STR84145 Datasheet, PDF (1/8 Pages) Allegro MicroSystems – LATCHED, UNIVERSAL INPUT-VOLTAGE SWITCHES

STR83145 AND
STR84145
INTERIM ISSUE
(subject to change without notice)
August 16, 1994
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
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.
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 Max. On-State Current
STR83145 10 A rms
STR84145 12 A rms
™