M54646AP
Switching Characteristics
Switching Waveform
V
MA
– V
MB
or V
MB
– V
MA
t
OFF
=0.69 • R
T
• C
T
1
1/2
t
ON
t
OFF
t
d
VE
V
CH
Timing Chart
Two-phase
excitation
Phase 1
Phase 2
Application Directions
(1) Phase Input
Phase input determines output mode:
Phase
H
L
MA
H
L
MB
L
H
(2) V
R
(reference voltage)
Stepless current level variation is available by continuously changing V
R
.
(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 t
OFF
. 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 R
T
and C
T
, as follows:
t
OFF
= 0.69
×
R
T
×
C
T
Rev.1.0, Sep.19.2003, page 4 of 8
RENESAS [ RENESAS TECHNOLOGY CORP ]
