AT1382A
Preliminary Product Information
4-Channel DC-DC Converter for DSC
Function Description
1. Power Converter Functions
•Reference voltage block
The reference voltage circuit generates a temperature independence voltage (typical = 0.9V) from
the power source, which is used as reference voltage for the IC’s internal circuitry and supply load
current above 1mA to external device.
•Triangular oscillator block
The triangular wave oscillator is generated by timing resistor (RT) and timing capacitor(CT) to
incorporate each other. The waveforms CT (amplitude of 0.3V to 0.7V), CT1 (amplitude 0.25V
to 0.65V in phase with CT) and CT2 (amplitude 0.25V to 0.65V in inverse phase with CT) are
input to the PWM comparator.
•Error amplifier block
The error amplifier outputs controlling error signal to PWM comparator from sensing DC/DC
converter output voltage. In addition , an arbitrary loop gain can be set by connecting feedback
resistor and capacitor from the output pin to inverted input pin of the error amplifier, in order to
make a stable phase compensation to the system.
•PWM comparator block
The PWM comparator is a voltage-to-pulse width converter for controlling the duty cycle of
DC/DC converter.
Channels 1and 2 main sides, channel 3 and 4 : The comparator keeps the output transistor turn on
while the error amplifier output voltage and DTC voltage still higher than the triangular wave
voltage.
Channels 1 and 2 synchronous rectification sides : The comparator keeps the output transistor turn
on while the error amplifier output voltage still lower than the triangular wave voltage.
•Output block
The output block is the totem pole configuration , which could drive external MOSFET or
transistor.
•Battery low detect block
The AT1382A battery-low comparator open-drain output LBO sinks up to 1mA if the LBI input is
below its threshold voltage. Connect LBO to power source with a 100K~1MΩ pullup resistor.
•Analog gain block
The AT1382A analog gain block is a voltage amplifier with a gain of 100 and a push-pull output
stage with 2mA drive capability. The analog gain block can be used with an external P-channel
MOSFET pass transistor to build a low-dropout linear regulator. Connect ENLD to High to enable
the gain block.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
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AIMTRON [ AIMTRON TECHNOLOGY ]
