M54646AP
Switching Characteristics
Switching Waveform
VMA – VMB or VMB – VMA
1
tOFF=0.69 • RT • CT
1/2
tON
tOFF
td
VE
VCH
Timing Chart
Two-phase
excitation
Phase 1
Phase 2
Application Directions
(1) Phase Input
Phase input determines output mode:
Phase
MA
MB
H
H
L
L
L
H
(2) VR (reference voltage)
Stepless current level variation is available by continuously changing VR.
(3) Current sensor
Compares voltage converted from amperage by current sensing resistor to designated reference voltage level. When
they are the same, comparator triggers Mono-stable, and shuts off output transistor during time frame tOFF. During
this period, current level decreases to slightly below reference level. When period has passed, output transistor is
reactivated. This series of operations is repeated.
(4) Single-pulse generator
Mono-stable is triggered at comparator output phase rise edge. Mono-stable output pulse width is determined by
input to timing terminals RT and CT, as follows:
tOFF = 0.69 × RT × CT
Rev.1.0, Sep.19.2003, page 4 of 8