Ns na 25 power ics laboratory chern lin chen national

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Unformatted text preview: n University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 Primary-Side Snubber Less expensive 20 National Taiwan University 國立台灣大學 Higher efficiency Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 Secondary-Side Snubber MOS switch ON 2ndary diode OFF equivalent circuit _ + + _ 21 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Ns VDC Np VO Ns VDC Np + _ VO Chern-Lin Chen 陳秋麟 Under Voltage Lockout VDD UVLO RI OSC Green Mode GND FB SQ R OCP Gate Driver OUT Voff SENSE LEB ON OFF Vstart 22 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 UVLO R1 LDO R2 R3 VZ VF MOS OFF R2 + R3 VCC × = VZ + VF ⇒ UVLO ON / MOS OFF R1 + R2 + R3 VCC × VCC × R2 + R3 < VZ + VF ⇒ MOS ON R1 + R2 + R3 R2 = VZ + VF ⇒ UVLO OFF / MOS OFF R1 + R2 23 National Taiwan University 國立台灣大學 UVLO OFF R1 + R2 (VZ + VF ) R2 R1 + R2 + R3 (VZ + VF ) R2 + R3 VCC UVLO ON Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 UVLO Circuit R1 Voff VREF H VDD ON R2 OFF Vstart R3 L H 24 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 During Output Building Up D2 D3 Na Ns VO grows from 0 VDD drops from Vstart D3 OFF At certain instant, VO + VD 2 VDD + VD 3 = , start-up succeeds. Ns Na 25 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 National Taiwan University 國立台灣大學 Large Start-Up Resistance 2 vdc large Rin reduce loss Rin small C1 keeps RinC1 feasible 26 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 Energy-Grabbing Capacitor large C2 avoids UVLO during start-up 27 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 Turn-On Spike 28 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 RC Filtering Increase time delay (phase lag) R C 29 National Taiwan University 國立台灣大學 Power ICS Laboratory 功率積體電路與系統實驗室 Chern-Lin Chen 陳秋麟 Leading Edge Blanking 30 National Taiwan University 國立台灣大學 Power ICS Laboratory 功...
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This note was uploaded on 10/16/2010 for the course GRADUATE I Power IC taught by Professor Chern-linchen during the Fall '09 term at National Taiwan University.

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