Role of Capacitor [3] |
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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
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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.
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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
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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)
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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%
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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%
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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. |