lecture-1 ee5325 power management integrated …...vlsi power management deals with mainly low/mid...

Lecture-1

EE5325 Power Management Integrated Circuits

Dr. Qadeer Ahmad Khan

Integrated Circuits and Systems Group

Department of Electrical Engineering

IIT Madras

1EE5325 Power Management Integrated CircuitsIntegrated Circuits and Systems Group, Department of EE, IIT Madras

What is Power Management?

Deals with Efficient and Reliable Power Delivery to a system Voltage conversion from one power domain to other

– DC-DC Conversion (Regulators)

– AC-DC/DC-AC Conversion (Rectifiers/Inverters)

Voltage/Current Measurement– Voltage and Current Sensing

Managing Losses or Heat– Current de-rating

– Dynamic Voltage Scaling (DVS)

2

Time

Voltage

CPU Performance

EE5325 Power Management Integrated CircuitsIntegrated Circuits and Systems Group, Department of EE, IIT Madras

What is Power Management?

Deals with Efficient and Reliable Power Delivery to a system Voltage conversion from one power domain to other

– DC-DC Conversion (Regulators)

– AC-DC/DC-AC Conversion (Rectifiers/Inverters)

Voltage/Current Measurement– Voltage and Current Sensing

Managing Losses or Heat– Current de-rating

– Dynamic Voltage Scaling (DVS)

3

Time

Voltage

CPU Performance

Achieved by controlling or managing power delivered to load


Types of Power Management

High Power:

100s to KWatts range powered by direct AC

Discrete semiconductor devices (FETs, BJTs, diodes) and large passives

Low/Mid Power:

mWatts to 10s of Watts powered from battery

Integrated controller & power FETs with few small external passives

4

Source: ST Microelectronics


Types of Power Management

High Power:

100s to KWatts range powered by direct AC

Discrete semiconductor devices (FETs, BJTs, diodes) and large passives

Low/Mid Power:

mWatts to 10s of Watts powered from battery

Integrated controller & power FETs with few small external passives

VLSI Power Management deals with mainly Low/Mid power applications

Source: ST Microelectronics


Need of Integrated Power Management

Power demand is increasing while board space is shrinking

PMIC: 6mm x 6mm, 225 pins

Samsung Galaxy S4

Source: chipworks

15m

m


Application of DC-DC Converters

7

Wearables- Ultra Low Power Circuits- Sensors

LED Lightings- Current Drivers

PCs, Laptops- Processor- Memories- Serial Links- Battery Chargers

Cellphones- Processor- RF Power Amp- Battery Charger- Display Backlighting- Camera Flash LED- Battery Management

Energy Harvesting

Thermal VibrationSolar RF


Application of DC-DC Converters

8

Wearables- Ultra Low Power Circuits- Sensors

LED Lightings- Current Drivers

PCs, Laptops- Processor- Memories- Serial Links- Battery Chargers

Cellphones- Processor- RF Power Amp- Battery Charger- Display Backlighting- Camera Flash LED- Battery Management

Energy Harvesting

Thermal VibrationSolar RF

Power delivery for these applications is mostly met by DC-DC Converters


Applications in Self Powered Sensors

Targeted for ultra low power applications – IoT

Highly efficient, miniaturized low power converters

Energy is harvested from freely available sources such as light, vibration, heat, RF

Structural Health Monitoring

Powering Sensors from Mechanical

Vibration

Wireless Charging

Health Monitoring Systems

Powering Sensors from Body

Heat

Implantable Biomedical

Charging Battery from Heart

Beat

Wireless Charging


Vo

ltag

e (

V)

State-of-Charge (SoC)

100% 50% 0%

DC-DC Power Converter

Converts voltage from one domain to other

Provides regulated output voltage– Under varying conditions (input voltage, output current)

DC-DC Converter

RLOAD

VOUTVIN

(Varying) (Constant)


Discrete Vs. Integrated Power Converters

Discrete Integrated

VLSI Systems mostly use Integrated DC-DC Converters due to limited board space


DC-DC Converter Types

Inductive or Capacitive

Can generate output voltage

less, greater, inverting or equal

to input voltage .

Low Drop-Out (LDO) Regulators


only less or equal to input

voltage.

Switching Linear

DC-DC Converter


DC-DC Converter Types

Inductive or Capacitive


less, greater, inverting or equal

to input voltage .

Low Drop-Out (LDO) Regulators


only less or equal to input

voltage.

Switching Linear

DC-DC Converter


Recent Trends in Power Management ICs for VLSI Systems Copyright 2019 Integrated Circuits & Systems Group @ IIT Madras

14

Switching vs Linear Regulator

Switching Regulator

Regulation achieved by changing on/off time

Switches are in either linear or cutoff reduced losses

High efficiency over wide range of VO/VIN

Linear Regulator

Regulation achieved by dropping voltage

Switches are in saturation higher losses

Poor efficiency when VO/VIN ratio is low

CO

VIN

IO

RO

VDROP

VO

MP

+

-

VREF

VOL

CO

VIN

SP

VSW

VPWMIO

ROIL

14


15


Switching Regulator




VOL

CO

VIN

SP

VSW

VPWMIO

ROIL

More than 90% of power requirement is met by Switching Converters

15


16

Switching Vs Linear Regulator

For Vin = 5V, Vo = 1V and ILoad = 1A

– 80% power loss in the Linear regulator as compared to 10% in switching regulator

For Vin = 5V, Vo = 4V and ILoad = 1A

– 20% power loss in linear regulator as compared to 2.5% in switching regulator

90

95 96.67 97.5

20

40

60

80

20

30

40

50

60

70

80

90

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Eff

icie

nc

y (

%)

VO (V)

Linear vs Switching Regulator

Switching

Linear

PowerInput

PowerOutputEfficiency )(

16


Switching Regulator




Linear Regulator

Regulation achieved by dropping voltage

Switches are in saturation higher losses

Poor efficiency when VO/VIN ratio is low

VOL

CO

VIN

SP

VSW

VPWMIO

ROIL

17

CO

VIN

IO

RO

VDROP

VO

MP

+

-

VREF


How to Choose Between Linear Vs Switching

Cost– Linear Regulators are cheaper compared to switching

Power– In a multi-power domain, linear regulator are preferred over

switching regulators for low power domains

– Switching regulators are preferred for high power applications

Conversion Ratio (Vout/Vin)– Efficiency of linear regulators is comparable to switching for higher

Vout/Vin (>0.9)

– Switching regulators are preferred when Vout/Vin is less

Noise– Linear regulators are quiet compared to switching hence preferred

over switching for noise sensitive applications such as RF, sensors and other analog circuitries


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