AT1395 | DigiCamel IC Datasheet

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AT1395 ETC | Alldatasheet

Document overview

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PDF pages: 18

Technical content

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.

Applications

Digital Cameras
CCD Imaging Devices
Camcorders 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 co mparator 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.) Pin Assignment

Ordering Information

Part number Package Marking AT1395F LQFP48 AT1395F Aimtron reserves the right without notice to change this circuitry and specifications.

Preliminary Product Information 5-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 SS5 I CH5 Soft Start Setting Capacitor

2 FB5 I CH5 Error Amplifier Output

3 IN5E I CH5 Error Amplifier Inverted Input

4 SEL4 I CH4 Output Driver P-ch/N-ch Control

5 DTC4 I CH4 Dead Time Control

6 SS4 I CH4 Soft Start Setting Capacitor

7 FB4 I CH4 Error Amplifier Output

8 IN4N I CH4 Error Amplifier Negative Input

9 IN4P I CH4 Error Amplifier Positive Input

10 SEL3 I CH3 Output Driver P-ch/N-ch Control

11 DTC3 I CH3 Dead Time Control

12 SS3 I CH3 Soft Start Setting Capacitor

13 FB3 I CH3 Error Amplifier Output

14 IN3E I CH3 Error Amplifier Inverted Input

15 CTL5 I CH5 ON/OFF Control Input

16 CTL4 I CH4 ON/OFF Control Input

17 CTL3 I CH3 ON/OFF Control Input

18 VREG O 2.2V Regulator Output

19 VREFO - Reference bypass Input

20 AGND P Power Ground

21 VCC P Power Supply

22 VBC - Bias bypass Input

23 CT - Oscillation Frequency Setting Capacitor

24 CTL I Power Control Input

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

26 CTL2 I CH2 ON/OFF Control Input

27 CTL1 I CH1 ON/OFF Control Input

28 IN2E I CH2 Error Amplifier Inverted Input

29 FB2 I CH2 Error Amplifier Output

30 SS2 I CH2 Soft Start Setting Capacitor

31 DTC2 I CH2 Dead Time Control

32 SEL2 I CH2 Output Driver P-ch/N-ch Control

33 IN1E I CH1 Error Amplifier Inverted Input

34 FB1 I CH1 Error Amplifier Output

35 SS1 I CH1 Soft Start Setting Capacitor

36 DTC1 I CH1 Dead Time Control

37 SEL1 I CH1 Output Driver P-ch/N-ch Control

38 LBI I Low Battery Detector Input

39 LBO O Low Battery Indicator

40 OUT1_1 O CH1 Main Side Output

41 OUT1_2 O CH1 Synchronous Rectifier Side Output

42 OUT2_1 O CH2 Main Side Output

43 OUT2_2 O CH2 Synchronous Rectifier Side Output

44 PVCC P Drive Output Block Power Supply

45 PGND P Drive Output Block Ground

46 OUT3 O CH3 Output

47 OUT4 O CH4 Output

48 OUT5 O CH5 Output

Preliminary Product Information 5-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 5-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 -- -- 7 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 Vcc1 CH5 1.4 -- 6.5 V Power supply voltage Vcc2 CH1 to CH4 2.5 3.3 6.5 V Regulator voltage output current I OR VREG pin -10 -- 0 mA Input voltage V IN IN1E to IN5E pins 0 -- Vcc-1.8 V Control input voltage V CTL CTL pin 0 -- 7 V OUT pin (CH1 to CH4) -- 2 15 mAOutput current Io OUT pin (CH5) 1 2 15 mA Oscillator f OSC -- 100 500 1000 kHz Timing capacitor C T -- 47 100 560 pF Cs CH1 to CH4 -- 0.1 1.0 μF Soft start capacitor CSS6 CH5 -- 0.1 1.0 μF Short detection capacitor C CSCP -- -- 0.1 1.0 μF VREG pin capacitor C VREG -- 0.082 0.1 -- μF Operating ambient temperature TA -- -30 25 85 ℃

Preliminary Product Information 5-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] Regulator voltage V REG 2.15 2.2 2.25 V Output voltage temperature stability △VREG /VREG Input stability Line VCC=2.5V to 7V -10 - 10 mV Load stability Load VREG=0mA to –1mA -10 - 10 mV Under voltage lockout block [U.V .L.O] Threshold voltage(CH1~CH4) V TH 2.0 2.2 2.4 V Hysteresis width(CH1~CH4) V H 0.05 0.1 0.3 V Reset voltage(CH1~CH4) V RST -- 2 . 5 V CH5 Pre-OSC change to Main- OSC threshold VTH -1 . 8-V Pre-OSC frequency(CH6) f Pre-OSC 320 400 450 KHz Soft start block [CS] Charge current I CS -3.0 -2.5 -2.0 μA Short circuit detection block [SCP] Threshold voltage V TH 0.65 0.70 0.75 V Input standby voltage V STB -5 0 1 0 0 m V Input latch voltage V I -5 0 1 0 0 m V Input source current I CSCP -1.4 -1.0 -0.6 μA Triangular wave oscillator block [OSC] Oscillator frequency f OSC CT=75pF 450 500 550 kHz Frequency stability for voltage △f /fdv VCC=2.5V to 7V - 1 10 % Frequency stability for temperature /fdt TA=-30℃ to 85 ℃ -1 2 0 % CH5 Maximum Duty DUTY 80 90 - % Error amplifier block [Error Amp](CH1~CH5) Threshold voltage V REF FB=1.22V 1.20 1.22 1.24 V

Preliminary Product Information 5-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 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 Frequency bandwidth BW A V=0dB - 10 - MHz VOH 1.3 1.5 - VOutput voltage VOL -2 0 2 0 0 m V Output source current I SOURCE FB=0.5V - -2.0 -1.0 mA Output sink current I SINK FB=0.5V 70 120 - μA Short detect comparator [SCP Comp] Threshold voltage VTH CH1 to CH4 0.9 1.0 1.1 V Threshold voltage VTH CH5 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(CH1~6) VTmax Duty = 100 % - 0.80 0.85 V Input current I DTC DTC=0.5V -1.0 -0.3 - μA Output block (CH1 to CH4) [Pin 40,42,46,47] Output source current I SOURCE OUT=VCC/2 - -130 -80 mA Output sink current I SINK OUT=VCC/2 65 100 - mA ROH OUT = -15mA - 18 30 Ω Output ON resistor ROL OUT = 15mA - 16 25 Ω Output block (CH1,2 ) [Pin 41,43] Output source current I SOURCE OUT=VCC/2 - -130 -80 mA Output sink current I SINK OUT=VCC/2 65 100 - mA ROH OUT = -15mA - 18 30 Ω Output ON resistor ROL OUT = 15mA - 16 25 Ω Output block (CH5) [Pin 48] Output source current I SOURCE Duty=90%, OUT=VCC/2 - -260 -160 mA Output sink current I SINK Duty≦5%, OUT=VCC/2 150 260 - 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

Preliminary Product Information 5-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 VIH Active mode 1.3 - 7 V CTL1 to CTL5 input voltage VIL Standby mode 0 - 0.8 V Input current I CTL CTL = 5V - 5 20 μA SEL block [CTL] VIH N-CH Drive VCC/2 - 7 V SEL1 to SEL4 input voltage VIL P-CH Drive 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=CTL1=CTL2=CTL 3=CTL4=CTL5=0V -1 1 0 μA Standby current Icss(o) CTL=0V , CTL1=CTL2=CTL3=CT L4= CTL5="H" -2 0 0 2 5 0 μA Power supply current Icc CTL=CTL1=CTL2=CTL 3=CTL4=CTL5="H" -37 m A

Preliminary Product Information 5-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 Application Circuit

Preliminary Product Information 5-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 5-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 genera tes 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 genera ted by timing capacitor(CT) to incorporate each other. The waveforms CT (amp litude 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 out put 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 erro r amplifier output voltage and DTC voltage still higher than the triangular wave voltage. Channels 1, 2 synchronous rectification si des : The comparator keeps the output transistor turn on while the error amplif ier output voltage still lower than the triangular wave voltage.

Preliminary Product Information 5-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 ＊ Output block The output block is the totem pole c onfiguration, which co uld 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 of f depending on the voltage levels at the CTL, CTL12, CTL3, CTL4, CTL5, and CTL6. Described as follow. CTL L H CTL1 X H Z Z Z Z CTL2 X Z H Z Z Z CTL3 X Z Z H Z Z CTL4 X Z Z Z H Z C T L 5 X ZZZZH CH1 ON OFF OFF OFF OFF CH2 OFF ON OFF OFF OFF CH3 OFF OFF ON OFF OFF CH4 OFF OFF OFF ON OFF CH5 OFF 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 curr ent bias charging the external capacitor CCSCP which connected to the CSCP pin unt il the capacitor vo ltage level reaches about 0.7V then disable the IC. It coul d reset the actuated protection by restart the power source or pull CTL from low to high.

Preliminary Product Information 5-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 ＊ Under-voltage lockout protection The under-voltage lockout protection is to disable the IC while the supply voltage transient or momentary decrease, whic h may cause the IC to malfunction. To prevent such malfunctions, the under-voltage lockout protection circuit detects a decrease in internal refere nce 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 ou tput LBO sinks up to 1mA if the LBI input is below its threshold voltage. Connect LBO to power source with a 100KΩ~1MΩ pull-up resistor.

Preliminary Product Information 5-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 ＊ After CTL ON, driving the CTL1, CTL2, CTL3, CTL4 and CTL5 to high level. The driving scheme is described as follow diagram.

Preliminary Product Information 5-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 ＊ Soft start setting (CH1~5) Consider the input voltage and load current to desi gn the capacitor connected to the SS pin. It can calculate the CH1~5 soft start time Ts(s). 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 (C T). It is difficult to incorporate these non-linear characteristics in to 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 us e, therefore, the user should read the CT values from the characteristic curve or shou ld determine an approximate target value by using the equation. It VC =∆ )(2.0)( FCsTs µ×=

Preliminary Product Information 5-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 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 (T PE(s)) T PE(s) = 0.7 * CCSCP (μF) Note : It could be disabled short circuit protection function by connecting CSCP pin into the ground.

Preliminary Product Information 5-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 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), th e output transistor is turned on. The maximum duty calculation formula assumi ng that triangular wave amplitude = 0.5V and triangular wave minimum voltage = 0.3V . Note 1 : The circuit is suitable at CH1 to CH6. Note 2 : Shorting DTC and VREG to disable dead time control function. %100)5.0 3.0(. ×−= VdDutyMAX

Preliminary Product Information 5-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 Package Outline LQFP48

Product Information

AT1395 specifications and overview.

Summary

5 CHANNEL DC-DC CONVERTER FOR DSC

Description

5 CHANNEL DC-DC CONVERTER FOR DSC

Source title AT1395 Datasheet(PDF) - List of Unclassifed Manufacturers

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