
HA16129FPJ
5
Functional Description
This section describes the functions provided by the HA16129FPJ. See the section on formulas for details
on adjustment methods.
Regulator Block
Vout Voltage
This IC provides a stabilized 5V power supply by controlling the base current of an external transistor. The
largest current (the maximum CONT pin current) that can be drawn by the base of this external transistor is
20mA. Also note that the Vout output is also used for the power supply for this IC’s internal circuits.
Current Limiter Block
When a current detection resistor (R
CS
) is connected between the V
CC
pin and the CS pin, and the voltage
between these pins exceeds the V
CS
voltage (150mV Typ), the CONT pin function turns off and the output
voltage supply is stopped. This function can not work when V
OUT
< 2V.
Output Voltage (Vout) Adjustment
The output voltage can be adjusted by connecting an external resistor at the output voltage adjustment pin
(Voadj). However, if for some reason the voltage on this Vout line increases and exceeds the voltage
adjustment range (7V Max), the CONT pin function turns off and the output voltage supply is stopped.
Refer to the timing charts in conjunction with the following items.
LVI (Low Voltage Inhibit)
NMI
Detection Voltage
This function monitors for drops in the power-supply voltage. This function can be set up to monitor either
V
CC
or Vout. When Vout is monitored, a low level is output from the
NMI
pin if that voltage falls under the
detection voltage (4.63V Typ). Then, when the power-supply voltage that fell rises again, the
NMI
pin will
output a high level. Note that this function has a fixed hysteresis of 50mV (Typ). The monitored power
supply is selected by connecting the NMIsns pin either to the V
CC
pin or to the V
OUT
pin. When detecting
V
CC
, an external adjustment resistor is required.)
The detection voltage can also be adjusted with the NMIadj pin.
STBY
Detection Voltage
This function monitors for drops in the Vout voltage. It monitors the Vout voltage, and outputs a low level
from the
STBY
pin if that voltage drops below the detection voltage (3.0V Typ). Then, when the power-
supply voltage that fell rises again, the
STBY
pin will output a high level. Note that this function has a
fixed hysteresis of 1.35V (Typ).
The detection voltage can also be adjusted with the STBYadj pin.