4
IR2172
ADVANCE INFORMATION
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Application Hint:
Temperature drift of the output carrier frequency can be cancelled by measuring both a PWM period and
the on-time of PWM (Duty) at the same time. Since both periods vary in the same direction, computing the
ratio between these values at each PWM period gives consistent measurement of the current feedback
over the temperature drift.
AC Electrical Characteristics cont.
V
CC
= V
BS
= 15V, unless otherwise specified.
Symbol Definition Min. Typ. Max. Units Test Conditions
Proagation delay characteristics
tdoc Propagation delay time of OC 1 1.5 —
twoc Low true pulse width of OC — 1 —
µsec
Vin+= -260mV
Vin- = 0V
Vin+= +260mV
Vin- = 0V
Duty=93%
Duty=7%
Carrier Frequency =
40kHz
PO
PO
Timing Waveforms
Figure 1 Output waveform
