Synchronous Buck Converter using LTspice

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Synchronous Buck Converter using LTspice

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Synchronous Buck Converter using LTspice

  1. 1. Synchronous-Buck Converter Circuit• Synchronous-Buck Converter Circuit• Test Setup• Test Circuit• Synchronous-Buck Controller• MOSFET: TPC8014• Inductor L1: Würth Elektronik Inductor• Capacitor C9: 820uF (25V)• Switching Waveform• High Side MOSFET(QH): VGS, VDS, ID• Low Side MOSFET(QL): VGS, VDS, ID• Gate Drive Signal• VIN-VOUT• VOUT,RIPPLE• Output Inductor Voltage and Current All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 1
  2. 2. Synchronous-Buck Converter Circuit Duty Cycle (D) ≈ Vin/Vout, D = 0.368 All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 2
  3. 3. Test Setup Power Supply: Measurement Waveform VCC 12V VIN 5V Test Circuit All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 3
  4. 4. Test Circuit Schematic Synchronous-Buck Converter using TPS5618 controller from Texas Instruments All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 4
  5. 5. Test Circuit (Breadboard) Q1 Q2 Controller All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 5
  6. 6. Test Circuit (Top View) L1 C9 C10 Controller All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 6
  7. 7. Synchronous-Buck Controller (1/2)Synchronous-Buck Controller Circuit with IC Synchronous-Buck Controller Block ModelTPS5618 from Texas Instruments (Open Loop Setting) HIDR High side gate driver Low side gate driver LODR• The Syn-Buck_Ctrl is a block model that generates gate drive pulse signal to control MOSFET switches of the Synchronous-Buck Converter. The duty cycle, switching frequency, and the switching dead-time are input into the model to match the real circuit. All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 7
  8. 8. Synchronous-Buck Controller (2/2) Parameters • FREQ = Switching frequency, set to match the measurement switching frequency. PARAMETERS: • D = Duty Cycle, calculated by D≈VOUT/VIN • FREQ = 152kHz D = 0.36 DHDR1 RHDR1 tdly = HDR and LDR dead-time, the tdly is U1 Dclmp 0.01 tdly = 80n AND2_ABM N7 set to match the measurement dead time Rdly 1 N4 N5 N6 HDR value. Dclmp RHDR2 CHDR Dead-time, the time 1k Cdly 1 VOH = 12 DHDR2 0.01 1n when QH and QLPulse {tdly /1k} VOL = 0 0 are both offControl 0Signal 1/frequency U5 U2 INV_ABM AND2_ABM N1 N2 Rdly 2 N3 LDR VOH = 1.709 VOL = 0 1k V1 Cdly 2 VOH = 8 {tdly /1k} VOL = 0 TD = {1/FREQ} TR = 1n 0 TF = 1n Dead-time 0 V1 = 0 V2 = 1.709 generator PW = {D/FREQ} PER = {1/FREQ} The Syn-Buck_Ctrl Equivalent Circuit Gate drive signal (measurement) All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 8
  9. 9. MOSFET: TPC8014 (1/2) *$ *PART NUMBER: TPC8014 *MANUFACTURER: TOSHIBA *VDSS=30V, ID=11A *All Rights Reserved Copyright (c) Bee Technologies Inc. 2011 .SUBCKT TPC8014 1 2 3 4 5 6 7 8 X_U1 6 4 3 MTPC8014_p X_U2 4 3 DZTPC8014 X_U3 3 6 DTPC8014_p R_R1 1 3 0.01m R_R2 2 3 0.01m R_R5 5 6 0.01m R_R7 7 6 0.01m Device mounted on an epoxy board R_R8 8 6 0.01m .ENDS *$ TPC8014 LTSpice Symbol All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 9
  10. 10. MOSFET: TPC8014 (2/2)*$ *$ .SUBCKT DTPC8014_p A K.SUBCKT MTPC8014_p D G S R_R2 5 6 100CGD 1 G 1.7n R_R1 3 4 1R1 1 G 10MEG C_C1 5 6 195pS1 1 D G D SMOD1 E_E1 5 K 3 4 1 S_S1 6 K 4 K _S1D1 2 D DGD RS_S1 4 K 1GR2 D 2 10MEG .MODEL _S1 VSWITCHS2 2 G D G SMOD1 + Roff=50MEG Ron=100m Voff=90mV Von=100mVM1 D G S S MTPC8014 G_G1 K A VALUE { V(3,4)-V(5,6) } D_D1 2 K DTPC8014.MODEL SMOD1 VSWITCH D_D2 4 K DTPC8014+ VON=0V VOFF=-10mV RON=1m ROFF=1E12 F_F1 K 3 VF_F1 1.MODEL DGD D (CJO=0.950E-9 M=.52396 VJ=.54785) VF_F1 A 2 0V.MODEL MTPC8014 NMOS .MODEL DTPC8014 D+ LEVEL=3 L=720.00E-9 W=.45 KP=66.000E-6 RS=1.0000E-3 + IS=824.87E-12 N=1.2770 RS=6.2420E-3 IKF=7.3139 + CJO=3.0000E-12 BV=60 IBV=100.00E-6 TT=24.062E-9+ RD=6.8436E-3 VTO=2.3063 RDS=3.0000E6 TOX=40.000E-9 .ENDS+ CGSO=2.7726E-9 CGDO=1E-12 RG=22.95 *$+ CBD=342.86E-12 MJ=.70573 PB=.3905 .subckt DZTPC8014 1 2+ RB=1 N=5 IS=1E-15 GAMMA=0 KAPPA=0 ETA=0.5m D2 1 3 DZ2 D1 2 3 DZ1.ENDS .model DZ1 D*$ + IS=0.01p N=0.1 ISR=0 + CJO=3E-12 BV=22.423 IBV=0.001 RS=0 .model DZ2 D + IS=0.01p N=0.1 ISR=0 + CJO=3E-12 BV=22.423 IBV=0.001 RS=411.11 .ENDS *$ All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 10
  11. 11. Inductor L1: Würth Elektronik Inductor *$ *PART NUMBER: L7447140 *MANUFACTURER: Würth Elektronik *All Rights Reserved Copyright (c) Bee Technologies Inc. 2011 .SUBCKT L7447140 1 2 R_RS 1 N1 10.366m L_L1 N1 2 4.84796uH C_C1 N1 2 0.357pF R_R1 N1 2 15.3375k .ENDS *$ Würth Elektronik Inductor part no. 7447140 LTSpice Symbol All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 11
  12. 12. Capacitor C9: 820uF (25V) *$ *PART NUMBER: EEUFM1E821L *MANUFACTURER: Panasonic *CAP=820uF, Vmax=25V *All Rights Reserved Copyright (C) Bee Technologies Inc. 2011 .SUBCKT C820U 1 2 L_L1 1 N1 8.16935nH C_C1 N1 N2 812.73uF R_R1 N2 2 15.695m .ENDS *$ Capacitor 820uF (25V) LTSpice Symbol All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 12
  13. 13. Switching WaveformMeasurement Simulation VDS(Q1) VDS(Q1) I(L1) I(L1) V(Vout) V(Vout) All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 13
  14. 14. High Side MOSFET(QH): VGS, VDS, IDMeasurement Simulation VGS(Q1) VGS(Q1) VDS(Q1) VDS(Q1) ID(Q1) ID(Q1) All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 14
  15. 15. Low Side MOSFET(QL): VGS, VDS, IDMeasurement Simulation VGS(Q2) VGS(Q2) VDS(Q2) VDS(Q2) ID(Q2) ID(Q2) All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 15
  16. 16. Gate Drive SignalMeasurement Simulation VGS(Q1) VGS(Q1) VGS(Q2) VGS(Q2) All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 16
  17. 17. VIN – VOUTMeasurement Simulation VIN VIN VOUT VOUT All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 17
  18. 18. VOUT,RIPPLEMeasurement Simulation VOUT,RIPPLE VOUT,RIPPLE All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 18
  19. 19. Output Inductor Voltage and CurrentMeasurement Simulation V(L) V(L) I(L) I(L) All Rights Reserved Copyright (C) Bee Technologies Corporation 2011 19

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