Datasheet

Internal to UCC24610D:
Minimum TON time
Minimum TOFF time
Detailed Installation Instructions for use of SR Demonstration Board www.ti.com
3 Detailed Installation Instructions for use of SR Demonstration Board
The SR Demonstration Board is pre-programmed for:
1. T
ON
= ~1ms using 66.5 kΩ, and
2. T
OFF
= ~5.5 µs using 154 kΩ.
Adjust T
ON
and T
OFF
resistor values for your system board by the following procedure:
1. Observe the ringing at turn-on of the schottky diode during the flyback period under maximum-load,
low-line conditions. Measure the time it takes for this ringing to dampen completely. Set the initial T
ON
resistance so that the T
ON
time is equal to the complete dampening time.
2. Observe the resonant ringing at turn-off of the schottky diode after the flyback period under
maximum-load, high-line conditions. Measure the period of this resonant ringing, and set the initial T
OFF
resistance so that the T
OFF
time is equal to the resonant period.
These resistances can be re-adjusted later for optimal performance after observing SR waveforms under
all of the various operational conditions with the Demonstration board in place. See UCC24610 datasheet
for T
ON
and T
OFF
design information and resistance selection.
Attach VS “pin” to ground-referenced anode pad of existing schottky diode.
Attach VD “pin” to cathode pad of existing schottky diode.
Attach VCC “pad” to 5-V output node of system board with a short piece of flexible wire.
4 DCM Applications
For DCM applications, the system board may now be powered up and operation evaluated.
Figure 4. DCM Example Waveforms With Internal T
ON
and T
OFF
Timing
4
UCC24610EVM-693 Secondary-Side Synchronous Rectifier Controller Diode SLUU450–September 2010
Replacement Demonstration Board
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