STR83145
AND
STR84145
INTERIM ISSUE
(subject to change without notice)
August 16, 1994
Data Sheet
28190
LATCHED, UNIVERSAL
INPUT-VOLTAGE SWITCHES
Intended for power supplies with universal inputs (85 V to 265 V
rms), the STR83145 and STR84145 latched, universal input-voltage
switches incorporate timing, control, and drive circuitry with a high-
current triac (bidirectional triode thyristor) switch. Each device senses
the applied ac line potential and automatically switches the rectifier and
associated capacitors between a voltage-doubler configuration (for line
voltages to 141 V) and a full-bridge configuration (for line voltages
greater than 149 V). This eliminates the possibility of user error with
adjustable jumpers or switches. Also, the related switch-mode power
stage need operate only over a reduced range of dc input voltages
when compared with "wide input" power supplies using a bridge rectifier
only. The reduction in dc input voltage range permits the use of lower-
voltage capacitors and leads to a reduction in power stage stresses and
power dissipation. The STR83145 and STR84145 differ only in their
maximum ac current rating (10 A and 12 A, respectively).
The internal sensitive-gate triac is switched by a temperature-
compensated constant-current gate driver driven by a 15 kHz pulse
train to reduce power dissipation. The switch-over voltage is accurately
set during manufacture for consistent operation. An user-adjustable
delay is provided to ensure start-up in the full-bridge mode. Once
established (by an input voltage greater than 149 V rms), an integral
latch holds the full-bridge mode to preclude false application of the
doubler mode during brownouts, voltage droops, or missing cycles.
The requirements of low transient thermal impedance and steady-
state thermal resistance are satisfied in a molded, 5-lead single in-line
power package. Similar input-voltage switches, with a switch point of
159 V rms, are also available.
LATCH
2
1
3
4
MT1
Dwg. PK-005
ABSOLUTE MAXIMUM RATINGS
Repetitive Peak OFF-State Voltage,
V
DRM
.............................................
500 V
Static ON-State Current, I
T(RMS)
STR83145 ......................................
10 A
STR84145 ......................................
12 A
Non-Repetitive Surge ON-State Current, I
TSM
STR83145 ....................................
100 A
STR84145 ....................................
120 A
Package Power Dissipation,
P
D
........................................
See Graph
Triac Junction Temperature, T
J
.....
+125
°
C
Frame Temperature, T
M
................
+100
°
C
Operating Temperature Range,
T
A
...............................
-20
°
C to +125
°
C
Storage Temperature Range,
T
stg
.............................
-40
°
C to +125
°
C
COMMON
DELAY
GATE
MT2
5
OSC.
+
FEATURES
s
Low Duty Cycle Triac Drive for Minimum Dissipation
s
For Universal Input Operation Between 85 V rms and 265 V rms
to 10 A or 12 A
s
Internal Latch Prevents False Mode Switching
s
Internal Sensitive-Gate Power Triac
s
Adjustable Start-Up Delay
s
Accurate 145 V rms Switch-Point Voltage
s
Low External Parts Count
s
Low Power Dissipation
s
Low-Power External Parts
Always order by complete part number:
Part Number
STR83145
STR84145
Max. On-State Current
10 A rms
12 A rms
™
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
