ACT4455 | DigiCamel IC Datasheet

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ACT4455 ACTIVE-SEMI | Alldatasheet

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Manufacturer or author: Provided By alldatasheet.com(free datasheet download site)
PDF pages: 15

Technical content

FEATURES

7.5V to 36V Input Voltage
40V Input Voltage Surge
Up to 5A Output Current
Up to 12V Output Voltage
Dual Outputs with Independent Over Current Protection
7.5% Accurate Over Current Protection (OCP)
Integrated 45mΩ High Side Power FET
90% Efficiency at Heavy Load
Internal 3ms Soft Startup
Low Standby Input Current
Sleeping Mode at OCP, OTP and SCP
Zero Input and Output Currents at Over Current and Short Circuit Protection
Auto Recovery into Full Load after Faults
Output Cord Voltage Drop Compensation
Stable with Low ESR Ceramic Output Capacitors
Internal Cycle-by-Cycle Current Control
Programmable Over Current Setting
SOP-8EP Package

APPLICATIONS

Automotive Industry
Dual-Output Car Charger
LCD-TV GENERAL DESCRIPTION ACT4455 is a wide input voltage step-down DC/DC converter with high-side MOSFET integrated. It provides up to 5A continuous output current at 200kHz switching frequency. The converter can be configured as single output or dual outputs with independent over current protection. The converter achieves high efficiency and excellent load and line regulation. The converter enters into hiccup and sleeping mode and the converter power consumption is nearly zero when output is overloaded or shorted to ground. Other protection features includes cycle-by-cycle current limit, under voltage protection and thermal shutdown. The device is available in SOP8-EP package. ACT4455 36V/5A Step Down DC/DC Converter Rev 2, 21-Nov-12 ACT4455-001 Output current (V) Efficiency (%) 0 1000 2000 3000 4000 5000 100 Efficiency vs. Load current VIN = 24V VIN = 12V VIN = 32V

ORDERING INFORMATION

PART NUMBER OPERATION TEMPERATURE RANGE PACKAGE PINS PACKING ACT4455YH-T -40°C to 85°C SOP-8EP 8 TAPE & REEL PIN CONFIGURATION PIN DESCRIPTIONS PIN NAME DESCRIPTION 1 CS1 The output current of VOUT1 is sensed by this pin. When the voltage on this pin reaches 116mV for 750µs, the IC shuts down for 2.5 seconds before initiating a restartup. 2 SW Switch Output. Connect this pin to t he switching end of the external inductor. 3 HSB High Side Bias. This pin acts as the positive rail for the high-side switch’s gate driver. Connect a 22nF-100nF capacitor between HSB and SW pins. 4 GND Ground. 5 COMP Compensation Node. COMP is used to compensate the voltage regulation loop. 6 FB Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a resistive voltage divider from the output voltage. The feedback threshold is 0.808V. See Setting the Output Voltage. 7 IN Input Supply. Bypass this pin to GND with a 10µF or greater low ESR capacitor. 8 CS2 The output current of VOUT2 is sensed by this pin. When the voltage on this pin reaches 116mV for 750µs, the IC shuts down for 2.5 seconds and then restarts. Exposed Pad Exposed Pad. Connect this p ad to thick copper plane via copper vias.

Rev 2, 21-Nov-12 Innovative PowerTM - 3 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ABSOLUTE MAXIMUM RATINGSc PARAMETER VALUE UNIT IN to GND -0.3 to 44 V SW to GND -0.3 to V IN + 0.3 V HSB to GND V SW - 0.3 to VSW + 7 V FB, CS1, CS2, COMP to GND -0.3 to + 6 V Junction to Ambient Thermal Resistance 50 °C/W Operating Junction Temperature -40 to 150 °C Storage Junction Temperature -55 to 150 °C Lead Temperature (Soldering 10 sec.) 300 °C c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rati ng conditions for long periods m ay affect device reliability.

Rev 2, 21-Nov-12 Innovative PowerTM - 4 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. PARAMETER SYMBOL TEST COND ITIONS MIN TYP MAX UNIT Feedback Voltage V FB 7.5V ≤ VIN ≤ 40V 798 808 818 mV Error Amplifier Voltage Gain A EA 4000 V/V Error Amplifier Transconductance G EA ∆ICOMP = ± 10µA 650 µA/V Over Voltage Protection Threshold V OVP 41 V Max E/A Source Current I SRCMAX V FB = 0.5V 120 µA Max E/A Sink Current I SINKMAX V FB = 1.0V 120 µA High-Side Switch ON-Resistance R DS(ON)1 At 25°C 38 m Ω Low-Side Switch ON-Resistance R DS(ON)2 5 Ω Maximum Duty Cycle D MAX 80 % Switching Frequency F SW 180 200 220 kHz Upper Switch Current Limit I LIM Duty Cycle = 65% 6.5 A COMP to Current Limit Transconductance GCOMP 5 A/V Minimum on Time T ON_MIN 250 ns Input Under Voltage Lockout Thresh- old VIN_Rise V IN Rising 6.75 7 7.25 V Input Under Voltage Lockout Hystere- sis VIN_Falling V IN Falling 650 mV Internal Soft Startup Time T SS 3.0 ms CS1 reference voltage V CS1 113 116 119 mV CS2 reference voltage V CS2 113 116 119 mV Frequency Foldback Threshold V FB_Foldback 0.65 V Cord Compensation VIN = 12V, RFB1=200k, IOUT = 5A 0.35 V Thermal Shutdown 150 °C

ELECTRICAL CHARACTERISTICS

(VIN = 12V, TA = 25°C, unless otherwise specified.)

Rev 2, 21-Nov-12 Innovative PowerTM - 5 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. FUNCTIONAL BLOCK DIAGRAM FUNCTIONAL DESCRIPTION Operation As seen in Functional Block Diagram, the ACT4455 is a current mode controlled regulator. The EA output voltage (COMP voltage) is proportional to the peak inductor current. A switching cycle starts when the rising edge of the Oscillator clock output ca uses the High-Side Power Switch to turn on and the Low-Side Power Switch to turn off. With the SW side of the inductor now connected to IN, the inductor current ramps up to store energy. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higher than the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Os cillator clock output goes low, the High-Side Power Switch turns off and the inductor freewheels through the schottky diode causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. The High-Side Power Switch is driven by logic using HSB as the positive rail. This pin is charged to V SW + 5V when the Low-Side Power Switch turns on. The Comp voltage is the integration of the error between FB input and internal 0.808V reference. If FB is lower than the reference voltage, COMP tends to go higher to increase current to the output. Over Current and Short Circuit Protection CS pins are connected to the high side of current sensing resistors to prev ent output over current. With independent CS1 and CS2 pins, two output currents are detected. If the voltage at either CS pins exceeds 116mV for more than 750µs. The converter shuts down and goes into sleeping mode. A new soft startup is triggered after 2.5s. If the fault condition is un-cleared, the converter shuts down again until over current condition is cleared. With this long-waiting-time hiccup mode, the power consumption at over loading or outputs short is reduced to nearly zero. Thermal Shutdown The ACT4455 shuts down when its junction temperature exceeds 150°C. The converter triggers a soft-start when the temperature has dropped by 10°C. The soft-restart avoi ds output over voltage at thermal hiccup.

Rev 2, 21-Nov-12 Innovative PowerTM - 7 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. APPLICATIONS INFORMATION CONT’D current. In that case, the output capacitor is chosen to have sufficiently low ESR. For ceramic output capacitor, typically choose a capacitance of about 22µF. For tantalum or electrolytic capacitors, choose a capacitor with less than 50mΩ ESR. Rectifier Diode Use a Schottky diode as the rectifier to conduct current when the High-Side Power Switch is off. The Schottky diode must have current rating higher than the maximum output current and a reverse voltage rating higher than the maximum input voltage.

Rev 2, 21-Nov-12 Innovative PowerTM - 8 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. STABILITY COMPENSATION Figure 2: Stability Compensation c: CCOMP2 is needed only for high ESR output capacitor The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 2. The DC loop gain of the system is determined by the following equation: The dominant pole P1 is due to C COMP: The second pole P2 is the output pole: The first zero Z1 is due to R COMP and CCOMP: And finally, the third pole is due to R COMP and CCOMP2 (if CCOMP2 is used): The following steps should be used to compensate the IC: STEP 1. Set the cross over frequency at 1/10 of the switching frequency via RCOMP: STEP 2. Set the zero f Z1 at 1/4 of the cross over frequency. If RCOMP is less than 15k Ω, the equation for CCOMP is: If R COMP is limited to 15k Ω, then the actual cross over frequency is 6.36 / (VOUTCOUT). Therefore: STEP 3. If the output capacitor’s ESR is high enough to cause a zero at lower than 4 times the cross over frequency, an additional compensation capacitor C COMP2 is required. The condition for using CCOMP2 is: And the proper value for CCOMP2 is: Though C COMP2 is unnecessary when the output capacitor has sufficiently low ESR, a small value CCOMP2 such as 100pF may improve stability against PCB layout parasitic effects. Table 1 shows some calculated results based on the compensation method above. Table 1: Typical Compensation for Different Output Voltages and Output Capacitors c: CCOMP2 is needed for high ESR output capacitor. Output Cable Resistance Compensation To compensate for resistive voltage drop across the charger's output cable, the ACT4455 integrates a simple, user-programmable cable voltage drop compensation using the impedance at the FB pin. Use the curve in Figure 3 to choose the proper feedback resistance values for cable compensation. R FB1 is the high side resistor of voltage divider. c (8) COMPVEA OUT VDC GAI V808.0A = (9) COMPVEA EA CAπ2 Gf = (10) OUTOUT OUT CVπ2 If = (11) COMP1COMP CR2 1f π= (12) COMP2COMP 3P CRπ2 1f = (13) (Ω) OUTOUT 8 CV1048.0 ×= V808.0GG10 fCV2R COMPEA SWOUTOUT COMP ×= π (14) (F) COMP COMP R 1018.3C −×= OUTOUT COMP CV1067.6C −×= (F) (15) ⎛ ××≥ OUT OUT ESRCOUT V012.0,C 101.1MinR (16) (Ω) (17) COMP ESRCOUTOUT 2COMP R RCC = VOUT C OUT R COMP C COMP C COMP2 c 2.5V 47 μF SP CAP 5.6k Ω 5.6nF None 3.3V 47 μF SP CAP 7.5k Ω 4.7nF None 5V 47 μF SP CAP 11k Ω 3.3nF None 2.5V 680 μF/6.3V/30mΩ 15k Ω 3.3nF 220pF 3.3V 680 μF/6.3V/30mΩ 15k Ω 3.3nF 220pF 5V 680 μF/6.3V/30mΩ 15k Ω 4.7nF 220pF

Rev 2, 21-Nov-12 Innovative PowerTM - 10 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. Figure 5: Typical Application Circuit for 5V/4.2A Dual-output Car Charger Table 2: BOM List for 5V/4.2A Dual-output Car Charger ITEM REFERENCE DESCRIPTION MANUFACTURER QTY

1 U1 IC ACT4455YH, SOP-8EP Active-Semi 1

2 C1 Capacitor, Electrolytic, 150µF/50V, 8×8mm Koshin 1

3 C2 Capacitor, Electrolytic, 680µF/10V, 8×11.5mm Koshin 1

4 C3 Capacitor, Ceramic, 10µF/50V, 1206, SMD Murata, TDK 1

5 C4 Capacitor, Ceramic, 4.7nF/25V, 0603, SMD Murata, TDK 1

12 L1 Inductor, 18µH, 5A, 20%, DIP Electronic-Magnetics 1

13 D1 Diode, Schottky, 45V/10A, V10L45 Vishay 1

14 R1, R2 Chip Resistor, 50m Ω, 1206, 1% Murata, TDK 2

15 R3 Chip Resistor, 9.7k Ω, 0603, 1% Murata, TDK 1

16 R4 Chip Resistor, 51k Ω, 0603, 1% Murata, TDK 1

17 R5 Chip Resistor, 15k Ω, 0603, 5% Murata, TDK 1

18 R6 Chip Resistor, 5.1 Ω, 1206, 5% Murata, TDK 1 7 C6 Capacitor, Ceramic, 2.2nF/25V, 0603, SMD Murata, TDK 1

6 C5 Capacitor, Ceramic, 220pF/25V , 0603, SMD (Optional) Murata, TDK 1

8 C7 Capacitor, Ceramic, 1000pF/25V, 0603, SMD (Optional) Murata, TDK 1

9 C8 Capacitor, Ceramic, 100pF/25V , 0603, SMD (Optional) Murata, TDK 1

10 C9 Capacitor, Ceramic, 2200pF/25V, 0805, SMD Murata, TDK 1

11 C10 Capacitor, Ceramic, 2.2µF/16V, 0603, SMD Murata, TDK 1

Rev 2, 21-Nov-12 Innovative PowerTM - 11 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 7, RCS1 = RCS2 = 50mΩ, L = 18µH, CIN = 150µF, COUT = 680µF, TA = 25°C, unless otherwise specified.) Input Voltage (V) 5 10 15 20 25 40 30 35 ACT4455-004 Switching Frequency vs. Input Voltage Switching Frequency (kHz) 250 200 150 100 ACT4455-005 Switching Frequency vs. Feedback Voltage Switching Frequency (kHz) 250 200 150 100 Feedback Voltage (mV) 0 0.2 0.4 0.6 0.8 1 ACT4455-007 Standby Current vs. Input Voltage Standby Current (µA) 940 880 860 840 820 800 900 920 Input Voltage (V) 5 10 15 20 25 40 30 35 Maximum Peak Current vs. Duty Cycle 8.5 7.5 6.5 PK Current limit (mA) Duty cycle ACT4455-006 ACT4455-008 Input Current (mA) Input Voltage (V) 5 10 15 20 25 30 35 40 Input Current vs. Input Voltage at No Load ACT4455-002 Output current (V) Efficiency (%) 0 1000 2000 3000 4000 5000 100 Efficiency vs. Load current VIN = 24V VIN = 12V VIN = 32V

Rev 2, 21-Nov-12 Innovative PowerTM - 12 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Circuit of Figure 7, RCS1 = RCS2 = 50mΩ, L = 18µH, CIN = 150µF, COUT = 680µF, TA = 25°C, unless otherwise specified.) Vcs vs. Temperature ACT4455-010 Start Up ACT4455-011 VOUT = 5V RLORD = 1.5Ω IISET = 2A VIN = 12V CH1: VOUT, 2V/div CH2: VIN, 5V/div TIME: 1ms/div CH1 CH2 VIN = 12V IOUT = 1A CH1: Ripper, 50mV/div CH2: SW, 10V/div TIME: 2µs/div SW vs. Output Ripples ACT4455-012 CH1 CH2 VIN = 12V IOUT = 0A Load Step Waveforms ACT4455-014 CH1 CH2 CH1: VOUT Ripple, 200mV/div CH2: IOUT, 2A/div TIME: 400µs/div VIN = 12V IOUT1 = 0.08-2.1A IOUT2 = 0A ACT4455-009 Input Current at Output Short Output Input Current (mA) 1.2 0.8 0.6 0.4 0.2 Input Voltage (V) 5 10 15 20 25 30 35 40 Temperature (°C) -25 0 25 50 75 100 125 150 Vcs (V) 0.18 0.17 0.16 0.15 0.14 0.13 VCS1 VCS2 CH1: Ripper, 50mV/div CH2: SW, 10V/div TIME: 2µs/div SW vs. Output Ripples ACT4455-013 CH1 CH2 VIN = 12V IOUT = 4.2A

Rev 2, 21-Nov-12 Innovative PowerTM - 13 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Circuit of Figure 7, RCS1 = RCS2 = 50mΩ, L = 18µH, CIN = 150µF, COUT = 680µF, TA = 25°C, unless otherwise specified.) ACT4455-016 Short Circuit CH1 CH2 CH1: VOUT, 5V/div CH2: IL, 2A/div CH3: SW, 10V/div TIME: 400µs/div CH3 VIN = 12V IOUT1 = 2.1A IOUT2 = 0A ACT4455-017 Short Circuit CH1 CH2 CH1: VOUT, 5V/div CH2: IL, 2A/div CH3: SW, 10V/div TIME: 400µs/div CH3 VIN = 12V IOUT1 = 2.1A IOUT2 = 2.1A Short Circuit Recovery ACT4455-018 CH1 CH2 CH1: VOUT, 2V/div CH2: IL, 2A/div CH3: SW, 10V/div TIME: 1ms/div CH3 VIN = 12V IOUT1 = 2.1A IOUT2 = 0A ACT4455-019 Short Circuit Recovery CH1 CH2 CH1: VOUT, 2V/div CH2: IL, 2A/div CH3: SW, 10V/div TIME: 1ms/div CH2 VIN = 12V IOUT1 = 2.1A IOUT2 = 2.1A Hiccup Mode ACT4455-020 CH1 CH2 CH1: VOUT, 5V/div CH2: SW, 5V/div TIME: 1s/div VIN = 12V IOUT1 = 2.1A IOUT2 = 2.1A CH1: VOUT Ripper, 200mV/div CH2: IOUT, 2A/div TIME: 400µs/div Load Step Waveforms ACT4455-015 CH1 CH2 VIN = 12V IOUT1 = 0-2.1A IOUT2 = 2.1A

Rev 2, 21-Nov-12 Innovative PowerTM - 14 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Circuit of Figure 7, RCS1 = RCS2 = 50mΩ, L = 18µH, CIN = 150µF, COUT = 680µF, TA = 25°C, unless otherwise specified.) ACT4455-022 Input Surge CH1 CH2 CH1: VIN, 10V/div CH2: VOUT Ripper, 200mV/div TIME: 10ms/div VIN = 8V-40V IOUT1 = 2.1A IOUT2 = 2.1A ACT4455-021 Input Surge VIN = 24V VOUT = 5V IISET = 2.1A CH1 CH2 CH1: VIN, 10V/div CH2: VOUT Ripper, 200mV/div TIME: 10ms/div VIN = 8V-40V IOUT1 = 2.1A IOUT2 = 0 A

Rev 2, 21-Nov-12 Innovative PowerTM - 15 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. PACKAGE OUTLINE SOP-8EP PACKAGE OUTLINE AND DIMENSIONS SYMBOL DIMENSION IN MILLIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 1.350 1.700 0.053 0.067 A1 0.000 0.100 0.000 0.004 A2 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 c 0.170 0.250 0.007 0.010 D 4.700 5.100 0.185 0.200 D1 3.202 3.402 0.126 0.134 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 E2 2.313 2.513 0.091 0.099 e 1.270 TYP 0.050 TYP L 0.400 1.270 0.016 0.050 θ 0° 8° 0° 8° Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. User s should evaluate each product to make sure that it is suitable for their applicat ions. Active-Semi products are not intended or authorized for use as critical components in life-support dev ices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact sales@active-semi.com or visit http://www.active-semi.com. is a registered trademark of Active-Semi.

Product Information

ACT4455 specifications and overview.

Summary

36V/5A Step Down DC/DC Converter Rev 2, 21-Nov-12

Description

36V/5A Step Down DC/DC Converter Rev 2, 21-Nov-12

Source title ACT4455 Datasheet(PDF) - Active-Semi, Inc

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