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AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC Features
* Low start-up power supply voltage :1.4V(CH5) * Wide supply voltage range from 2.5V to 7V (CH1~5) * High speed operation is possible: Maximum 1 MHz * Supports for up,down, flyback and up/down SEPIC conversion * Supports for inverting conversion (CH4) * Synchronized rectification on CH1,CH2 * Selectable P-Ch/N-CH MOSFETdriver * Built-in On/Off function * Built-in Short-Circuit Protection.
General Description
The AT1395 is a 5-channel PWM DC/DC control IC for low voltage applications with a soft start function and short circuit detection function. This IC is ideal for up conversion, down conversion, inverting conversion (CH4 only) and up/down conversion (using a step-up/step-down SEPIC or Zeta system with free input and output settings). 5 channels can be built in the LQFP48 package, each channel be controlled, and soft-start. The AT1395 include one comparator to generate low-battery warning outputs. It also contains two high efficiency topology by using synchronous rectification PWM (It can be disable by floating OUT1_2,OUT2_2.)
Applications
* Digital Cameras * CCD Imaging Devices * Camcorders
Pin Assignment
Ordering Information
Part number AT1395F Package LQFP48 Marking AT1395F
Aimtron reserves the right without notice to change this circuitry and specifications.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 1
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC Pin Description Pin No. Pin name
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 SS5 FB5 IN5E SEL4 DTC4 SS4 FB4 IN4N IN4P SEL3 DTC3 SS3 FB3 IN3E CTL5 CTL4 CTL3 VREG VREFO AGND VCC VBC CT CTL CSCP CTL2 CTL1 IN2E FB2 SS2 DTC2 SEL2 IN1E FB1 SS1 DTC1 SEL1 LBI LBO OUT1_1 OUT1_2 OUT2_1 OUT2_2 PVCC PGND OUT3 OUT4 OUT5
I/O
I I I I I I I I I I I I I I I I I O P P I I I I I I I I I I I I I I O O O O O P P O O O
Function
CH5 Soft Start Setting Capacitor CH5 Error Amplifier Output CH5 Error Amplifier Inverted Input CH4 Output Driver P-ch/N-ch Control CH4 Dead Time Control CH4 Soft Start Setting Capacitor CH4 Error Amplifier Output CH4 Error Amplifier Negative Input CH4 Error Amplifier Positive Input CH3 Output Driver P-ch/N-ch Control CH3 Dead Time Control CH3 Soft Start Setting Capacitor CH3 Error Amplifier Output CH3 Error Amplifier Inverted Input CH5 ON/OFF Control Input CH4 ON/OFF Control Input CH3 ON/OFF Control Input 2.2V Regulator Output Reference bypass Input Power Ground Power Supply Bias bypass Input Oscillation Frequency Setting Capacitor Power Control Input Timer Latch Short-Circuit Detection Capacitor Input CH2 ON/OFF Control Input CH1 ON/OFF Control Input CH2 Error Amplifier Inverted Input CH2 Error Amplifier Output CH2 Soft Start Setting Capacitor CH2 Dead Time Control CH2 Output Driver P-ch/N-ch Control CH1 Error Amplifier Inverted Input CH1 Error Amplifier Output CH1 Soft Start Setting Capacitor CH1 Dead Time Control CH1 Output Driver P-ch/N-ch Control Low Battery Detector Input Low Battery Indicator CH1 Main Side Output CH1 Synchronous Rectifier Side Output CH2 Main Side Output CH2 Synchronous Rectifier Side Output Drive Output Block Power Supply Drive Output Block Ground CH3 Output CH4 Output CH5 Output
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 2
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC Block Diagram
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 3
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Absolute Maximum Ratings Parameter
Power supply voltage Output current Output peak current Power dissipation Operation temperature Storage temperature
exceed these ratings.
Symbol
Vcc Io Io PD Topr Tstg
Condition
-Output pin Output pin, Duty5% Ta25 (LQFP-48P) ---
Rating Min Max
-----30 -55 7 20 200 860 85 125
Unit
V mA mA mW
*Semiconductor devices can be permanently damaged by application of stress in excess of absolute ratings. Do not
Recommended Operating Conditions Value Parameter
Startup power supply voltage Power supply voltage Regulator voltage output current Input voltage Control input voltage Output current Oscillator Timing capacitor Soft start capacitor Short detection capacitor VREG pin capacitor Operating ambient temperature
Symbol
Vcc1 Vcc2 IOR VIN VCTL Io fOSC CT Cs CSS6 CCSCP CVREG TA CH5 CH5
Condition Min
1.4 2.5 -10 0 0 -1 100 47 ------0.082 -30 CH1 to CH4 VREG pin IN1E to IN5E pins CTL pin OUT pin (CH1 to CH4) OUT pin (CH5) --CH1 to CH4
Unit Typ
-3.3 ---2 2 500 100 0.1 0.1 0.1 0.1 25
Max
6.5 6.5 0 Vcc-1.8 7 15 15 1000 560 1.0 1.0 1.0 -85 V V mA V V mA mA kHz pF F F F F
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 4
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC Electrical Characteristics
(TA=25, VCC=PVCC=5V)
Parameter
Reference voltage block [REF] Regulator voltage Output voltage temperature stability Input stability Load stability Threshold voltage(CH1~CH4) Hysteresis width(CH1~CH4) Reset voltage(CH1~CH4) CH5 Pre-OSC change to MainOSC threshold Pre-OSC frequency(CH6) Soft start block [CS] Charge current
Symbol
VREG
Condition
Measure result Unit Min. Typ. Max.
2.15 -10 -10 2.0 0.05 320 2.2 0.5 2.2 0.1 1.8 400 2.25 10 10 2.4 0.3 2.5 450 V % mV mV V V V V KHz
VREG TA = -30 to 85 /VREG Line Load VTH VH VRST VTH fPre-OSC VCC=2.5V to 7V VREG=0mA to -1mA
Under voltage lockout block [U.V.L.O]
ICS VTH VSTB VI ICSCP
-3.0 0.65 -1.4
-2.5 0.70 50 50 -1.0
-2.0 0.75 100 100 -0.6
A
Short circuit detection block [SCP] Threshold voltage Input standby voltage Input latch voltage Input source current V mV mV A
Triangular wave oscillator block [OSC] Oscillator frequency Frequency stability for voltage Frequency stability for temperature CH5 Maximum Duty fOSC f /fdv f /fdt DUTY CT=75pF VCC=2.5V to 7V TA=-30 to 85 450 500 1 1 550 10 20 kHz % %
80
90
-
%
Error amplifier block [Error Amp](CH1~CH5) Threshold voltage VREF FB=1.22V 1.20 1.22 1.24 V
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 5
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
VT temperature stability Input bias current Voltage gain Frequency bandwidth Output voltage Output source current Output sink current VT/VT TA = -30 to 85 IB AV BW VOH VOL ISOURCE FB=0.5V ISINK FB=0.5V IN=0V DC AV=0dB -320 1.3 70 0.5 -80 100 10 1.5 20 -2.0 120 200 -1.0 % nA dB MHz V mV mA A
Short detect comparator [SCP Comp] Threshold voltage Threshold voltage Input bias current PWM Comp. [PWM Comp] Threshold voltage(CH1~6) Input current Output source current Output sink current Output ON resistor Output block (CH1,2 ) [Pin 41,43] Output source current Output sink current Output ON resistor Output block (CH5) [Pin 48] Output source current Output sink current Output ON resistor Control block [CTL] CTL input voltage VIH VIL Active mode Standby mode 1.3 0 7 0.8 V V ISOURCE Duty=90%, OUT=VCC/2 ISINK ROH ROL Duty5%, OUT=VCC/2 OUT = -15mA OUT = 15mA 150 -260 260 9 9 -160 15 15 mA mA ISOURCE OUT=VCC/2 ISINK ROH ROL OUT=VCC/2 OUT = -15mA OUT = 15mA 65 -130 100 18 16 -80 30 25 mA mA VT0 VTmax IDTC Duty = 0 % Duty = 100 % DTC=0.5V 0.25 -1.0 65 0.3 0.80 -0.3 -130 100 18 16 0.85 -80 30 25 V V A mA mA VTH VTH IB CH1 to CH4 CH5 IN=0V 0.9 0.8 -320 1.0 0.9 -80 1.1 1.0 V V nA
Output block (CH1 to CH4) [Pin 40,42,46,47] ISOURCE OUT=VCC/2 ISINK ROH ROL OUT=VCC/2 OUT = -15mA OUT = 15mA
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 6
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
CTL1 to CTL5 input voltage Input current SEL block [CTL] SEL1 to SEL4 input voltage VIH VIL N-CH Drive P-CH Drive VCC/2 0 1.20 -50 Isink=1mA VLBO=5V CTL=CTL1=CTL2=CTL 3=CTL4=CTL5=0V CTL=0V, Icss(o) CTL1=CTL2=CTL3=CT L4= CTL5="H" CTL=CTL1=CTL2=CTL Icc 3=CTL4=CTL5="H" Icss 0.01 1.22 7 0.8 1.24 +50 0.4 1 V V V mV V A VIH VIL ICTL Active mode Standby mode CTL = 5V 1.3 0 5 7 0.8 20 V V A
Low battery detect block [LBI, LBO] LBI detect threshold Detect Hysteresis LBO output voltage low LBO output high leakage General 1 200 3 10 250 7 A A mA
Standby current
Power supply current
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 7
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Application Circuit
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 8
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 9
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 10
AT1395
Preliminary Product Information 5-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=2.2V) from the power source, which is used as reference voltage for the IC's internal circuitry and supply load current above 10mA to external device. Triangular oscillator block The triangular wave oscillator is generated by timing capacitor(CT) to incorporate each other. The waveforms CT (amplitude of 0.3V to 0.8V), CT1 (amplitude 0.3V to 0.8V in phase with CT) and CT2 (amplitude 0.3V to 0.8V 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 system. CH4 Inverting amplifier block The inverting amplifier detects the DC/DC converter output voltage (negative) and outputs a control signal to the error amplifier. PWM comparator block The PWM comparator is a voltage-to-pulse width converter for controlling the duty cycle of DC/DC converter. Channels 1, 2 main sides, channel 3, 4, and 5: 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, 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.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 11
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC Output block The output block is the totem pole configuration, which could drive external MOSFET or transistor. It can be drive the external N-MOSFET by force the SEL to High, and it can be drive the external P-MOSFET by force the SEL to LOW.
2. Channel Control Function The channels are turned on and turned off depending on the voltage levels at the CTL, CTL12, CTL3, CTL4, CTL5, and CTL6. Described as follow. CTL CTL1 CTL2 CTL3 CTL4 CTL5 CH1 CH2 CH3 CH4 CH5 L X X X X X OFF H Z Z H Z Z OFF OFF ON OFF OFF
H Z Z Z Z ON OFF OFF OFF OFF
Z H Z Z Z OFF ON OFF OFF OFF
Z Z Z H Z OFF OFF OFF ON OFF
Z Z Z Z H OFF OFF OFF OFF ON
X : Don't care
Z: Low or Floating
3. Protective Functions Short circuit protection and timer latch The short circuit detection comparator in each channel detects the output voltage level of power converter. When the output voltage falls below the short detection level, there is a constant current bias charging the external capacitor CCSCP which connected to the CSCP pin until the capacitor voltage level reaches about 0.7V then disable the IC. It could reset the actuated protection by restart the power source or pull CTL from low to high.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 12
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Under-voltage lockout protection The under-voltage lockout protection is to disable the IC while the supply voltage transient or momentary decrease, which may cause the IC to malfunction. To prevent such malfunctions, the under-voltage lockout protection circuit detects a decrease in internal reference voltage with respect to the power supply voltage, turns off the output transistor, and holding the CSCP pin at the "L" level. Battery Low Detect Function The 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~1M pull-up resistor.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 13
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
4. Soft Start Operation After CTL ON, driving the CTL1, CTL2, CTL3, CTL4 and CTL5 to high level. The driving scheme is described as follow diagram.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 14
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Soft start setting (CH1~5) Consider the input voltage and load current to design the capacitor connected to the SS pin.
It can calculate the CH1~5 soft start time Ts(s).
Cx
V =I t
Ts( s ) = 0.2 x C ( F )
Note : It could be disabled soft start function by floating SS pin.
Determine the triangular Oscillator Frequency The triangular oscillator frequency is determined by the timing capacitor (CT). It is difficult to incorporate these non-linear characteristics into the equation. This difference is caused by characteristics, such as changes in the maximum voltage amplitude of the sawtooth waveform with the CT value and the circuit delay causing the maximum amplitude to become large in the case of a high oscillating frequency even for the same capacitor. In practical use, therefore, the user should read the CT values from the characteristic curve or should determine an approximate target value by using the equation.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 15
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Design the DC/DC Output Voltage CH1~5
Setting Time Period When Short Circuit Protection The CSCP comparator detects each channel output voltage while the power converter work at normal condition. At the same time, the voltage level of CSCP pin is held at low level. If the output load of these converters rapidly malfunction or short, causing the output voltage to drop, the CSCP comparator detects that to enable short circuit protection. The time period when short circuit protection show as follow equation. Short detection time (TPE(s))
TPE(s) = 0.7 * CCSCP (F) Note : It could be disabled short circuit protection function by connecting CSCP pin into the ground.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 16
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Setting the Dead Time Control Level When using Boost, SEPIC, Zeta or flyback DC/DC converter, it must prevent that output transistor works at full-ON state (ON duty = 100%). To prevent this situation, set the maximum duty of these channels. The dead time control circuit is implemented as below. When the voltage at the DTC pin is higher than the triangular wave voltage (CT, CT1, CT2), the output transistor is turned on. The maximum duty calculation formula assuming that triangular wave amplitude = 0.5V and triangular wave minimum voltage = 0.3V.
Duty MAX . = (
Vd - 0.3 ) x 100% 0.5
Note 1 : The circuit is suitable at CH1 to CH6. Note 2 : Shorting DTC and VREG to disable dead time control function.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 17
AT1395
Preliminary Product Information 5-Channel DC-DC Converter for DSC
Package Outline LQFP48
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 18

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