Automotive Infotainment Power 1 Agenda Infotainment Overview Regulation Options ON Semiconductor Solutions Example Applications System Power Architecture Design Examples • • • • • 2 Automotive Infotainment System Tuner 5.0 V 8.0 V Keyboard HS Loads Power Antenna LS Loads High Side Driver Smart High Side Driver Smart Low Side Driver Voltage Regulation (Linear, Switched) Audio Amp 7.0 V 1.8 V 3.3 V 5.0 V 5.0 V SB 7.0 V 8.0 V 8.5 V 64 V 2.0 – 10 V AUX Input Supervisory Audio Amp MCU 5.0 V SB 5.0 V SB LCD Backlighting Display VFD Driver Subwoofer Amp Vehicle Networking 5.0 V SB DSP 5.0 V 3.3 V 1.8 V Multiplexer Local Networking Audio Amp Video 2.0 – 10 V 5.0 V 64 V Audio Amp Line Driver I/O Protection L Rear Seat DVD 2.5 V 5.0 V 3.3 V 3 Single / 6-CD 8.0 V 3.3 V 8.0 V 5.0 V Line Driver R Key Infotainment Features • Many output voltages • Low power stand-by, “always on” supplies – Low Iq LDOs (NCV861X) • Higher power supplies during full operation – Switched-Mode Power Supplies (SMPS) • Drive towards less power dissipation, higher efficiency – Necessitates more SMPS, upstream vs. downstream converters • Drive towards more integration – System-basis devices (NCV885X) • EMC of high importance 4 Infotainment Power Requirements • Low current – Microcontrollers: 5.0 V, 3.3 V; 10’s to 100’s of milliamps of current – Sensors / transducers: tracking output; 10’s of milliamps of current • Low voltage, higher current – DSPs: 3.3 V, 1.8 V, 1.2 V; amps of current • Medium voltage, medium-higher current – DVD, CD, Tuner: 8.0 V; 100’s of milliamps to amps of current – Fans, blowers, motors: tracking output; amps of current • Pre-regulation boosting, high current – “Start/stop”: 18.0 V; many amps of current • High voltage – VFD: 64 V 5 Upstream vs. Downstream Converters 1. High power SMPS 1. Inexpensive SMPS 2. Low power stand-by LDOs 2. Higher current LDOs, too 3. Wide range, high input voltage 3. Narrow range, low input voltage – Battery – Load dump: Vin >= 45 V – Cold crank: Vin as low as 3-4 V 4. Expensive automotive-grade – NCV devices on PS5, I2T/I3T 5. Low-frequency SMPS – In design: NCV8901, 2 MHz 6 – Upstream converter – Typically: tight, regulated input 4. Inexpensive “consumer”-grade – NCP conversions 5. High-frequency SMPS available – 2+ MHz, multiple outputs Agenda • • • • • Infotainment Overview Regulation Options ON Semiconductor Solutions Example Applications System Power Architecture Design Examples 7 Regulation • Purpose: maintain constant output – Keep constant over input and load operating points (dc) – Minimize variation during transient perturbations (ac) • Most applications: voltage is regulated – Other applications: current is regulated, such as LED driving • Output is fixed or tracking – Fixed: output fed back, compared to internal, fixed reference – Tracking: output fed back, compared to external/variable reference • Remote output buffering, control via digital/analog converter (DAC) 8 Linear Regulation • Concept: Burn off excess voltage to regulate output voltage to value lower than input voltage • Resistive divider, dropping VIN – VOUT over RPASS • RPASS must be adjusted for changes in VIN and load (RL) • Regulation: Automatically adjust RPASS based on feedback 9 LDO Realization (Voltage-mode) • Output voltage is fed back, compared to reference – Internally fixed or externally adjustable output – Tracking regulator: reference voltage is also adjustable • Error amplifier adjusts pass transistor control signal – Pass transistor operates in linear/triode region • Power dissipation: (VIN-VOUT)*IOUT 10 What’s the Problem with LDOs? • Efficiency is very low with high conversion ratios VOUT, VIN = 13.2 V, vs. Efficiency • As current increases, power dissipation becomes very large 14 12 • • Large heat sinking is required for many applications From 13.2 V to 5 V, even just 500 mA is 4.1 W! If you’re going to be dissipating over 2 watts, consider using a switcher! 11 10 Output Voltage (V) • 8 6 4 2 0 100% 80% 60% 40% Efficiency (%) 20% 0% Switching: Who Needs It? • High current demands • Hot environments • High voltage conversion ratio • Voltage step-up or negative voltage generation • Isolation • Pre-regulation for down-stream LDOs (and other SMPS) • NCV8851 can go from 40 V to 5 V at 4 A with just 2.2 W of dissipation, spread out amongst the power stage and IC! 12 Switcher “Hand-waving” Explanation • Concept: Conservation of power from input to output to regulate output voltage (or current) to value lower, higher or equal to input voltage • Switches some source fully-on/fully-off • Source applies voltage to current storage element • Current storage element supplies current into voltage storage element Control • Voltage storage element provides output voltage • Regulation: Feedback from output voltage controls switch(es) 13 Switcher Topologies Primer • Buck • – Steps voltage down – High-side gate driver – NCV8842/43, NCV8851, NCV8901 – Steps voltage up – Low-side gate driver – NCV8871/72 VO =D VIN • Buck-Boost – Steps voltage up or down – Inverts sign (negative output) – Low-side gate driver VO D =− VIN 1− D 14 Boost VO 1 = VIN 1 − D • Buck-Boost Derived Topologies – Non-inverting, isolation – Flyback (turns ratio), SEPIC – Low-side gate driver VO nD = VIN 1 − D Synchronous vs. Non-synchronous • Primary, active, switch, QSW1: – Typically: MOSFETs • Low-side: NMOS • High-side: PMOS, NMOS – NMOS requires charge pump – BJTs also popular – IGBTs, SCRs, relays, tubes • Fundamentally same • Difference is in driving • “Rectifier”, QSW2: – Non-synchronous: • Passive rectification – Schottky diode • Lower efficiency at high load • Subject to DCM • Less complicated, single driver – Synchronous: • Active rectification – As primary switch • Higher efficiency at higher loads • No DCM • More complicated, dual, drivers – Avoid cross-conduction with non-overlap time 15 Switchers vs. LDOs for Automotive 1. Typically, poor efficiency at very light loads, otherwise very high efficiency 2. Minimal heat in package, less heat in pass devices 3. 10’s of amps is fine 4. Regulate at double battery, load dump, without much dissipation 5. Have to be careful with layout, components, compensators 6. Expensive magnetics, components 7. EMI a significant problem 8. Theory of operation is much more complicated, customers may not be use to switchers yet 16 1. Low efficiency over most conditions, but better than switchers at very light loads 2. Lots of heat, potentially watts in pass device 3. ½ of an amp is pushing it 4. Even running off typical battery causes lots of dissipation 5. Drop-in product, typically “just works”, regardless of layout, most components 6. Cheap! 7. EMI comparatively a non-issue 8. Theory of operation comparatively straight-forward, customers very acclimated to LDOs Controllers vs. Regulators 1. External pass element(s) (FET, BJT) 2. Less compact, more expensive 3. Power dissipation limited by pass element package 4. More heatsinking options 1. Internal pass element(s) (FET, BJT) 2. More compact, less expensive 3. Power dissipation limited by regulator package 5. Higher, flexible current capability 4. Less heatsinking options 6. Wide-range of external pass elements 5. Lower, fixed current capability • • 17 Not necessarily optimal Application selection / tuning process 6. Optimized for internal pass element Comparison of Power Devices SMPS Multi-Phase Controllers η > 95% Current Capability Io > 10 A Io > 4 A V η = IN VO ⎛ IQ ⎜⎜1 + ⎝ IO ⎞ ⎟⎟ ⎠ SMPS Non-Synchronous Controllers Io > 2 A η > 70% SMPS Non-Synchronous Regulators LDO Controllers SMPS Synchronous Regulators Io > 1 A Io > 500 mA VO I O η= VO I O + Pcond + Psw Io > 5 mA Efficiency 18 η > 80% Io > 3 A η > 20% LDO Regulators SMPS Synchronous Controllers Agenda • • • • • Infotainment Overview Regulation Options ON Semiconductor Solutions Example Applications System Power Architecture Design Examples 19 LDO Device Solutions 20 System Power Solutions • NCV885X – – – – – – • SMPS Buck Controller 2 A SMPS Buck Converter 2 LDO Controllers 2 A High-Side Switch 170 kHz, 340 kHz options Options with ROSC or SYNC – 3 LDO Outputs • Various voltage / current options • NCV8612 – Automatic Switch-Over (ASO) • Decrease power dissipation – Ultra Low Iq < 50 µA – DFN20 6x5 • Up to 600 kHz – QFN32 6x6 NCV861X • NCV8881 – 1.5 A SMPS Buck Converter – 8.5 V / 40 mA, 5.0 V / 100 mA LDOs – ROSC and SYNC • Up to 600 kHz – Watchdog – SOIC-16EP 21 Agenda • • • • • Infotainment Overview Regulation Options ON Semiconductor Solutions Example Applications System Power Architecture Design Examples 22 Many-Output NCV885X Application 23 NCV885X / NCV861X Application 24 NCV8855 5-Output NCV8851/NCV8855 25 4-Output NCV8851/NCV8610 BATT INPUT FILTER N1 OUTPUT FILTER N2 26 Agenda • • • • • Infotainment Overview Regulation Options ON Semiconductor Solutions Example Applications System Power Architecture Design Examples 27 System Power Architecture Considerations 1. Customer voltage / current requirements – Standby / Quiescent current 2. Cost! 3. Efficiency / power dissipation 4. Integration / size 5. EMC requirements 28 Example: System Power Requirements • Protected connection to battery 5.0 V / 1 A USB 5.0 V / 500 mA Tuner 5.0 V / 100 mA CAN SB • Standby HS-CAN IVN (CAN SB) • • 3.3 V / 1.3 A DSP 3.3 V / 70 mA µC SB • Standby microcontroller (µC SB) • 1.8 V / 600 mA HD • 50 µA max quiescent current (Iq) • Vbatt / 1.7 A Antenna • 8.0 V / 1.2 A CD • • • 29 Example: System Power Architecture #1 30 Example: System Power Architecture #1 31 Example: System Power Architecture #1 32 Example: System Power Architecture #2 33 Example: System Power Architecture #2 34 Example: System Power Architecture #2 Batt 13.2 V 34 µA Iq 1.419 W N 7.274 W η = 92% 863 mW 631 mA NCP3122 SMPS1 735 mA 180 mA 170 mA 1.979 W SMPS2 NCP1529 8.0 V / 1.2 A CD 922 mW N ASO VIN_S3 1.018 A 312 mW η = 85% 445 mW D 551 mW η = 85% 331 mW D 360 mW η = 75% NCV8612 170 mA 450 mA 35 2.218 A NCV8851 ηsys = 85.9% 34 µA Iq 954 mW P Batt / 1.7 A ANTENNA 1.700 A 3.918 A LDO1 LDO2 LDO3 329 mW 300 mW 1.350 W 3.3 V / 1.3 A DSP 5.0 V / 1.0 A USB 1.8 V / 600 mA HD 3.3 V / 70 mA uC SB 5.0 V / 100 mA CAN SB 5.0 V / 450 mA TUNER For More Information • View the extensive portfolio of power management products from ON Semiconductor at www.onsemi.com • View reference designs, design notes, and other material supporting automotive applications at www.onsemi.com/automotive 36