STR83145
LATCHED, UNIVERSAL
INPUT-VOLTAGE SWITCHES
Intended for power supplies with universal inputs (85 V to 265 V
rms), the STR83145 latched, universal input-voltage switch incorpo-
rates timing, control, and drive circuitry with a high-current triac
(bidirectional triode thyristor) switch. The 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 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. A 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.
Data Sheet
28190A
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)
............................................
10 A
Non-Repetitive Surge ON-State Current,
I
TSM
...............................................
100 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
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, e.g.,
STR83145 .
™
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