AT1396A/B/C/D
Preliminary Product Information
6-Channel DC-DC Converter for DSC
Application Information
The AT1396A/B/C/D include 6 channels DC/DC to generate a multiple-output digital
camera power-supply system. It include:
z
z
z
Step-Up DC/DC converter with on-chip synchronous MOSFETs.(CH1)
Step-Down DC/DC converter with on-chip synchronous MOSFETs.(CH2)
Main synchronous DC/DC controller can be configured as either a Step-Up or
Step-Down converter.(CH3)
z
z
z
Selectable DC/DC controller for boost/flyback/buck/inverting converters.(CH4)
White LED driver with open LED protection or boost controller.(CH5)
Boost/flyback controller.(CH6)
Step-Up DC/DC Converter (CH1)
The step-up DC/DC converter typically is used to generate a 5V or the highest of the
DSC power system requirement from a 1.5V to 4.2V battery input and self-power the
AT1396. The efficiency is up to 95% with an internal MOSFET and external
synchronous rectifier.
Step-Down DC/DC Converter (CH2)
The step-down DC/DC is optimized for generating DSP core voltage (down to 0.8V)
at high efficiency. It runs from the voltage at PVCC2. This pin can be connected
directly to the battery if sufficient headroom exists to avoid dropout. It can be
powered from the output of another converter (CH1 or CH3) for boost-buck
operation.
The CH2 also features an open-drain /SDOK output that goes low when the CH2 is in
regulation. /SDOK may be used to drive an external P-MOSFET that gates 3.3V
power to the DSP after the core voltage is in regulation (Figure 1). The R1,R2 and C1
is for MOSFET soft-start function to avoid the more inrush current .
Step-Up or Step-Down DC/DC Converter (CH3)
The CH3 can be as a step-up (AT1396B/D) or step-down (AT1396A/C) voltage mode
PWM converter. An external MOSFET and synchronous rectifier allow conversion
efficiencies as high as 93%. Step-down operation can be direct from Li-Ion cell if the
minimum input voltage exceeds the desired output by approximately 200mV. When
7F, No.9, Park Avenue II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
4/2/2007 REV:1.1
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
17
GMT [ GLOBAL MIXED-MODE TECHNOLOGY INC ]
