AT1382B Preliminary Product Information 4-Channel DC-DC Converter for DSC Features General Description • 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 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. Applications 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. • 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: [email protected] 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: [email protected] 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: [email protected] 3 AT1382B Preliminary Product Information 4-Channel DC-DC Converter for DSC Absolute Maximum Ratings Parameter Symbol Condition Vcc -- Power supply voltage Rating Min Max Unit -- 8 V Output current Io Output pin -- 20 mA Output peak current Io Output pin, Duty≦5% -- 200 mA Power dissipation PD 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 Unit Min Typ Max Startup power supply voltage Vcc CH4 1.4 -- 7 V Power supply voltage Vcc CH4 CH1 to CH3 1.5 1.8 5.0 5.0 7 7 V V Reference voltage output current IOR VREF pin -1 -- 0 mA VB pin output current IB VB pin -0.5 -- 0 mA Input voltage VIN IN1 to IN4 pins 0 -- Vcc-1.8 V Control input voltage VCTL CTL pin 0 -- 7 V OUT pin (CH1 to CH3) -- 2 15 mA OUT pin (CH4) 1 2 15 mA Output current Io Oscillator fOSC -- 100 500 1000 kHz Timing capacitor CT -- 47 100 560 pF Timing resistor RT -- 8.2 18 100 kΩ Cs CH1 to CH3 -- 0.027 1.0 μF CH4 -- 0.47 1.0 μF Soft start capacitor CCS4 Short detection capacitor CSCP -- -- 0.1 1.0 μF VB pin capacitor CVB -- 0.082 0.1 -- μF Operating ambient temperature Ta -- -30 25 85 ℃ 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: [email protected] 4 AT1382B Preliminary Product Information 4-Channel DC-DC Converter for DSC Electrical Characteristics (Ta=25℃, VCC=PVCC=5V) Parameter Symbol Condition Measure result Unit Min. Typ. Max. Reference voltage block [REF] Reference voltage Output voltage temperature stability VREF △VREF Ta = -30℃ to 85℃ /VREF 0.88 0.90 0.92 V - 0.5 - % 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 IOSC VREF=0.7V -20 -5 -1 mA Under voltage lockout block [U.V.L.O] Threshold voltage(CH1~CH3) VTH 1.5 1.6 1.7 V Hysteresis width(CH1~CH3) VH - 0.2 - V Reset voltage(CH1~CH3) VRST 1.6 1.7 1.8 V CH4 Pre-OSC change to MainOSC threshold VTH2 - 1.7 - V ICS -6.0 -5.0 -4.0 μA Threshold voltage VTH 0.65 0.70 0.75 V Input source current ICSCP -1.5 -1.0 -0.7 μA 400 500 600 kHz Soft start block [CS] Charge current Short circuit detection block [SCP] Triangular wave oscillator block [OSC] Oscillator frequency fOSC CT=100pF, RT=20kΩ Frequency stability for voltage △f /fdv VCC=1.8V to 7V - 1 10 % Frequency stability for temperature △f /fdt Ta=-30℃ to 85℃ - 1 - % FB=0.9V 0.69 0.70 0.71 V △VT/VT Ta = -30℃ to 85℃ - 0.5 - % -320 -80 - nA - 100 - dB Error amplifier block [Error Amp](CH1~CH4) Threshold voltage VT temperature stability VTH Input bias current IB IN=0V Voltage gain AV 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: [email protected] 5 AT1382B Preliminary Product Information 4-Channel DC-DC Converter for DSC Frequency bandwidth Output voltage Output source current Output sink current BW AV=0dB - 10 - MHz VOH 1.3 1.4 - V VOL - 50 200 mV - -4.0 -1.0 mA FB=0.5V 70 140 - μA CH1 to CH4 0.8 0.9 1.0 V IN=0V -320 -80 - nA Duty = 0 % 0.25 0.3 - V - 0.75 0.80 V 0.20 0.25 - - 0.65 0.70 -1.0 -0.3 - μA - -130 -80 mA 65 100 - mA ISOURCE FB=0.5V ISINK Short detect comparator [SCP Comp] Threshold voltage VTH Input bias current IB PWM Comp. [PWM Comp] Threshold voltage(CH4) Threshold voltage(CH1~3) Input current VT0 VTmax VT0 Duty = 100 % Duty = 0 % VTmax Duty = 100 % IDTC DTC=0.4V Output block (CH1,2) [Pin 40,42] Output source current Output sink current Output ON resistor ISOURCE Duty≧95%, OUT=0V ISINK Duty≦5%, OUT=5V ROH OUT = -15mA - 18 30 Ω ROL OUT = 15mA - 16 25 Ω - -130 -80 mA 65 100 - mA Output block (CH1 to CH3) [Pin 39,41,47] Output source current Output sink current Output ON resistor ISOURCE Duty≧95%, OUT=0V ISINK Duty≦5%, OUT=5V ROH OUT = -15mA - 18 30 Ω ROL OUT = 15mA - 16 25 Ω - -260 -160 mA 150 260 - mA Output block (CH4) [Pin 48] Output source current Output sink current Output ON resistor ISOURCE OUT=1/2PVCC ISINK OUT=1/2PVCV ROH OUT = -15mA - 9 15 Ω ROL OUT = 15mA - 9 15 Ω VIH Active mode 1.3 - 7 V VIL Standby mode 0 - 0.8 V VIH Active mode 1.3 - 7 V Control block [CTL] CTL input voltage CTL1 to CTL4 input 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: [email protected] 6 AT1382B Preliminary Product Information 4-Channel DC-DC Converter for DSC Input current VIL Standby mode 0 - 0.8 V ICTL CTL = 5V - 5 20 μA 1.20 1.22 1.24 V -0.1 - 1.3 V - - 100 nA 70 100 140 V/V Analog gain block [AO,AI] AI feedback regulation voltage VAO=VOUT-1.22V AI input common-mode range AI input current VAI=1.32V AI to AO voltage gain AO output sink current VAI=1V, VAO=2V 0.5 2.5 - mA AO output source current VAI=1.5V, VAO=2V 0.5 2.5 - mA ENLD enable VIH Active mode 1.2 - 7 V ENLD disable VIL Standby mode 0 - 0.8 V LBI detect threshold 1.20 1.22 1.24 V Detect Hysteresis -50 +50 mV Low battery detect block [LBI, LBO] LBO output voltage low Isink=1mA - - 0.4 V LBO output high leakage VLBO=5V - 0.01 1 μA - - 10 μA - - 10 μA - 3 6 mA General Icss Standby current Power supply current CTL=0V CTL=0V Icss(o) CTL1=CTL2=CTL3=CT L4="H" CTL=CTL1=CTL2=CTL Icc 3=CTL4=ENLD="H" 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: [email protected] 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: [email protected] 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: [email protected] 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~1MΩ 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: [email protected] 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 L H H H L L H H L H H 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 OFF ON ON OFF OFF ON ON OFF ON ON CH4 OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON X：Undefined 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: [email protected] 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: [email protected] 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: [email protected] 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 (μF) VCS = 0.7 × (1 − e −( Ts ) R ×Cs ) R= 33.6 × 117.6 KΩ 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: [email protected] 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 1.0μA. The time period of short circuit protection as show below equation. tPE(s): Short detection time tPE (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. 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: [email protected] 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 ) = 9. 1000000 CT ( PF ) × RT ( kΩ) 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 × 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: [email protected] 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: [email protected] 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: [email protected] 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: [email protected] 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: [email protected] 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: [email protected] 21