TSM114 Datasheet, PDF (12/14 Pages) STMicroelectronics – 3.3V 5V ±12V Housekeeping IC

TSM114
Housekeeping IC
4 Housekeeping IC
TSM114 is a one chip solution for all PC SMPS: it
integrates on one chip the Housekeeping Circuitry
(Over Voltage and Under Voltage protections,
with adequate sequencing).
Multiple Power Line Protection
The TSM114 Housekeeping Circuit is dedicated
to 3.3V, 5V and ±12V power lines protection. It
integrates a Precision Voltage Reference, a
multiple Over Voltage Protection Circuit and a
multiple Under Voltage Protection Circuit as well
as all the necessary logic and transient timing
management circuits for optimal and secure
communication with the motherboard, during start
up, switch off and stabilized conditions.
Over Voltage Protection
The Over Voltage Protection Circuit is made of
comparators with internal voltage thresholds
which do not require any external components for
proper operation. The outputs of these
comparators are ORed.
Under Voltage Protection
The Under Voltage Protection Circuit is made of
comparators with internal voltage thresholds
which do not require any external components for
proper operation. The outputs of these
comparators are ORed, and blanked by an
internal delay circuitry (Power Up Blanking - Tuv)
which can be adjusted with an external capacitor
(Cuv). This allows that during power up, the under
voltage protection circuit is inhibited.
Fault
The Over Voltage and Under Voltage Circuits
outputs are ORed before activating a latch. When
activated, this latch commands the full switch OFF
of the main power lines (3.3V, 5V, 12V) by an
external link between the housekeeping and the
primary PWM circuits via the main optocoupler or
any other device.
Power Good
The Under Voltage Circuits are Ored to switch the
Power Good output active (PG) to warn the
motherboard that the voltage of at least one of the
three power lines is out of range. The PG
activation bears an internal Tpg delay circuitry
which can be adjusted with an external capacitor
(Cpg).
Remote Control
Thanks to this information link to the motherboard,
a resetting signal to the latch is achievable with
the Remote pin (REM). When the Remote pin is
active, the external Fault link between
Housekeeping circuit and the PWM generator is
active (high = PWM OFF) and the PG pin is active
(high). Note that to reset effectively the latch, a
minimum width Remote pulse should be applied
thanks to an internal delay circuitry (Trem) which
can be adjusted with an external capacitor
(Crem).
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