Product Specification
Power Supply Supervisor + Regulator + PWM
SG6105A
signal in the secondary power transformer is proportional
to the AC line voltage. Adjust the ratio of resistor divider
Negative Voltage Protection (NVP)
to decide the threshold of power-down warning. A small The NVP provides an under-voltage protection (UVP)for
capacitor is connected from UVAC to ground for filtering negative voltage outputs. An under-voltage represents the
the switching noise.
phenomenal of the overload condition in negative voltage
output. For example, the –12V output may drop to –10V
during the overload situation. A resistor determining the
threshold of the protection is connected from pin NVP to the
negative voltage output. Via this resistor, NVP outputs a
64µA constant current to the negative voltage output. When
the NVP voltage is over 2.1V and the situation kept for
longer than 7ms, 6105A locks the power outputs off:
VNVP = 64µA × (R1 + R2) – V-12V
(1)
The poweroutputsare locked offwhenVNVP
≥
2
.
1
V
.
Over-Power Protection (OPP)
The OPP (over-power protection) is used for detecting
over-power and/or short-circuit conditions. When OPPS
voltage (p.4, Note-1) is higher than 2.1V and this situation
exists for longer than 7ms, 6105A pulls the PG low and
locks off the power outputs.
© System General Corp.
Version 1.0.1 (IAO33.0072.B0)
- 14 -
www.sg.com.tw
•
www.fairchildsemi.com
September 25, 2007
FAIRCHILD [ FAIRCHILD SEMICONDUCTOR ]
