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SLUS557B − MARCH 2003 − REVISED APRIL 2004
The circuit for the UC28025 shown in Figure 15 describes achievement a constant volt-second product clamp
over varying input voltages. The ramp generator components, R and C are chosen so that the ramp at Pin
T
R
9 (ILIM/SD) crosses the 1-V threshold at the same time the desired maximum volt-second product is reached.
The delay through the functional inverter block must be such that the ramp capacitor can be completely
discharged during the minimum deadtime.
UC28025
VIN
OUTB
RT
14
ILIM/SD
9
OUTA
11
CR
UDG−03050
Figure 15. Achieving Constant Volt-Second Product Clamp with the UC28025
13
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