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.

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