ZXSC100
SINGLE CELL DC-DC CONVERTER SOLUTION
ZXSC100
Document number: DS33613 Rev. 6 - 2
10 of 13
www.diodes.com
January 2012
© Diodes Incorporated
ZXSC100X8 Obsolete
Closest
lternative is ZXSC100N8
Designing with the ZXSC100 (cont.)
Main Switching Waveforms
Steady state operation under constant load gives an excellent indication of ZXSC100 performance. Represented in Figure 4.
is the main switching waveform, measured at the collector of Q1, indicating the transistor on-state and the diode energy
transfer to the output.
Fig. 4 Switching Waveform
Fig. 5 I
SENSE
Threshold
The peak switching current is derived from the threshold of the I
SENSE
pin and the sense resistor value (see Applications
section for calculations). Figure 5. shows the switching waveform associated with the I
SENSE
pin.
Shown in Figure 6. is the discontinuous inductor current. The ramp-up current stores energy in the inductor. The switching
transistor,Q1, is on during this time and has an equivalent current ramp-up, shown in Figure 7. The ramp-down current is
associated with the energy being delivered to the output via the Schottky diode, D1. The diode current is equivalent to this
ramp-down current and is shown in figure 8.
Fig. 6 Inductor Current (200mA/div)
Fig. 7 Transistor Current (200mA/div)
