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AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC Features
* Low start-up power supply voltage :1.4V(CH4) * Wide supply voltage range from 1.8V to 7V (CH1~4) * High speed operation is possible: Maximum 1 MHz * Supports for down and up/down Zeta conversion (CH1) * Supports for up, flyback and up/down SEPIC conversion (CH2,3,4) * Totem-pole type output for MOSFET * Built-in On/Off function * Built-in Short-Circuit Protection
General Description
The AT1382B is a 4-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, and up/down conversion (using a step-up/stepdown Zeta(CH1) and SEPIC(CH2,3,4) system with free input and output settings). Four channels can be built in the LQFP48 package, each channel be controlled, and soft-start. The AT1382B include one comparator to generate low-battery warning outputs. It also contains a gain block that can be used with an external P-channel MOSFET to make a low-dropout linear regulator.
Applications
* Digital Cameras * CCD Imaging Devices * Camcorders
Pin Assignment
Ordering Information
Part number AT1382BF Package LQFP48 Marking AT1382BF
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
AT1382B
Preliminary Product Information 4-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 DTC4 FB4 IN4 CS4 CTL4 DTC3 FB3 IN3 CS3 CTL3 CSCP VREF GND GND VBG VCC VCC POR RT CT VB CTL ENLD CT2 CTL2 CS2 IN2 FB2 DTC2 CTL1 CS1 IN1 FB1 DTC1 LBI LBO AI AO OUT1_1 OUT1_2 OUT2_1 OUT2_2 N.C. PVCC N.C. PGND OUT3 OUT4
I/O
I O I I I O I I O P P TEST P P TEST O I I TEST I I O I I I O I I O I O O O O O P P O O
Function
CH4 Dead Time Control CH4 Error Amplifier Output CH4 Error Amplifier Inverted Input CH4 Soft Start Setting Capacitor CH4 ON/OFF Control CH3 Dead Time Control CH3 Error Amplifier Output CH3 Error Amplifier Inverted Input CH3 Soft Start Setting Capacitor CH3 ON/OFF Control Timer Latch Short-Circuit Detection Capacitor Input Reference 0.9V Output Ground Ground Reference Test Pin Power Supply Power Supply Pre-OSC Change to Main-OSC Indicator Oscillation Frequency Setting Resistor Oscillation Frequency Setting Capacitor Reference 1.8V Output Power Supply Control Gain Block Enable Input Triangular wave OSC Inverted output Test Pin CH2 ON/OFF Control CH2 Soft Start Setting Capacitor CH2 Error Amplifier Inverted Input CH2 Error Amplifier Output CH2 Dead Time Control CH1 ON/OFF Control CH1 Soft Start Setting Capacitor CH1 Error Amplifier Inverted Input CH1 Error Amplifier Output CH1 Dead Time Control Low Battery Detected Input Low Battery Indicator LDO Regulated Input LDO Drive Output 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
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
AT1382B
Preliminary Product Information 4-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
AT1382B
Preliminary Product Information 4-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 8 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 Reference voltage output current VB pin output current Input voltage Control input voltage Output current Oscillator Timing capacitor Timing resistor Soft start capacitor Short detection capacitor VB pin capacitor Operating ambient temperature
Symbol
Vcc Vcc IOR IB VIN VCTL Io fOSC CT RT Cs CCS4 CSCP CVB Ta CH4 CH4
Condition Min
1.4 1.5 1.8 -1 -0.5 0 0 -1 100 47 8.2 ------0.082 -30 CH4 CH1 to CH3 VREF pin VB pin IN1 to IN4 pins CTL pin OUT pin (CH1 to CH3) OUT pin (CH4) ---CH1 to CH3
Unit Typ
-5.0 5.0 ----2 2 500 100 18 0.027 0.47 0.1 0.1 25
Max
7 7 7 0 0 Vcc-1.8 7 15 15 1000 560 100 1.0 1.0 1.0 -85 V V V mA mA V V mA mA kHz pF k 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
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
Electrical Characteristics
(Ta=25, VCC=PVCC=5V)
Parameter
Reference voltage block [REF] Reference voltage Output voltage temperature stability Input stability Load stability Shout circuit output current
Symbol
VREF
Condition
Measure result Unit Min. Typ. Max.
0.88 -10 -10 -20 0.90 0.5 -5 0.92 10 10 -1 V % mV mV mA
VREF Ta = -30 to 85 /VREF Line Load IOSC VTH VH VRST VTH2 VCC=1.8V to 7V VREF=0mA to -1mA VREF=0.7V
Under voltage lockout block [U.V.L.O] Threshold voltage(CH1~CH3) Hysteresis width(CH1~CH3) Reset voltage(CH1~CH3) CH4 Pre-OSC change to MainOSC threshold Soft start block [CS] Charge current Short circuit detection block [SCP] Threshold voltage Input source current VTH ICSCP 0.65 -1.5 0.70 -1.0 0.75 -0.7 V A ICS -6.0 -5.0 -4.0 A 1.5 1.6 1.6 0.2 1.7 1.7 1.7 1.8 V V V V
Triangular wave oscillator block [OSC] Oscillator frequency Frequency stability for voltage Frequency stability for temperature fOSC f /fdv f /fdt CT=100pF, RT=20k VCC=1.8V to 7V Ta=-30 to 85 400 500 1 1 600 10 kHz % %
Error amplifier block [Error Amp](CH1~CH4) Threshold voltage VT temperature stability Input bias current Voltage gain VTH FB=0.9V 0.69 -320 0.70 0.5 -80 100 0.71 V % nA dB
VT/VT Ta = -30 to 85 IB AV IN=0V DC
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
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
Frequency bandwidth Output voltage Output source current Output sink current BW VOH VOL ISOURCE FB=0.5V ISINK FB=0.5V AV=0dB 1.3 70 10 1.4 50 -4.0 140 200 -1.0 MHz V mV mA A
Short detect comparator [SCP Comp] Threshold voltage Input bias current PWM Comp. [PWM Comp] Threshold voltage(CH4) VT0 VTmax VT0 VTmax IDTC Duty = 0 % Duty = 100 % Duty = 0 % Duty = 100 % DTC=0.4V 0.25 0.20 -1.0 65 0.3 0.75 0.25 0.65 -0.3 -130 100 18 16 0.80 0.70 -80 30 25 A V V VTH IB CH1 to CH4 IN=0V 0.8 -320 0.9 -80 1.0 V nA
Threshold voltage(CH1~3) Input current Output block (CH1,2) [Pin 40,42] Output source current Output sink current Output ON resistor
ISOURCE Duty95%, OUT=0V ISINK ROH ROL Duty5%, OUT=5V OUT = -15mA OUT = 15mA
mA mA
Output block (CH1 to CH3) [Pin 39,41,47] Output source current Output sink current Output ON resistor Output block (CH4) [Pin 48] Output source current Output sink current Output ON resistor Control block [CTL] CTL input voltage CTL1 to CTL4 input voltage VIH VIL VIH Active mode Standby mode Active mode 1.3 0 1.3 7 0.8 7 V V V ISOURCE OUT=1/2PVCC ISINK ROH ROL OUT=1/2PVCV OUT = -15mA OUT = 15mA 150 -260 260 9 9 -160 15 15 mA mA ISOURCE Duty95%, OUT=0V ISINK ROH ROL Duty5%, OUT=5V OUT = -15mA OUT = 15mA 65 -130 100 18 16 -80 30 25 mA mA
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
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
VIL Input current Analog gain block [AO,AI] AI feedback regulation voltage AI input common-mode range AI input current AI to AO voltage gain AO output sink current AO output source current ENLD enable ENLD disable LBI detect threshold Detect Hysteresis LBO output voltage low LBO output high leakage General Standby current CTL=0V CTL=0V Icss(o) CTL1=CTL2=CTL3=CT L4="H" CTL=CTL1=CTL2=CTL Icc 3=CTL4=ENLD="H" Icss 3 10 10 6 A A mA Isink=1mA VLBO=5V VIH VIL VAI=1V, VAO=2V VAI=1.5V, VAO=2V Active mode Standby mode VAI=1.32V VAO=VOUT-1.22V 1.20 -0.1 70 0.5 0.5 1.2 0 1.20 -50 0.01 1.22 100 2.5 2.5 1.22 1.24 1.3 100 140 7 0.8 1.24 +50 0.4 1 V V nA V/V mA mA V V V mV V A ICTL Standby mode CTL = 5V 0 5 0.8 20 V A
Low battery detect block [LBI, LBO]
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
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
Typical Application
For 4 pcs AA Battery 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
AT1382B
Preliminary Product Information 4-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
AT1382B
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 AT1382B 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 pullup resistor. *Analog gain block The AT1382B 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 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 10
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
2.
Channel control function
The channels are turned on and turned off depending on the voltage levels at the CTL, CTL1, CTL2, CTL3 and CTL4. Described as follow.
CTL L
Voltage level at CTL pin CLT1 CLT2 CLT3 X X X L L H L H H L
H L
L H H H H L
CLT4 X L H L H L H L H L H L H L H L H
Channel on / off state CH1 CH2 CH3 OFF (Standby state) OFF OFF ON OFF ON ON OFF OFF ON ON ON ON OFF OFF
CH4 OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON
XUndefined
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 any channel output voltage falls below the short-circuit detection level, there is a constant current bias charging the external capacitor CSCP which connected to the CSCP pin until the capacitor voltage level reaches about 0.7V then turn off the output transistor and disable the IC. It could reset the actuated protection by restart the power source. *Under-voltage lockout protection The under-voltage lockout protection is to disable the IC while the supply voltage transient state 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 sets the dead time to 100% while holding the CSCP pin at the "L" level. The circuit restores the output transistor to normal when the power source voltage reaches the threshold voltage of the under-voltage lockout protection 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 11
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
4.
Soft Start Operation
When the CTL , CTL1, CTL2, CTL3 and CTL4 terminals are driven high level at the same time. The driving scheme is described as follow diagram. The capacitor connected to the CS1,CS2,CS3 and CS4 terminal starts charging and provides a soft start by comparing the CH1 to CH4 output 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 12
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
*When the CTL terminal is switch on, then each of the terminals CTL1, CTL2, CTL3, and CTL4 can be switched on or off independently. Any of the CTL1, CTL2, CTL3 and CTL4 terminals are driven 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 13
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
5.
Soft start setting
The soft start operation is determined by the capacitor connected to the CS1~CS4 terminal. Consider the input voltage and load current to design the soft start time. The soft start time until the DC/DC converter output voltage reaches 95%. It can calculate the soft start time Ts (s). Ts (s) = 0.084 * CS (F)
VCS = 0.7 x (1 - e
-(
Ts ) R xCs
)
R=
33.6 x 117.6 K 33.6 + 117.6
The soft start function of CH1 to CH4 are the same. It could be disabled soft start function by floating CS pin.
6.
Setting the output 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 14
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC 7. Setting time constant for Time-latch Short-circuit protection
The SCP comparator detects each channel output voltage while the power converter work at normal condition. Q1 is turn on, and the voltage level of CSCP pin is held at low level. If the load of one channel rapidly due to a short of the load, causing the output voltage to drop, the SCP comparator output on that channel goes to "H" level. The transistor Q1 to be turned off and the external capacitor CSCP to be charged at 1.0A. The time period of short circuit protection as show below equation. tPE(s): Short detection time
tPE (s) = 0.7 * CSCP (F) When the CSCP is charged to the 0.7V, the timer-latch is set and output is turn off (dead time is set to 100 ). At this point, the timer-latch is closed and the CSCP terminal is held at "L" level. 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 15
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC
8.
Setting the triangular oscillator frequency
The triangular oscillator frequency is determined by the timing capacitor (CT) connected to the CT terminal, and the timing resistor (RT) connected to the RT terminal.
f OSC ( kHz ) =
1000000 CT ( PF ) x RT ( k)
9.
Setting the DEAD time
When using step up or SEPIC 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. To set it, set the voltage at the DTC terminal by applying a resistive voltage divider to the VREF as shown below. When the voltage at the DTC pin is higher than the triangular wave voltage (CT), the output transistor is turned on. The maximum duty calculation formula assuming that triangular wave amplitude = V1(CH4=0.45,CH1~3=0.4) and triangular wave minimum voltage = Vx (CH4=0.3,CH1~3=0.25).
DUTY (ON ) max =
Vd - Vx x 100 V 1
If don't setting maximum duty, connect DTC terminal directly to the VREF terminal.
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
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC 10. Setting low battery detector threshold voltage
The low battery detected threshold voltage is determined by the external resistor connected to the LBI terminal. If Vin (battery voltage) under setting threshold voltage, low battery detect output terminal (LBO) is hold at "L" level. The driving scheme is described as follow diagram.
11. Decrease the Output Overshoot
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
AT1382B
Preliminary Product Information 4-Channel DC-DC Converter for DSC Typical Characteristics
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
AT1382B
Preliminary Product Information 4-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 19
AT1382B
Preliminary Product Information 4-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 20
AT1382B
Preliminary Product Information 4-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 21

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