IRDC3710-QFN

IRDC3710-QFN SupIRBuck DESCRIPTION TM USER GUIDE FOR IRDC3710-QFN EVALUATION BOARD The IR3710M is a single phase sync-buck PWM controller IC optimized for efficiency in high performance portable electronics. The switching modulator uses constant ON-time control. Constant ON-time with diode emulation provides the highest light load efficiency required for all applications. Key features offered by the IR3710M include: programmable switching frequency, soft start, forced continuous conduction mode (FCCM) operation at light load and over current protection. Additional features include pre-bias startup, very precise 0.5V reference, over/under voltage fault protection, power good output, and enable input with voltage monitoring capability. The gate drive is designed to operate up to 7.5V to enhance over all system efficiency. This user guide contains the schematic and bill of materials for the IRDC3710-QFN evaluation board. The guide describes operation and use of the evaluation board itself. Detailed specifications and application information for IR3710M is available in the IR3710M data sheet. BOARD FEATURES • Vin = +12V Typical ( 8-19V input Voltage range. Pls. see note below) • PVcc= +5.0V • Vcc=+3.3V • Vout = +1.1V @ 0- 20A • Fs = 300kHz @ 20A • L = 0.5uH • Cin= 2x10uF (ceramic 1210) + 1x330uF (electrolytic) • Cout= 2x10uF (ceramic 1206) + 3x330uF(SP Cap) Note: At low input line an additional 10uF ceramic capacitor is recommended at input to handle higher ripple current) 1 IRDC3710-QFN CONNECTIONS and OPERATING INSTRUCTIONS A regulated +12V input supply should be connected to VIN+ and Vin-. A maximum 20A load should be connected to VOUT+ and VOUT-. The connection diagram is shown in Fig. 1 and inputs and outputs of the board are listed in Table I. IRDC3710-QFN has three input connectors, one for gate drive supply (PVcc),one for biasing (Vcc) and the third one as input voltage (Vin). Separate supplies should be applied to these inputs. PVcc input should be a well regulated 4.5V-5.5V supply and it would be connected to +5V and GROUND and Vcc input should be a well regulated 3.0V-3.6V supply and it would be connected to +3.3V and GROUND. An external signal can be provided as Enable signal to turn on or turn off the converter if desired. This signal is not required to power up the Evaluation board as EN pin is connected to a voltage divider from Vin. The absolute maximum voltage of Enable signal is +3.9V. The evaluation board is configured for use with 2x10uF (ceramic 1206) + 3x330uF (SP) capacitors. However, the design can be modified for an all ceramic output cap configuration by adding the inductor DCR sensing circuit as show in the schematic. Table 1: Connections Connection VIN+ VIN+5V +3.3V GROUND VOUT+ VOUT+ Enable Signal Name VIN (+12V) Ground of VIN PVcc input (+5.0V) Vcc input (+3.3V) Ground for PVcc and Vcc input Vout (+1.1V) Ground of Vout Enable input LAYOUT The PCB is a 4-layer board. All layers are 2 Oz. copper. The IR3710M and other components are mounted on the top and bottom side of the board. Power supply decoupling capacitors, the Bootstrap capacitor and feedback components are located close to IR3710M. The feedback resistors are connected to the output voltage at the point of regulation and are located close to IR3710M. To improve efficiency, the circuit board is designed to minimize the length of the on-board power ground current path. 2 IRDC3710-QFN Vin = +12V Vin- Enable PGood V out- Vcc = +3.3V PVcc = +5.0V GROUND V = +1.1V out Figure 1: Connection diagram of IRDC3710-QFN evaluation board 3 IRDC3710-QFN Figure 2: PCB layout, top layer Figure 3: PCB layout, bottom layer 4 IRDC3710-QFN Figure 4: Board layout, mid-layer I Figure 5: Board layout, mid-layer II 5 IRDC3710-QFN 6 Figure 6: Schematic of the IRDC3710-QFN Evaluation board IRDC3710-QFN Bill of Materials Item Number 1 2 3 4 5 6 7 8 Quanti ty 4 1 1 2 1 1 3 2 Part Reference C1 C2 C3 C4 C5 C7 C8 C9 C10 C12 C13 C14 C15 C16 C17 C11,C18,C2 0,C22 C21,23,C24, C25 9 10 11 12 13 14 15 1 1 1 1 1 1 4 C19 D1 D2 L1 Q1 Q2 R13 R17 R18 R4 16 17 18 19 1 1 1 3 R5 R7 R12 R14 R19 R9,R11,R16 20 21 22 1 1 1 R15 SW1 U1 22000pF BAT54S BAS316 500nH IRFH7921PbF IRFH7932PbF 10K 48.7K 180K 7..5K 1.96K 0 N/S 1.65K Switch, 2-Pos. IR3710MPbF Thick-film,0603,1/10W,1% Switch, DIP, 2-Pos., SPDT IR3710, Controller,PQFN,3x3mm Panasonic - ECG Copal Electronics Inc International Rectifier ERJ-3EKF1651V CJS-1200TB IR3710MPbF Value 0.1uF 2.2uF 1.0uF 10uF 330uF 1.0uF 330uF 10uF Description Manufacturer1 Murata Electronics North America Murata Electronics North America Taiyo Yuden Taiyo-Yuden Panasonic Murata Electronics North America Panasonic Murata Electronics North America Manufacturer Part Number GRM188R61E105KA12D GRM185R60J225KE26D TMK212BJ105KG-T TMK325BJ106MN-T EEE-FK1E331P GRM188R61E105KA12D EEFUE0G331XE GRM21BCB0G106ME19F Ceramic,25V,0603,X7R,10% Ceramic, 6.3V, 0603, X7R, 10% Ceramic, 25V, 0805, X5R, 10% Ceramic,25V,1210,X5R,10% SMD Electrolytic, 25V, F-size,20% Ceramic,25V,0603,X5R,10% SP-Cap,Dcase,4V,20% Ceramic,6.3V,1206,X5R,20% N/S N/S Ceramic,50V,0603,X7R,10% Diode,40V,BAT54S,SOT-23 Diode 75V , 0.25A, SOD323 SMT-Inductor, 0.8mOhm,12.1x13.4mm,20% Mosfet 30V 8.5mOhm PQFN Mosfet 30V 3.3mOhm PQFN Thick-film,0603,1/10W,1% Thick-film,0603,1/10W,1% Thick-film,0603,1/10W,1% Thick-film,0603,1/10 W,1% Thick-film,0603,1/10W,1% Thick-film,0603,1/10 W,5% TDK Corporation Diodes, Inc. NXP Toko International Rectifier International Rectifier Vishay/Dale Rohm Rohm Rohm Rohm Vishay/Dale C1608X7R1H223K BAT54S BAS316 FDUE1245-R50M IRFH7921PbF IRFH7932PbF CRCW060310K0FKEA MCR03EZPFX4872 MCR03EZPFX1803 MCR03EZPFX7501 MCR03EZPFX1961 CRCW06030000Z0EA 7 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V,Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow Ch1-Phase Voltage(10V/Div) Ch3-CPO(2V/Div) Ch2-Vout(50mV/div) Time: 10uS/Div) Ch1-Phase Voltage(10V/Div) Ch3-CPO(2V/Div) Ch2-Vout(50mV/div) Time: 2uS/Div) Figure 7: Charge Pump Off at Iout = 0.5A Figure 8: Charge Pump On at Iout =5A Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Figure 9: Load Step (5A to 15A) Transient at 12Vin Figure 10: Load Step (5A to 15A) Transient at 19Vin 8 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V,Vo=1.1V, Io=0- 20A, Room Temperature, No Air Flow Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Figure 11: DCM/CCM transition from 1.0A to 5A at 12Vin Figure 12: DCM/CCM transition from 1.0A to 5A at 19Vin Ch1-Phase Voltage (10V/Div) Ch3-EN(2V/Div) Ch2-Vout(500mV/Div) Ch4-PGood(2V/Div) Ch1-Phase Voltage (10V/Div) Ch3-EN(2V/Div) Ch2-Vout(500mV/Div) Ch4-PGood(2V/Div) Figure 13: Startup/Shutdown 12Vin at 0.5A Figure 14: Startup/Shutdown 12Vin at 5.0A 9 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow 92 90 88 86 Efficiency(%) 84 5 4.5 4 3.5 3 2.5 Power Loss(W) Power Loss(W) 82 2 80 78 76 74 0 4 8 Iout(A) Eff 12V Input CP ON Power Loss 12V Input CP ON Eff 12V input CP OFF Power Loss 12V Input CP OFF 12 16 20 1.5 1 0.5 0 Figure 15: Typical Efficiency and Power Loss at Vin-12V 5 90 4.5 4 80 Efficiency(%) 3.5 3 70 2.5 60 2 1.5 50 1 0.5 40 0 4 8 12 16 Eff 19V Input CP ON Eff Iout(A) 8V Input CP ON Power Loss 19V Input CP ON Power Loss 8V Input CP ON 20 0 Figure 16: Typical Efficiency and Power Loss at Vin=8V and 19V 10 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow 1.1060 1.1040 1.1020 1.1000 Vout(V) 1.0980 1.0960 1.0940 1.0920 12V Input 1.0900 0 4 8 Iout(A) 12 16 20 8V Input 19V Input Figure 17: Typical Output Voltage Regulation Q1: 73.2°C, Q2:83.2°C, IC-64.2°C,Inductor: 53.5°C, PCB: 53.3°C Figure 18:Thermal Image @12Vin, 20A, With CP On 11 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow Q1: 82.5°C, Q2:94.8°C, IC-69.7°C,Inductor: 58.1°C, PCB: 56.4°C Figure 19: Thermal Image @19Vin, 20A, With CP On Q1:83.2°C,Q2:91.2°C, IC-68.7°C, Inductor: 57.1°C, PCB: 55.9°C Figure 20: Thermal Image @12Vin, 20A, With CP Off 12 IRDC3710-QFN PACKAGE INFORMATION 13