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Role of Capacitor [3]
Copyright. SAMSUNG ELECTRO-MECHANICS All rights reserved. SAMSUNG Role of Capacitor [1] Overview of Capacitor Role [2] Noise Filtering caused by IC Switching [3] Noise Filtering caused by Converter Switching [4] Power Delivery Network SAMSUNG Power Conversion: IC (1) Suitable Power Conversion for IC is required - [Smartphone] A battery supplies voltage to IC through DC-DC converter [Power Source Conversion] [Power in Smartphone] Most of ICs need DC voltage, DC voltage level varies with IC. SAMSUNG Power Conversion: IC (2) PMIC consists ed. - [Smartphone] A battery supplies voltage to IC through DC-DC converter Voltage Regulator → Linear Regulator, Switching Regulator(DC-DC converter), Charge Pump → LDO Regulator, Buck Converter, Boost Converter, Buck-Boost Converter LDC / Voltage - Vin > Vout / Efficiency - Low / Cost - Low / Noise - Low / Application - Low Power, Noise / Needed Components - Capacitor Buck Converter / Voltage - Vin > Vout / Efficiency - High / Cost - High / Noise - High / Application - High Power / Needed Components - Power Inductor, Capacitor Boost Converter / Voltage - Vin < Vout / Efficiency - High / Cost - High / Noise - High / Application - High Power / Needed Components - Power Inductor, Capacitor Buck-Boost Converter / Voltage - Vin >< Vout / Efficiency - High / Cost - High / Noise - High / Application - High Power / Needed Components - Power Inductor, Capacitor Charge Pump / Voltage - Vin < Vout / Efficiency - Middle / Cost - Middle / Noise - Middle / Application - Mid Power / Needed Components - Capacitor SAMSUNG Filtering of Converter Switching Noise (1) A capacitor performs a role of suppressing the voltage change - Buck Converter ※Step-down converter → Vin: Battery 4V, Vout: Low Voltage for IC ※ Analysis by static Load L (X) C (X) - Pulse Voltage by PMIC switching, Vo is determined by the duty ration ※ Duty ration = ton/(ton+toff) L (O) C (X) - An Inductor performs suppressing the current change → Triangle voltage waveform (Same as current waveform) L (O) C (O) - A Capacitor performs a role of suppressing the voltage change → Reduction of voltage ripple (ΔV) SAMSUNG Filtering of Converter Switching Noise (2) Smaller capacitance of a capacitor can increase voltage fluctuactions - Vout according to C # Buck Converter - Frequency: 3MHz, Vin: 4V / V out: 1V, Duty ration = 25% SAMSUNG Filtering of Converter Switching Noise (3) Higher ESR of Capacitor can increase voltage fluctuations - Vout according to ESR # Buck Converter - Frequency: 3MHz, Vin: 4V / V out: 1V, Duty ration = 25% SAMSUNG Filtering of Converter Switching Noise (4) Higher ESR of Capacitor can increase voltage fluctuations - Vout according to ESR # Buck Converter - Frequency: 3MHz, Vin: 4V / V out: 1V, Duty ration = 25% Copyright. SAMSUNG ELECTRO-MECHANICS All rights reserved.