APL5606 Anpec Electronics Corporation, APL5606 Datasheet - Page 8

• Manufacturer Part Number: APL5606
• Description: Low Dropout 600ma Linear Regulator For Dc Fan Control
• Manufacturer: Anpec Electronics Corporation

Under-Voltage Lock-Out (UVLO)
The APL5606 has a built-in under-voltage lock-out circuit
to keep the output off until the internal circuitry is operat-
ing properly. The UVLO function initiates a soft start pro-
cess after input voltage exceeds its rising UVLO thresh-
old during power on. Typical UVLO threshold is 2.5V with
0.15V hysteresis.
Soft-Start
The APL5606 provides an internal soft-start circuitry to
control rise rate of the output voltage and limit the cur-
rent surge during start-up. Approximate 20 s delay time
after the V
soft-start. The typical soft-start interval is about 130 s.
Adjustable/Full Speed Mode Selection
The APL5606 features an input pin to select one of the
operation modes for DC fan speed control. In adjustable
mode, the output voltage follows the 1.6 times of the volt-
age on VSET pin to dynamically adjust the DC fan speed;
in full speed mode, the internal P-channel MOSFET fully
turns on to drive the DC fan with maximum supply voltage
(V
age at high level(V
justable mode; driving the FSM at low level(V
sets the IC to operate in full speed mode. The FSM is
pulled low by an internal resistor.
Current Limit
The APL5606 provides a current limit circuitry, which
monitors the output current and controls P-MOS’ s gate
voltage to limit the output current at 700mA (min.).
Foldback Current Limit
When the output voltage drops below 0.6V (typical), which
is caused by over load or short circuit, the foldback cur-
rent limit circuitry limits the output current to 250mA. The
foldback circuit current limit is used to reduce the power
dissipation during short circuit condition. The foldback
current limit is disabled for 0.6ms (typical) after the UVLO
threshold is reached, so that the IC has normal 700mA
(min.) current limit level during start-up.
Copyright
Rev. A.2 - Jan., 2008
Function Descriptions
APL5606
IN
-V
DROP
) for full speed operation. Driving the FSM volt-
IN
is over the UVLO threshold, the IC starts a
ANPEC Electronics Corp.
FSM
>1.6V) sets the IC to operate in ad-
FSM
<0.4V)
8
Thermal Shutdown
A thermal shutdown circuit limits the junction temperature
of APL5606. When the junction temperature exceeds
+150 C, the thermal shutdown circuitry disables the
output, allowing the device to cool down. The output
circuitry is enabled again after the junction tempera-
ture cools down by 40 C, resulting in a pulsed output
during continuous thermal overload conditions. The ther-
mal protection is designed to protect the IC in the event
of over temperature conditions. For reliable operation,
the junction temperature cannot exceed T
www.anpec.com.tw
J
=+125 C.