AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Features • 95% Efficient possible DC/DC Converter • Combine Step-Up and Step-Down for 90% Efficient Boost-Buck • Bulit-in LED Driver and Open LED Overvoltage Protection • Transformerless Inverting Controller for CCD Bias • 2 Channel Built-in MOSFET Current- Mode PWM and 4 Channel Extra PWM Controllers (CH-3 Synchronous Output) • Up to 1MHz Operating Frequency • Shutdown Current <1uA • Built-in Soft-Start Function • Built-in Short-Circuit Protection Function • QFN48 Package General Description The AT1396A/B/C/D provide a complete power supply solution for digital cameras. They improve performance, component count, and size compared to other multi-channel controllers in 2-cell AA, 1-cell Li-Ion, and dual-battery designs. On-chip MOSFETs provide up to 92~95% efficiency for critical power supplies, while additional channels operate with external FETs for optimum design flexibility. All channels DC/DC operate at one fixed frequency settable from 100KHz to 1MHz to optimize size, cost, and efficiency. Applications • DSC Power Supply Pin Assignment Ordering Information Part Number AT1396AN AT1396BN AT1396CN AT1396DN Package QFN48,Green QFN48,Green QFN48,Green QFN48,Green Marking AT1396AN AT1396BN AT1396CN AT1396DN 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-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] 2 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-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 SS1 CTL5 CTL6 LXU CTLU PGND1 PGND2 CTLD LXD CTL3 CTL4 SS2 /SDOK CSCP PVCC2 COMP2 FBD SS3 COMP3 FB3 SS4 COMP4 IN4 IP4 PVCC3 OUT3M OUT3S PGND3 OUT4 OUT5 OUT6 PVCC4 GND FB5H FB5 COMP5 VBG SS5 FB6 COMP6 CT VREG FBU COMP1 VCC PVCC1 SS6 SEL4 I/O I I I O I P P I O I I I O I P O I I O I I O I I P O O P O O O P P I I O O I I O O P I O P P I I Description CH1 Soft-Start Input CH5 Enable Input CH6 Enable Input Step-Up Converter Switching Node CH1 Enable and Chip Enable Input Power Ground Power Ground CH2 Enable Input Step-Down Converter Switching Node CH3 Enable Input CH4 Enable Input CH2 Soft-Start Input Open-Drain, Active Low, Power Good for Step-Down Short Circuit Protection Input Step-Down Converter Input Step-Down Converter Compensation Node Step-Down Converter Feedback Input CH3 Soft-Start Input CH3 Compensation Node CH3 Feedback Input CH4 Soft-Start Input CH4 Compensation Node CH4 Negative Feedback Input CH4 Positive Feedback Input CH3 Power CH3 Master Output Driver CH3 Slave Output Driver Power Ground CH4 Output Driver CH5 Output Driver CH6 Output Driver CH4 Power Power Ground CH5 Controller Voltage Feedback Input CH5 Controller Voltage Feedback/Current Feedback CH5 Compensation Node Reference Bypass CH5 Soft-Start Input CH6 Feedback input CH6 Compensation Node Oscillator Control Reference Output Step-Up Converter Input Step-Up Controller Compensation Node IC power Input Power Output of the Step-Up Converter CH6 Soft-Start Input Configures the CH4 as a Step-Up or Step-Down 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Absolute Maximum Ratings Item Symbol Ratings Units Storage temperature Operating temperature TSTG TOPR -55～＋150 -30～＋85 -0.3～＋5.5 ℃ ℃ V VLX/OUT -0.3V～+5.5 V -0.3V～+5.5 3.6 2.25 200 1000 2 V A A mA mW KV PVCC1,PVCC2,PVCC3,PVCC 4 input voltage LXU,LXD, OUT3M,OUT3S input voltage Other input Pin LXU Current LXD Current OUT3M,OUT3S Current Power consumption ESD Classification Pd Electrical Characteristics (PVCC1=PVCC2=PVCC3=PVCC4=VCC=3.6V, Ta=+250C) Values Parameter Symbol Condition Unit Min. Typ. Max. 1.2 - 5.5 V - 1 1.1 mA - 1.2 1.3 mA - 1 10 μA 2.275 2.30 2.325 V - 5 10 mV - - 5 mV CT=82pF - 500 - KHz ∆fOSC1 Ta=-20°C ~+85°C - 1 10 % GENERAL Input Voltage Range VCC Channel 1 DC/DC CH1,CH2 Switch- Off Input Current IVCC CH1,CH2, CH3(or 4,5,6) Switch- Off Input Current IVCC Shutdown Current IVCC No Switching, FBU=FBD=0.9V CTLU=CTLD=3.6V,other disable No Switching, FBU=FBD=FB3=0.9V CTLU=CTLD=CTL3=3.6V other disable All CTL disable REFERENCE Reference Output Voltage Reference Load Regulation VREG IREG =1mA ∆VREG1 1mA< IREG <10mA Reference Line Regulation ∆VREG2 2.5<VCC<5.5V OSC Frequency Frequency variation with Temperature fOSC 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Frequency variation with Input Voltage ∆fOSC2 VCC =2.5V~5.5V - 1 5 % - 2.45 - V ∆VCC1 - 100 - mV VCC - 2.45 - V 1.2 - 6.0 V 0.8 1 1.5 µA 0.784 0.8 0.816 V - - 100 nA CHANNEL 1(STEP-UP) Pre-OSC to OSC Trip Level Pre-OSC to OSC Hysteresis Under Voltage Lockout Input Voltage Range VCC1 VCC rising edge PVCC1 Channel 1 DC/DC Normal Operating Soft-Start Charge Current ISS1 FBU Regulation Voltage VFBU Ta=-20°C ~+85°C FBU input Current IFBU Current-Sense Amplifier Transresistance RCS - 0.285 - V/A Transconductance GMEA - 140 - µs Maximum Duty Cycle DMAX FBU=0.7V 85 90 95 % VCC =2.5V~5.5V FBU=0.8V PVCC1 Leakage Current IL1 VLXU=0V,PVCC1=5.5V - 5 12 µA LX Leakage Current ILX1 VLXU=5.5V - 1 5 µA RN N-Channel - 95 150 mΩ RP P-Channel - 150 250 mΩ Switch On-Resistance N-Channel Current Limit ILimit1 1.8 2.1 2.4 A P-Channel Turn-off Current IREV1 - 20 - mA Startup Current Limit ILimit-s PVCC1=1.5V - 450 - mA Startup Frequency fSTART PVCC1=1.5V - 200 - KHz 1.2 - 6.0 V 0.8 1 1.5 µA 0.784 0.8 0.816 V - - 100 nA CHANNEL 2(STEP-DOWN) Input Voltage Range PVCC2 Channel 2 DC/DC Normal Operating Soft-Start Charge Current ISS2 FBD Regulation Voltage VFBD Ta=-20°C ~+85°C FBD input Current IFBD Current-Sense Amplifier Transresistance RCS - 0.6 - V/A Transconductance GMEA - 140 - µs Maximum Duty Cycle DMAX FBD=0.7V - 100 - % VCC =2.5V~5.5V FBD=0.8V 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC LX Leakage Current ILX2 VLX=0~3.6V,PVCC2=3.6V - 1 5 µA RN N-Channel - 95 150 mΩ RP P-Channel - 150 250 mΩ ILimit2 1.0 1.2 1.4 A Switch On-Resistance P-Channel Current Limit N-Channel Turn-off Current /SDOK Output Low Voltage IREV2 - 20 - mA VSDOK 0.1mA into /SDOK - 0.01 0.1 V /SDOK Leakage current IL_SDOK CTLD=0V,/SDOK=5.5V - 0.1 1 µA 1.2 - 6.0 V 0.8 1 1.5 µA - - 100 nA 0.784 0.8 0.816 V 80 - - dB - 5 - MHz VOH - 1.0 - V VOL - 10 - mV Isource COMP=0.8V - -0.5 - mA - 60 - µA - -130 -80 mA 65 100 - mA CHANNEL 3 Input Voltage Range PVCC3 Channel 3 DC/DC Normal Operating Soft-Start Charge Current ISS3 VCC =2.5V~5.5V FB3 input Current IFB3 FB3=0.8V FB3 Regulation Voltage VFB3 Ta=-20°C ~+85°C, FB3=COMP3 AV DC BW AV=0dB Error Amplifier Voltage Gain Error Amplifier Frequency Bandwidth Error Amplifier Output Voltage Error Amplifier Output Source Current Output Source Current Output Sink Current Isink COMP=0.8V Isource DUTY=90%,OUT=1/2VCC Isink DUTY=0%,OUT=1/2VCC ROH OUT=-15mA - 18 30 Ω ROL OUT=15mA - 16 25 Ω 85 90 95 % - 100 - % Output On-Resistor DMAX Step-Up Mode Maximum Duty Cycle DMAX Step-Down Mode CHANNEL 4,5,6 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Input Voltage Range PVCC4 Channel 4,5,6 DC/DC 1.2 - 6.0 V 0.8 1 1.5 µA 0.784 0.8 0.816 V 0.19 0.20 0.21 V 0.98 1.00 1.02 V 80 - - dB - 5 - MHz VOH - 1.0 - V VOL - 10 - mV Isource COMP=0.8V - -0.5 - mA - 60 - µA DMAX FB_=0.7V 85 90 95 % DMAX FB5=0.1V 85 90 95 % - -130 -80 mA 65 100 - mA Normal Operating Soft-Start Charge Current FB4/5/6 Regulation Voltage FB5 Regulation Voltage for LED Driver VFB4/5/6 FB5H OVP Trip Level VFB5H Ta=-20°C ~+85°C, Error Amplifier Voltage Gain Error Amplifier Frequency Bandwidth Error Amplifier Output Voltage Error Amplifier Output Source Current ISS4/5/6 VCC =2.5V~5.5V VFB5 Ta=-20°C ~+85°C, FB_=COMP_ Ta=-20°C ~+85°C, FB5=COMP5 AV DC BW AV=0dB Isink COMP=0.8V Maximum Duty Cycle Output Source Current Output Sink Current Isource DUTY=90%,OUT=1/2VCC Isink DUTY=0%,OUT=1/2VCC ROH OUT=-15mA - 18 30 Ω ROL OUT=15mA - 16 25 Ω - 0.9 - V 0.8 1.0 1.5 µA Output On-Resistor SHORT CIRCUIT PROTECTION Threshold Voltage VTH CSCP Charge Current ICSCP CH3,CH4,CH5,CH6 CONTROL BLOCK VIH PVCC1=VCC=1.5 ~5.5V 1.1 - VCC V VIL PVCC1=VCC=1.5 ~5.5V 0 - 0.5 V VIH PVCC1 , 2=VCC=1.5 ~5.5V CTLD=VIH PVCC1 , 2=VCC=1.5 ~5.5V CTLD=VIH 1.1 - VCC V 0 - 0.5 V CTLU input Voltage CTLD input Voltage VIL 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC VIH CTL3 input Voltage VIL VIH CTL4 , 5 , 6 input Voltage VIL VIH SEL4 input Voltage VIL PVCC1 , 3=VCC=1.5 ~5.5V CTLU=VIH PVCC1 , 3=VCC=1.5 ~5.5V CTLU=VIH PVCC1 , 4=VCC=1.5 ~5.5V CTLU=VIH PVCC1 , 4=VCC=1.5 ~5.5V CTLU=VIH PVCC1 , 4=VCC=1.5 ~5.5V CTLU=CTL4=VIH PVCC1 , 4=VCC=1.5 ~5.5V CTLU=CTL4=VIH 1.4 - VCC V 0 - 0.5 V 1.4 - VCC V 0 - 0.5 V 1.4 - VCC V 0 - 0.5 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: [email protected] 8 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Typical Characteristics CH1 Efficiency VS. Load Current CH3 Efficiency VS. Load Current CH1 + CH2 Efficiency VS. Load Current CH2 Efficiency VS. Load Current CH1 + CH2 Efficiency VS. Load Current CH4 , 5 , 6 Efficiency VS. Load 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: [email protected] 9 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC CH4 , 5 , 6 Efficiency VS. Load Current CH4 , 5 , 6 Efficiency VS. Load 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: [email protected] 10 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-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] 11 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC CH3 Start-Up Waveform VBAT = 2.0V Time : 20mS/Div CTL3 , 2V/Div , DC VM=3.3V , 2V/Div , DC IoutM ,100mA/Div , DC IBAT , 1A/Div , DC CH3 Start-Up Waveform VBAT = 3.0V Time : 20mS/Div CTL3 , 2V/Div , DC VM=5.0V , 2V/Div , DC IoutM , 100mA/Div , DC IBAT , 1A/Div , DC CH1,CH2,CH3 Start-Up Waveform VBAT = 3.0V Time : 50mS/Div CTLU , 2V/Div , DC VDSP_IO=3.3V , 2V/Div , DC VDSP_Core=1.8V , 1V/Div , DC VM=5V , 5V/Div , 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] 12 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC CH1 Load Transient Response VBAT = 3.0V Time : 1mS/Div VM , 100mV/Div , AC Iout1 , 200mA/Div , DC CH2 Load Transient Response VBAT = 2.0V Time : 1mS/Div VDSP_Core , 100mV , AC Iout2 , 100mA/Div , DC CH3 Load Transient Response VBAT = 3.0V Time : 1mS/Div VDSP_IO , 100mV/Div , AC Iout3 , 100mA/Div , 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] 13 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Typical Application Circuit Multi-Battery Application 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC 2-AA Battery Application 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC 1-Li Battery Application 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Application Information The AT1396A/B/C/D include 6 channels DC/DC to generate a multiple-output digital camera power-supply system. It include: z Step-Up DC/DC converter with on-chip synchronous MOSFETs.(CH1) z Step-Down DC/DC converter with on-chip synchronous MOSFETs.(CH2) z Main synchronous DC/DC controller can be configured as either a Step-Up or Step-Down converter.(CH3) z Selectable DC/DC controller for boost/flyback/buck/inverting converters.(CH4) z White LED driver with open LED protection or boost controller.(CH5) z Boost/flyback controller.(CH6) Step-Up DC/DC Converter (CH1) The step-up DC/DC converter typically is used to generate a 5V or the highest of the DSC power system requirement from a 1.5V to 4.2V battery input and self-power the AT1396. The efficiency is up to 95% with an internal MOSFET and external synchronous rectifier. Step-Down DC/DC Converter (CH2) The step-down DC/DC is optimized for generating DSP core voltage (down to 0.8V) at high efficiency. It runs from the voltage at PVCC2. This pin can be connected directly to the battery if sufficient headroom exists to avoid dropout. It can be powered from the output of another converter (CH1 or CH3) for boost-buck operation. The CH2 also features an open-drain /SDOK output that goes low when the CH2 is in regulation. /SDOK may be used to drive an external P-MOSFET that gates 3.3V power to the DSP after the core voltage is in regulation (Figure 1). The R1,R2 and C1 is for MOSFET soft-start function to avoid the more inrush current . Step-Up or Step-Down DC/DC Converter (CH3) The CH3 can be as a step-up (AT1396B/D) or step-down (AT1396A/C) voltage mode PWM converter. An external MOSFET and synchronous rectifier allow conversion efficiencies as high as 93%. Step-down operation can be direct from Li-Ion cell if the minimum input voltage exceeds the desired output by approximately 200mV. When 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC generating 3.3V from Li-Ion, boost-buck operation may be needed so a regulated output can be maintained for input voltages above and below 3.3V. The efficiency is best than SEPIC or ZETA structure. In this case, it may be configure the CH3 as a step-down and connect its input PVCC3 to the CH1 output, set to a voltage at or above 4.2V. The output efficiency with this topology is typically up to 90%. Note that the step-up output (CH1) supplies both the step-up(CH1) load and the step-down (CH2) input current when the CH3 is powered from the CH1. The CH3 input current reduces the available step-up output (CH1) current for other loads. Figure 1. Using /SDOK to drive external MOSFET that gates 3.3V power to DSP after 1.8V core voltage is in regulation 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Auxiliary Controller (CH4,CH5,CH6) The three auxiliary controllers operate as fixed-frequency voltage-mode PWM controllers. They use the external MOSFETs, so output power is determined by external components. All of auxiliary controllers have a guaranteed duty cycle of minimum duty cycle of 85%(boost-type) or 100%(buck/inverting type). In boost designs that employ continuous current (CCM), the maximum duty cycle limits the boost ratio so: 1− V IN ≤ 85% VOUT With discontinuous inductor current(DCM), no such limit exists for the input/output ratio since the inductor has time to fully discharge before the next cycle begins. The discontinuous conduction mode boost voltage conversion relationship is given by: 1+ 1+ VO = Vi × 4 × D2 K 2 D = K × M × ( M − 1) Where K is defined as: 2×L K= R × TS M = VO Vi The CH4 is selectable DC/DC controller for drive N-channel MOSFETs (SEL=high) or P-channel MOSFETs (SEL=low). It can be configure as the inverting circuit (Figure 2), typically for CCD and LCD bias. This is useful in height-Limited designs where transformers may not be desired. The efficiency is more than the charge-pump inversion for some load conditions. The CH5 can be configure as a switching-mode boost current source for white LEDs, FB5(0.2V) provides current-sensing feedback, while FB5H(1.0V) provides (optional) open-LED over-voltage protection(Figure 3). If used as a boost converter, FB5H is grounded and FB5(0.8V) is used as the feedback input. In this case, CH5 behaves exactly like CH4 and CH6. The CH6 can be used for conventional DC/DC boost and flyback designs.(Figure 4 ,Figure 5 and Figure 6) 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Figure 2. Regulated –7.5V negative CCD Bias. Figure 3. LED Drive with open LED over-voltage protection 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Figure 4. +15V and –7.5V CCD Bias with transformer Figure 5. +15V and –7.5V CCD Bias with Charge-Pump Inversion 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 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Figure 6. +15V and –7.5V CCD Bias with Charge-Pump (using AT1202 to regulated the negative output) Soft-Start Setting (CH1~CH6) The AT1396 all channels feature a soft-start function that limits inrush current and prevents excessive battery loading at start-up by ramping the output voltage of each channel up to the regulation voltage. Consider the input voltage and load current to design the capacitor connected to the SS pin. It can calculate the CH1~6 soft start time Ts(s)(valid threshold 0.3~0.8V interval). C× ∆V =I ∆t Ts( s ) = 0.5 × C ( µF ) Note : It could be disabled soft start function by floating SS pin. 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] 22 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC SCP Protection Setting (CH3~CH6) The CSCP comparator detects CH3,CH4,CH5 and CH6 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) = 0.9 * CCSCP (μF) Note : It could be disabled short circuit protection function by connecting CSCP pin into the ground. 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. f OSC ( KHz ) = 41000 CT ( pF ) 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] 23 REVD: 05/05/23 AT1396A/B/C/D Preliminary Product Information 6-Channel DC-DC Converter for DSC Package Outline: QFN48 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] 24 REVD: 05/05/23