2472, C2473 and C2474
Datasheet
RDFC Controllers for Offline Applications
Product data
Page 7 of 18
DS-1423-0709C
© Cambridge Semiconductor Ltd 2007
26-Sep-2007
Switching Waveforms
The collector voltage (VCE) and current (IC) waveforms of the primary switching transistor (Q1 in Figure 3) are
shown in Figure 6. TRES is the duration of the transformer resonance during the off period. Note that in
Overload mode, the primary switch Q1 is turned off when the current exceeds the protection level OCPH
(sensed by the CS pin voltage).
Figure 6: Typical Switch (Q1) Collector Voltage (VCE) and Current (IC) Waveforms