AT1382A | DigiCamel IC Datasheet

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AT1382A AIMTRON | Alldatasheet

Document overview

Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
PDF pages: 25

Technical content

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 up, flyback and up/down SEPIC conversion (CH1~4)
Totem-pole type output for MOSFET
Built-in On/Off function
Built-in Short-Circuit Protection.

Applications

Digital Cameras
CCD Imaging Devices
Camcorders General Description The AT1382A 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/step- down SEPIC system with free input and output settings). Four channels can be built in the LQFP48 package, each channel be controlled, and soft-start. The AT1382A 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. Pin Assignment

Ordering Information

Part number Package Marking AT1382AF LQFP48 AT1382AF AT1382AF_PBF LQFP48, PB-Free AT1382AF,date code with one bottom line AT1382AF_GRE LQFP48,Green AT1382AF,date co de with two bottom line Aimtron reserves the right without notice to change this circuitry and specifications.

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Pin Description Pin No. Pin name I/O Function

1 DTC4 I CH4 Dead Time Control

2 FB4 O CH4 Error Amplifier Output

3 IN4 I CH4 Error Amplifier Inverted Input

4 CS4 - CH4 Soft Start Setting Capacitor

5 CTL4 I CH4 ON/OFF Control

6 DTC3 I CH3 Dead Time Control

7 FB3 O CH3 Error Amplifier Output

8 IN3 I CH3 Error Amplifier Inverted Input

9 CS3 - CH3 Soft Start Setting Capacitor

10 CTL3 I CH3 ON/OFF Control

11 CSCP - Timer Latch Short-Circ uit Detection Capacitor Input

12 VREF O Reference 0.9V Output

13 GND P Ground

14 GND P Ground

15 VBG TEST Reference Test Pin

16 VCC P Power Supply

17 VCC P Power Supply

18 POR TEST Pre-OSC Change to Main-OSC Indicator

19 RT - Oscillation Frequency Setting Resistor

20 CT - Oscillation Frequency Setting Capacitor

21 VB O Reference 1.8V Output

22 CTL I Power Supply Control

23 ENLD I Gain Block Enable Input

24 CT2 TEST Triangular wave OSC Inverted output Test Pin

25 CTL2 I CH2 ON/OFF Control

26 CS2 - CH2 Soft Start Setting Capacitor

27 IN2 I CH2 Error Amplifier Inverted Input

28 FB2 O CH2 Error Amplifier Output

29 DTC2 I CH2 Dead Time Control

30 CTL1 I CH1 ON/OFF Control

31 CS1 - CH1 Soft Start Setting Capacitor

32 IN1 I CH1 Error Amplifier Inverted Input

33 FB1 O CH1 Error Amplifier Output

34 DTC1 I CH1 Dead Time Control

35 LBI I Low Battery Detected Input

36 LBO O Low Battery Indicator

37 AI I LDO Regulated Input

38 AO O LDO Drive Output

39 OUT1_1 O CH1 Main Side Output

40 OUT1_2 O CH1 Synchronous Rectifier Side Output

41 OUT2_1 O CH2 Main Side Output

42 OUT2_2 O CH2 Synchronous Rectifier Side Output

43 N.C. -

44 PVCC P Drive Output Block Power Supply

45 N.C. -

46 PGND P Drive Output Block Ground

47 OUT3 O CH3 Output

48 OUT4 O CH4 Output

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Block Diagram

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Absolute Maximum Ratings RatingParameter Symbol Condition Min Max Unit Power supply voltage Vcc -- -- 8 V Output current Io Output pin -- 20 mA Output peak current Io Output pin, Duty≦5% -- 200 mA Power dissipation P D Ta≦25℃ (LQFP-48P) -- 860 mW Operation temperature Topr -- -30 85 ℃ Storage temperature Tstg -- -55 125 ℃ *Semiconductor devices can be permanently damaged by application of stress in excess of absolute ratings. Do not exceed these ratings. Recommended Operating Conditions Value Parameter Symbol Condition Min T yp Max Unit Startup power supply voltage Vcc CH4 1.4 -- 7 V CH4 1.5 5.0 7 VPower supply voltage Vcc CH1 to CH3 1.8 5.0 7 V Reference voltage output current I OR VREF pin -1 -- 0 mA VB pin output current I B VB pin -0.5 -- 0 mA Input voltage V IN IN1 to IN4 pins 0 -- Vcc-1.8 V Control input voltage V CTL CTL pin 0 -- 7 V OUT pin (CH1 to CH3) -- 2 15 mAOutput current Io OUT pin (CH4) 1 2 15 mA Oscillator f OSC -- 100 500 1000 kHz Timing capacitor C T -- 47 100 560 pF Timing resistor R T -- 8.2 18 100 kΩ Cs CH1 to CH3 -- 0.027 1.0 μF Soft start capacitor CCS4 CH4 -- 0.47 1.0 μF Short detection capacitor C SCP -- -- 0.1 1.0 μF VB pin capacitor C VB -- 0.082 0.1 -- μF Operating ambient temperature Ta -- -30 25 85 ℃

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw

Electrical Characteristics

(Ta=25℃, VCC=PVCC=5V) Measure resultParameter Symbol Condition Min. T yp. Max. Unit Reference voltage block [REF] Reference voltage V REF 0.88 0.90 0.92 V Output voltage temperature stability △VREF /VREF Input stability Line VCC=1.8V to 7V -10 - 10 mV Load stability Load VREF=0mA to –1mA -10 - 10 mV Shout circuit output current I OSC VREF=0.7V -20 -5 -1 mA Under voltage lockout block [U.V .L.O] Threshold voltage(CH1~CH3) V TH 1.5 1.6 1.7 V Hysteresis width(CH1~CH3) V H -0 . 2-V Reset voltage(CH1~CH3) V RST 1.6 1.7 1.8 V CH4 Pre-OSC change to Main- OSC threshold VTH2 -1 . 7-V Soft start block [CS] Charge current I CS -6.0 -5.0 -4.0 μA Short circuit detection block [SCP] Threshold voltage V TH 0.65 0.70 0.75 V Input source current I CSCP -1.5 -1.0 -0.7 μA Triangular wave oscillator block [OSC] Oscillator frequency f OSC CT=100pF, RT=20kΩ 400 500 600 kHz Frequency stability for voltage △f /fdv VCC=1.8V to 7V - 1 10 % Frequency stability for temperature /fdt Ta=-30℃ to 85 ℃ -1- % Error amplifier block [Error Amp](CH1~CH4) Threshold voltage V TH FB=0.9V 0.69 0.70 0.71 V VT temperature stability △VT/VT Ta = -30℃ to 85 ℃ -0 . 5-% Input bias current I B IN=0V -320 -80 - nA V oltage gain A V DC - 100 - dB

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Frequency bandwidth BW A V=0dB - 10 - MHz VOH 1.3 1.4 - VOutput voltage VOL -5 0 2 0 0 m V Output source current I SOURCE FB=0.5V - -4.0 -1.0 mA Output sink current I SINK FB=0.5V 70 140 - μA Short detect comparator [SCP Comp] Threshold voltage VTH CH1 to CH4 0.8 0.9 1.0 V Input bias current I B IN=0V -320 -80 - nA PWM Comp. [PWM Comp] VT0 Duty = 0 % 0.25 0.3 - V Threshold voltage(CH4) VTmax Duty = 100 % - 0.75 0.80 V VT0 Duty = 0 % 0.20 0.25 - Threshold voltage(CH1~3) VTmax Duty = 100 % - 0.65 0.70 Input current I DTC DTC=0.4V -1.0 -0.3 - μA Output block (CH1,2) [Pin 40,42] Output source current I SOURCE Duty≧95%, OUT=0V - -130 -80 mA Output sink current I SINK Duty≦5%, OUT=5V 65 100 - mA ROH OUT = -15mA - 18 30 Ω Output ON resistor ROL OUT = 15mA - 16 25 Ω Output block (CH1 to CH3) [Pin 39,41,47] Output source current I SOURCE Duty≧95%, OUT=0V - -130 -80 mA Output sink current I SINK Duty≦5%, OUT=5V 65 100 - mA ROH OUT = -15mA - 18 30 Ω Output ON resistor ROL OUT = 15mA - 16 25 Ω Output block (CH4) [Pin 48] Output source current I SOURCE OUT=1/2PVCC - -260 -160 mA Output sink current I SINK OUT=1/2PVCV 150 260 - mA ROH OUT = -15mA - 9 15 Ω Output ON resistor ROL OUT = 15mA - 9 15 Ω Control block [CTL] VIH Active mode 1.3 - 7 V CTL input voltage VIL Standby mode 0 - 0.8 V CTL1 to CTL4 input voltage V IH Active mode 1.3 - 7 V

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw VIL Standby mode 0 - 0.8 V Input current I CTL CTL = 5V - 5 20 μA Analog gain block [AO,AI] AI feedback regulation voltage V AO=VOUT-1.22V 1.20 1.22 1.24 V AI input common-mode range -0.1 - 1.3 V AI input current V AI=1.32V - - 100 nA AI to AO voltage gain 70 100 140 V/V AO output sink current V AI=1V , VAO=2V 0.5 2.5 - mA AO output source current V AI=1.5V , VAO=2V 0.5 2.5 - mA ENLD enable V IH Active mode 1.2 - 7 V ENLD disable V IL Standby mode 0 - 0.8 V Low battery detect block [LBI, LBO] LBI detect threshold 1.20 1.22 1.24 V Detect Hysteresis -50 +50 mV LBO output voltage low Isink=1mA - - 0.4 V LBO output high leakage VLBO=5V -0 . 0 11 μA General Icss CTL=0V - - 10 μA Standby current Icss(o) CTL=0V CTL1=CTL2=CTL3=CT L4="H" -- 1 0 μA Power supply current Icc CTL=CTL1=CTL2=CTL 3=CTL4=ENLD="H" -36 m A

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Typical Application

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw B. Using AT1382A on Buck Cnverter

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Function Description 1. Power Converter Functions

Reference voltage block The reference voltage circuit generates a te mperature 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 (amp litude 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 arbitr ary 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.

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 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. V oltage level at CTL pin Channel on / off state CTL CLT1 CLT2 CLT3 CLT4 CH1 CH2 CH3 CH4 L X X X X OFF (Standby state) LO F FL H OFF ON LO F F L H H OFF ON ON LO F FL H OFF ON LO F F L H H H OFF ON ON ON LO F FL H OFF ON LO F F L H H OFF ON ON LO F FL H OFF ON LO F F H H H H H ON ON ON ON X：Undefined 3. Protective Functions

Short circuit protection and timer latch The short circuit detection comparator in each ch annel detects the output voltage level of power converter. When any channel output voltage falls be low the short-circuit detection level, there is a constant current bias chargi ng the external capacitor C SCP 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.

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 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 .

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw

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.

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 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 (μF) 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 )1(7.0 CsR Ts CS eV × −×= Ω+ ×= KR 6.1176.33 6.1176.33

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 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 leve l 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 channe l goes to "H" level. The transistor Q1 to be turned off and the external capacitor C SCP to be charged at 1.0μA. The time period of short circuit protection as show below equation. t PE(s): Short detection time t PE (s) = 0.7 * CSCP (μF) 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.

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 8. Setting the triangular oscillator frequency The triangular oscillator frequency is determined by the timing capacitor (C T) connected to the CT terminal, and the timing resistor (RT) connected to the RT terminal. 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 If don't setting maximum duty, connect DTC terminal directly to the VREF terminal. ﹪1001max)( ×∆ −= V VxVdONDUTY )()( 1000000)( Ω×= kRPFCkHzf TT OSC

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 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

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Synchronous Rectification Reference Data

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw *if VCC=PVCC=3.3V , the efficiency will decrease about 0.2~05 % because of the N- MOSFET AO3400 Rds(on) increase.

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw Typical Characteristics

Preliminary Product Information 4-Channel DC-DC Converter for DSC Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw

Product Information

AT1382A specifications and overview.

Summary

4-Channel DC-DC Converter for DSC

Description

4-Channel DC-DC Converter for DSC

Source title AT1382A Datasheet(PDF) - Aimtron Technology

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