wpc low-power wireless charging solution - NXP Community

PUBLIC USE

EMMANUEL T. NANA

PRODUCT APPLICATIONS ENGINEER

SESSION #: FTF-MHW-N1923

THURSDAY, MAY 19, 2016 (11:00 AM)

WPC LOW-POWER WIRELESS CHARGING

SOLUTION

ULTRA-SMALL ONE-CHIP

LOW-POWER Qi TRANSMITTER

PUBLIC USE1 FTF-MHW-N1923 PUBLIC USE1 FTF-MHW-N1923

ABSTRACTCharging smartphones without the need to plug in a charging wire

increases convenience and enables on-the-move charging in public

spaces. First generation wireless chargers consist of over 100

components and are too expensive for mass market adoption. The

NXQ1TXH5 is a one-chip Qi low power wireless charging transmitter

integrating all the digital, analog and power functions for a Qi

wireless charger. The high integration enables a very low

component count and an easy to design wireless charger. This also

reduces the cost of a wireless charger by as much as a factor 3. The

NXQ1TXH5 is a real digital plug & play platform without the need for

external analog design effort. A 2-layer PCB with signal & power

routing at the top layer and a full copper bottom layer for thermal

performance is all you need. Connect power supply and decoupling

at the input and an LC circuit at the output to transmit the power to

the receiver, and your wireless charger is ready to go!

PUBLIC USE2 FTF-MHW-N1923 PUBLIC USE2 FTF-MHW-N1923

AGENGA

• Introduction to Wireless Charging

• Qi Wireless Charging Technology

• NXQ1TXH5 Low-Power Qi Transmitter

• System Application Information

• Summary

PUBLIC USE3 FTF-MHW-N1923

INTRODUCTION TO

WIRELESS

CHARGING


Why Wireless Charging

• Waterproofing and scalable designs

• Enables new designs and form factors

• Charging convenience


Wireless Power – Technology Overview

Inductive Coupling Magnetic Resonant Coupling

Coreless Transformer Resonant Coupling

mm z-distance

100..205 kHz

RF PowerLF Power

ASK Modulation

on Power Carrier

Bluetooth 4.0

Low-Energy

(2.4Ghz)

informationinformation

d<D

D

cm z-distance

6.78 MHz ± 15kHz

ASK Modulation

on Power Carrier

information

mm z-distance

201.. 304 kHz


Wireless Power System – Overview & Comparison

(Qi) System

PowerCircuit

Power Amp /Driver / MOSFETs

Tx

coilRx

coil

AC/DCWall

Adapter

TX RX

Control & ProtectionBLE

TX RX

PowerCircuit

Power Amp Driver

MOSFETs

Tx

coil

Rx

coilAC/DCWall

Adapter

Rectifier DC/DCDC/DC

(A4WP) System

A4WP – Rezence WPC – Qi

Communication/Control Bluetooth In-band ASK

User Experience Freedom of placement Coil alignment needed

Coil Sizes Customizable Specified

TX: RX connections Up to 8 1:1

Technology Emerging Mature

Control & Protection

Control&

Protection

Rectifier DC/DC

BLE

Control&

Protection MCUMCU


NXP Wireless Charging Solution Overview

BrightnessContrast

• NXP has a solid competitive position, supporting both Qi and A4WP standards

• NXP can offer interesting differentiators (like NFC)

• NXP makes wireless charging CHEAPER, BETTER, SMARTER

Wireless Charging Solutions from NXP

• Receivers

– Rezence (aka A4WP)

– Qi

– PMA

• Transmitters

– Qi

– PMA

RX TX

http://www.televisions.com/tvs/philips-televisions/philips-lcd-tvs/Philips-52-PFL-9704.php

http://www.televisions.com/tvs/philips-televisions/philips-lcd-tvs/Philips-52-PFL-9704.php


Qi-Enabled Phones Available Already

• Low power Qi is mature, simple, and low cost

• Medium power specification supports up to 15W

• Shared mode (more phones on charger) draft specification available


Wireless Chargers in Automotive


Qi WIRELESS

CHARGING

TECHNOLOGY


Qi System – Power and Control Loop

direction of

power transfer

feedback using backscatter

modulation of power carrier

pwr control loop

Tx Rx

AC

mains

Full/Half

bridge

inverter

Monitoring

&

(de)modulation

Supply

AC-DC

Converter Rsynchronous

rectifier

Rx

controller

PWR

RX device

Control(PWM/DAC/GPIO)

TX

pad

TX

Controller


Qi Transmitter Designs


Transmitter Ping Mode & Charge Mode

• Ping Mode:

− In this mode, the transmitter attempts to communicate

with the receiver

− Every 400ms, there is an analog ping at 175kHz (50%

duty cycle)

− Every 4s, there is an extra digital ping

• Charge Mode:

− In this mode, the transmitter transfers power to the

receiver

− Region of Operation: 110kHz – 205kHz (50% duty cycle)

− Above 205kHz, there is duty cycle control

ff0

P

Usable control region


Communication & Power Transfer

Power

Communication

Pad Device

Power Transmitter Power Receiver

ASK (load) modulation

communication channel


Qi Control Loop

• Receiver modulates load by

− Switching modulation resistor (Rm), or

− Switching modulation capacitor (Cm)

Transmitter

Cp

Lp

+

-

Receiver

Cd

Ls

Cs

C Rm

ModulationModulation

Cm

IpVp

Load

Power Modulation

Depth

pwr control loop

direction of

power transfer

feedback using backscatter

modulation of power carrier

Tx Rx


NXQ1TXH5

LOW-POWER Qi

TRANSMITTER


NXQ1TXH5: 5V Low-Power Qi Transmitter

• Features:

− Integrates A5, A11, A12, & A16 WPC Qi V1.2

analog and digital functions for 5W System

Specification

− Average output power up to 8W

− Easy FOD Control for coil and caps

− Internal voltage and current measurement circuits

− On-chip analog and digital filters for robust ASK detection

− No external OpAmp, filter, or biasing circuit needed

− Less than 10 external passive components required

− Low cost 32.768kHz external crystal for low power

oscillator to achieve standby current of <30µA; System

Standby Power of 10mW (typ)

− DSP wakeup by special device detect function

− Supports NFC tag applications with delayed startup

− Operates supply from 3.5V to 5.25V

− Small 5mm x 5mm HVQFN32 package

− Qi Certified

• Applications:

− Wearable Charger

− Mobile Charger

− Applications requiring

USB power, low cost

and low standby power

NXQ1TXH5/101


NXQ1TXH5: Dual ASK Channels for Safe Communication

Also possible to

measure RMS

coil current for

better FOD with

misalignment

101

Dual ASKCustomer

LED & FOD

Configuration


NXQ1TXH5: Static Power Reduction Configuration

• CNF1 (Pin 32) Setting via R7:VSPR < 0.04V: No SPR, No SPL

0.085V < VSPR < 1.29V: SPRLEVEL (mA) = 1000 x (VSPR / 1.2 + 0.43 ), adjustable from 500 to 1500 mA

1.335 < VSPR < VDDP: No SPR, SPL on

• With R11=390 kΩ, corresponding values of R7 are:R7 < 3 kΩ (0 Ω): No SPR, No SPL

7 kΩ < R7 < 136 kΩ: SPRLEVEL (mA) = 1000 x (VSPR / 1.2 + 0.43 )

R7 > 142 kΩ: No SPR, SPL on

• Determine value of R7 (SPR between 500 mA &1,500 mA):500 mA: R7 = 7 kΩ

1000 mA: R7 = 62 kΩ

1500 mA: R7 = 135 kΩ


NXQ1TXH5: FOD Threshold Configuration

• CNF3 (Pin 2) Setting via R9:VFOD_TH < 0.04V: FOD disable (R9 = 0 Ω, save resistor)

0.25 V < VFOD_TH < 1.29 V: FODTH (mW) = 1000 x (VFOD_TH / 1.5), adjustable from 166 to 860 mW

1.335 < VFOD_TH < VDDP: Default (350 mW), same as VFOD_TH = 525 mV (R9 ~47kΩ), but saving R9 (no mount)

• With R11=390kΩ, corresponding values of R9 are:R9 < 3 kΩ (0 Ω): FOD disable

21 kΩ < R9 < 136 kΩ: FODTH (mW) = 1000 x (VFOD_TH / 1.5)

R9 > 142 kΩ Reserved

• Determine value of R9:FODTH = 200 mW: R9 = 25 kΩ

FODTH = 400 mW: R9 = 53 kΩ

FODTH = 600 mW: R9 = 86 kΩ

FODTH = 800 mW: R9 = 123 kΩ


NXQ1TXH5: FOD Error Configuration

• CNF2 (Pin 1) Setting via R8:VFOD_E < 0.04V: FODE = 278 mΩ (same as for VFOD_E = 0.54V or R8 = 47 kΩ)

0.25V < VFOD_TH < 1.29V: FODE = 200 mΩ to 480 mΩ

1.335 < VFOD_TH < VDDP: Reserved

• With R11=390kΩ, corresponding values of R8 are:R8 < 3 kΩ (0 ohm)

21 kΩ < R8 < 136 kΩ

R8 > 142 kΩ

• Determine value of R8:FODE = 200 mΩ: R8 = 21 kΩ

FODE = 250 mΩ: R8 = 37 kΩ

FODE = 300 mΩ: R8 = 55 kΩ

FODE = 350 mΩ: R8 = 75 kΩ


NXQ1TXH5: LED Mode Configuration

• CNF4 (Pin 6) Setting via R10:

• 11 Modes (Mode 12 is reserved)

• Default mode (mode 11) needs LED_R connected inverted


NXQ1TXH5: LED Modes


Designing with NXQ1TXH5 (Schematic)

Dual ASK


Designing with NXQ1TXH5 (Layout)

• PCB bottom side completely copper

− No signal trace, especially near the NXQ1TXH5

• Thermal metalized vias under the exposed die

pad

− Minimum of 16 vias around the edge

− If filled vias are used, add 9 additional

vias in the middle

• Top layer power traces as wide as possible

− Output to coil connections (OUT1 & OUT2)

− VDDP connections (VDDP1 & VDDP2)

− GNDP connections

• Supply caps close to NXQ1TXH5 VDDP inputs

• Snubbers close to NXQ1TXH5 power outputs

NXQ1TXH5/101

45 x 45 mm PCB design(only 2-layer)

BOTTOM

No components,

almost no traces

TOP

few components

very simple layout


NXQ1TXH5: Measured System Efficiency

RX Output Power (mW)


NXQ1TXH5: Qi Certification Document

Low EMI without chock or shielding


SYSTEM

APPLICATION

INFORMATION


NXQ1TXH5DB1401: Demonstration Board Support


NXQ1TXH5: Scalable PCB Size (for Wearable Applications)

8.5W Transmitter(50mm for 5W RX out)

5W Transmitter(30mm)

3W Transmitter(20mm)

• 2-layer PCB

• Very low component count.

• Components on top-side only

• Easy for PCB design & manufacturing

• High efficiency (>70%)

• PCB Area scalable with power. PCB area only serves as heatsink:

– 30 mm diameter for TX design to deliver 3W at RX output (5W transmitter power)

– 20mm diameter for 2W design to deliver 2W at RX output (3W transmitter power)


NXQ1TXH5: In Samsung Gear S2 Wireless Charger (Wearable)

• NXQ1TXH5 with patched ROM to charge Gear S2− NXQ1TXH5 + LPC812 (for update with differences to Qi standard)

− Gear S2 transmitter coil connected to NXQ1TXH5DB1401

− Updated NXQ1TXH5 does not need LPC812 for same function

• Demo board NXQ1TXH5DB1402 configured as:− Red LED indicates charging

− Green LED indicates charged

− Foreign object detection switched off

• PCB area for Gear S2 design can be less than 50% of

5W PCB area with NXQ1TXH5

1.5W Solution

NXP Board Gear S2 Board

Gear S2 Design Analysis


Portable Qi Charger – Based on NXQ1TXH5


Qi Chargers – Based on NXQ1TXH5


SUMMARY


Summary

• NXQ1TXH5 Value Proposition

– Fully integrated, low-power Qi Wireless Transmitter

– 50% lower cost in the application than any other solution

– Compliant to WPC Qi V1.2, with easy FOD tuning

– Extremely low component counts for based Wireless Charger

– Peak system efficiency of 75%

– Extremely low standby power of ~10mW

– Low EMI by use of Class D audio expertise of NXP

– High efficiency and cool running by NXP C14P technology with low RDS(on)

• NXQ1TXA5 Suitability in Wearable Applications

– Very Low internal power consumption

– High system efficiency (>70%) at low power (1.5W); peak efficiency of 74%

– Integrated power stages with low switching loss

– Excellent fit for Wearable Qi Chargers


ATTRIBUTION STATEMENT

NXP, the NXP logo, NXP SECURE CONNECTIONS FOR A SMARTER WORLD, CoolFlux, EMBRACE, GREENCHIP, HITAG, I2C BUS, ICODE, JCOP, LIFE VIBES, MIFARE, MIFARE Classic, MIFARE

DESFire, MIFARE Plus, MIFARE FleX, MANTIS, MIFARE ULTRALIGHT, MIFARE4MOBILE, MIGLO, NTAG, ROADLINK, SMARTLX, SMARTMX, STARPLUG, TOPFET, TrenchMOS, UCODE, Freescale,

the Freescale logo, AltiVec, C 5, CodeTEST, CodeWarrior, ColdFire, ColdFire+, C Ware, the Energy Efficient Solutions logo, Kinetis, Layerscape, MagniV, mobileGT, PEG, PowerQUICC, Processor Expert,

QorIQ, QorIQ Qonverge, Ready Play, SafeAssure, the SafeAssure logo, StarCore, Symphony, VortiQa, Vybrid, Airfast, BeeKit, BeeStack, CoreNet, Flexis, MXC, Platform in a Package, QUICC Engine,

SMARTMOS, Tower, TurboLink, and UMEMS are trademarks of NXP B.V. All other product or service names are the property of their respective owners. ARM, AMBA, ARM Powered, Artisan, Cortex,

Jazelle, Keil, SecurCore, Thumb, TrustZone, and μVision are registered trademarks of ARM Limited (or its subsidiaries) in the EU and/or elsewhere. ARM7, ARM9, ARM11, big.LITTLE, CoreLink,

CoreSight, DesignStart, Mali, mbed, NEON, POP, Sensinode, Socrates, ULINK and Versatile are trademarks of ARM Limited (or its subsidiaries) in the EU and/or elsewhere. All rights reserved. Oracle and

Java are registered trademarks of Oracle and/or its affiliates. The Power Architecture and Power.org word marks and the Power and Power.org logos and related marks are trademarks and service marks

licensed by Power.org. © 2015–2016 NXP B.V.

wpc low-power wireless charging solution - NXP Community

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